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WO1998010115A1 - Revetements de carbone de type diamant dope au silicium pour transducteurs magnetiques et supports d'enregistrement magnetique - Google Patents

Revetements de carbone de type diamant dope au silicium pour transducteurs magnetiques et supports d'enregistrement magnetique Download PDF

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Publication number
WO1998010115A1
WO1998010115A1 PCT/US1997/007222 US9707222W WO9810115A1 WO 1998010115 A1 WO1998010115 A1 WO 1998010115A1 US 9707222 W US9707222 W US 9707222W WO 9810115 A1 WO9810115 A1 WO 9810115A1
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WO
WIPO (PCT)
Prior art keywords
silicon
dlc
gpa
ion beam
coating
Prior art date
Application number
PCT/US1997/007222
Other languages
English (en)
Inventor
David W. Brown
Bradley J. Knapp
Fred M. Kimock
Original Assignee
Monsanto Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Monsanto Company filed Critical Monsanto Company
Publication of WO1998010115A1 publication Critical patent/WO1998010115A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/26—Deposition of carbon only
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering
    • C23C14/46—Sputtering by ion beam produced by an external ion source
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/50—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges
    • C23C16/513—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges using plasma jets
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/187—Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features
    • G11B5/255—Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features comprising means for protection against wear
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
    • G11B5/8408—Processes or apparatus specially adapted for manufacturing record carriers protecting the magnetic layer

Definitions

  • This invention relates to transducer assemblies and media utilized in magnetic recording systems. More particularly, the invention relates to magnetic recording media and transducers for use with magnetic recording media, e.g. thin film magnetic heads, magnetoresistive (MR) read heads, inductive heads, sliders, and tape heads which are coated with a thin, protective layer of silicon-doped diamond-like carbon (Si-DLC), and a process for deposition of the Si-DLC layer.
  • MR magnetoresistive
  • Si-DLC silicon-doped diamond-like carbon
  • Magnetic transducers which include thin film magnetic heads, magnetoresistive read heads, inductive heads, sliders and tape heads utilized in magnetic recording systems have been known in the art for many years. The susceptibility of all magnetic heads (especially sliders) to damage during operation is well known.
  • the slider supports a thin film magnetic read/write head, which is formed by depositing layers of magnetic material, electrically conductive material, and electrically insulating material to form the magnetic poles, magnetic shields and magnetoresistive stripes which are the magnetic elements necessary for the transducing functions (reading and writing) with the magnetic coating on a magnetic recording medium.
  • a pattern of rails is produced on the lapped surface to form an air bearing surface which is used to "fly" the magnetic head over the magnetic recording medium.
  • the air bearing surface of the slider contacts the magnetic disk during start-up and shutdown of the disk rotation, and sometimes during operation. In conventional sliders and recording media, this contact results in transfer of disk material (wear debris) to the slider, which degrades the aerodynamics of the slider and increases friction. The presence of the wear debris and the increased friction can result in catastrophic failure and loss of stored information.
  • magnetic transducers such as thin film magnetic heads and magnetoresistive heads are fabricated from materials that are attacked by atmospheric constituents, such as moisture. Prolonged exposure of the transducer materials to atmosphere often results in degradation of performance due to oxidation and corrosion of the head materials.
  • Tape heads used with magnetic recording tape also suffer failure due to wear and corrosion.
  • the magnetic elements are worn away by abrasive materials in magnetic tape.
  • the magnetic materials on the tape head transducer are also degraded by environmental corrosion.
  • the protective coating For many designs of magnetic transducers, it is critical for the protective coating to be electrically nonconducting. This is especially true for magnetoresistive designs of tape heads or sliders. In these magnetoresistive designs, there are magnetic shields in the heads which shield the magnetoresistive sensor from the other elements of the head. Those shields can be either grounded or at potential, but always at a different potential than the sensor. It is not allowable to provide a path for electrical conduction between the shields to the sensor. Additionally, it is not allowable to provide an electrically conductive path between the sensor to any other element in head which is maintained at a different electrical potential. Finally, there are situations in which it is deleterious to allow electrical charge to pass directly between the transducer and the recording medium when the transducer and recording medium come into direct contact. An electrically nonconducting protective coating layer can protect against this problem.
  • amorphous diamond-like carbon (DLC) coatings are used as protective coatings on magnetic data storage recording media (i.e. hard disks) and magnetic transducers (including sliders) to increase the wear resistance and durability of the head-disk interface.
  • DLC coatings is due to their excellent mechanical properties such as high hardness and low coefficient of friction, and excellent resistance to abrasion, and resistance to corrosion by water, acids, bases, and solvents.
  • DLC films are so-named because their properties resemble, but do not duplicate, those of diamond. Some of these properties are high hardness of about 1,000 kg/mm 2 (10 GPa) to about 5,000 kg/mm 2 (50 GPa), low -friction coefficient (approximately 0.1), and transparency across the majority of the electromagnetic spectrum. At least some of the carbon atoms in DLC are bonded in chemical structures similar to that of diamond, but without long range crystal order. Although the term DLC was initially intended to define a pure carbon material, the term DLC is now used to include amorphous, hard carbon materials containing up to 50 atomic percent of hydrogen. Other names for these hydrogen-containing DLC materials are "amorphous hydrogenated carbon", hydrogenated diamond-like carbon, or diamond-like hydrocarbon.
  • DLC hydrogen-containing DLC materials
  • the structure of these hydrogen-containing DLC materials may be best described as a random covalent network of graphitic-type structures interconnected by sp 3 linkages, although the definitive structure of the films has yet to be universally accepted.
  • DLC is used herein to refer to both the amorphous non-hydrogenated hard carbon materials, and the amorphous hydrogenated hard carbon materials.
  • the DLC coatings may also contain nitrogen and are thus termed "nitrogenated DLC".
  • DLC films Many methods for preparation of DLC films are known in the prior art, including (i) direct ion beam deposition, dual ion beam deposition, glow discharge, radio frequency (RF) plasma, direct current (DC) plasma or microwave plasma deposition from a carbon-containing gas or vapor which can also be mixed with hydrogen and/or inert gas, (ii) electron beam evaporation, ion-assisted evaporation, magnetron sputtering, ion beam sputtering, or ion-assisted sputter deposition from a solid carbon target material, or (iii) combinations of (i) and (ii).
  • RF radio frequency
  • DC direct current
  • microwave plasma deposition from a carbon-containing gas or vapor which can also be mixed with hydrogen and/or inert gas
  • Magnetic transducer assemblies are made up of a variety of materials, including the alumina-titanium carbide (Al 2 O 3 -TiC), alumina (Al 2 O 3 ), nickel-iron (NiFe) alloys, and iron-silicon-aluminum (FeSiAl) alloys.
  • any protective coating should have sufficient adhesion to all of these materials.
  • DLC coatings are typically under significant compressive stress, on the order of 5 x 10 9 dynes/cm 2 (0.5 GPa) to about 5 x 10'° dynes/cm 2 (5 GPa). This stress greatly affects the ability of the coating to remain adherent to the substrate. Additionally, the surface of the substrate to be coated often contains alkali metals, oxides, and other contaminants which can inhibit bonding of the DLC coating. Even with an atomically clean surface the adhesion may be insufficient between DLC and particular substrate materials. Therefore, less obvious methods are required to produce a substrate with a highly adherent DLC coating which provides excellent abrasion resistance.
  • U.S. Pat. No. Re 32,464 teaches a magnetic recording medium coated with a sputter-deposited graphitic carbon protective layer having thickness between 1-5 microinches. Use of an adhesion-promoting carbide-forming layer between the disk and the carbon film is disclosed and claimed. Additionally, "the magnetic transducer head portion which occasionally sinks into contact with the recording medium is preferably formed of or coated with carbon, preferably in the form of graphite, to provide a low friction wear resistant contacting surface with the recording medium". The carbon layer may also be deposited by ion plating.
  • Japanese Laid Open Pat. Application (Kokai) No. 1-287819, Shinora claims a magnetic recording medium (magnetic disk or magnetic tape) in which a diamond-form hard carbon thin film is located on a strongly magnetic metal thin film with a silicon or germanium layer, having thickness of 20 A to 50 A interposed between the two.
  • the diamond-like carbon film has a thickness between 50 A and 100 A and can be formed by high frequency sputtering, ion beam deposition, or plasma acceleration.
  • the DLC layer is then overcoated with a lubricant to form the final product.
  • a magnetic recording medium composed of a magnetic film formed on the surface of a disk-shaped substrate and a protective film further formed on the surface of the magnetic film.
  • the protective film is composed of a first layer containing silicon, germanium, or chromium oxide, and a second (top) layer of amorphous carbon or graphite-containing amorphous carbon.
  • the first and second layers can be formed by a variety of sputtering techniques including magnetron sputtering, diode sputtering, and ion beam sputtering.
  • the thickness of a first layer of elemental silicon is in the range of 100 A to 300 A
  • the second carbon layer has a thickness in the range of 200 A to 700 A.
  • Kurokawa et al. U.S. Pat. No. 4,717,622, discloses a magnetic recording medium with a protective layer of high hardness carbon synthesized under a low temperature and low pressure gas plasma.
  • the magnetic recording medium is useful in a system where the magnetic head contacts the magnetic recording medium.
  • the diamond-like carbon film has a Vicker's hardness of more than 2,000 kg/mm 2 (20GPa), and a specific resistance of 10 7 ohm-cm to 10 13 ohm-cm.
  • an abrasion resistant magnetic recording member comprising a carbonaceous surface protective film on a surface of a magnetic film on the surface of a nonmagnetic substrate.
  • the protective film has a lower layer of comparatively hard carbonaceous film and an upper layer of comparatively soft carbonaceous film.
  • An intermediate layer of chromium, titanium, etc. may by used to improve the adhesion of the carbonaceous film to the magnetic film.
  • the lower carbonaceous layer contains 5 atomic percent or less of hydrogen, fluorine, or a combination of hydrogen and fluorine
  • the upper carbonaceous layer contains 6 atomic percent or more or hydrogen, fluorine, or a combination of hydrogen and fluorine.
  • the lower carbonaceous layer may be a sputtered carbonaceous film
  • the upper layer may be a plasma chemical vapor deposited (PCVD) carbonaceous film.
  • 5, 151 ,294 discloses a method for depositing a thin protective carbon film on the air bearing surface of a slider in a magnetic recording disk file by contacting the slider and a rotating magnetic disk for a time sufficient to cause transfer of the carbon from a carbon overcoated disk to the air bearing surface of the slider.
  • the patentees teach that the carbon film formed on the slider is an essentially amorphous hydrogenated carbon film approximately 50 A in thickness.
  • Japanese Laid Open Pat. Application (Kokai) No. 3-25716 discloses a magnetic head slider, characterized by the fact the head slider body is made of a soft ceramic material, such as ferrite, and a hard ceramic membrane such as carbon, silicon, zirconium dioxide, aluminum oxide, or the like, which is bonded and molded onto at least the pressure-receiving surface of the slider which faces the magnetic disk.
  • a hard ceramic membrane such as carbon, silicon, zirconium dioxide, aluminum oxide, or the like, which is bonded and molded onto at least the pressure-receiving surface of the slider which faces the magnetic disk.
  • the hard ceramic membrane has a thickness in range of several hundred Angstroms, and may be made by a plasma chemical vapor deposition (PCVD) method.
  • PCVD plasma chemical vapor deposition
  • Head et al. U.S. Pat. No. 4, 130,847, describes a magnetic head slider having a protective coating preferably chromium over at least the magnetic head.
  • the coating is produced in a recess within the slider body to a thickness as small as 10 microinches.
  • Grill et al., U.S. Pat. No. 5, 159,508, teaches a magnetic head slider coated with an adhesion layer and a protective DLC layer. The coating is fabricated onto the substrate after a lapping operation, but before patterning of the rails onto the slider, which protects the magnetic head during the fabrication process.
  • the slider has at least two rails on the air bearing surface, and the rails have a protective coating comprising an adhesion layer, typically about 10 A to 50 A in thickness, and a thin layer of amorphous hydrogenated carbon, less than about 250 A thick.
  • Grill et al. teach that the two layers of the protective coating can be deposited by any suitable technique, e.g. PACVD, ion beam or laser techniques. The preferred technique is by the use of a DC biased substrate in an RF plasma deposition apparatus.
  • German Pat. Application No. DE 3,714,787 describes a storage system in which the surface of a magnetic disk is coated with friction-reducing carbon and the rails of the magnetic head slider are coated with a friction reducing carbon.
  • the thickness of the carbon is 10 A to 1000 A.
  • Knapp et al. teach a direct ion beam process for deposition of DLC protective coatings on magnetic transducers such as sliders and tape heads, which provides remarkable performance compared to the prior art techniques discussed above.
  • a silicon-containing adhesion layer consisting of amorphous silicon, silicon carbide, silicon nitride, silicon oxide, silicon oxy-nitride is deposited onto the magnetic transducer substrate prior to ion beam deposition of the DLC top coating layer.
  • increased storage density can be achieved by a reduction in the distance (i.e. magnetic spacing) between the head and the magnetic layers on the recording disk.
  • One way to reduce the magnetic spacing between the head and the disk is to reduce the thickness of the protective coating on the disk and the transducer assembly containing the head.
  • the ion beam DLC deposition process of copending application Serial No. 08/607,657 has been used to deposit protective DLC coatings at total thicknesses (thickness of interlayer plus thickness of DLC layer) of less than 65 A.
  • the total thickness of the protective coating on heads must be reduced to less than 50 A, and possibly to as low as 20 A.
  • the disk upon complete wear removal of the DLC, the disk is exposed to direct contact with the adhesion layer material. Sliding contact of the disk with some typical adhesion layer materials, such as silicon, can lead to premature failure of the head-disk interface. This is to say that the exposed adhesion layer can generate more wear debris or have higher friction than even an uncoated slider. A new, low friction coating material that required no adhesion layer would solve this problem. Another reason to eliminate the adhesion layer is to reduce the number of manufacturing steps, thus reducing any yield loss and manufacturing complexity associated with deposition of the adhesion layer. A third reason involves quality control of the coated substrates. It is easier to analyze and assign cause to variation in a single layer coating process than in a two layer process, i.e.
  • the invention provides a process for depositing a protective coating onto magnetic media and magnetic transducers to impart superior wear resistance, and improved lifetime. More particularly, this invention provides an ion beam deposited Si-doped DLC (Si-DLC) coating to the surface of magnetic transducers and magnetic media which is highly adherent without use of an adhesion enhancing interlayer, and exhibits greatly improved wear resistance and environmental durability. This invention also provides a low cost and efficient process for mass-producing the coated magnetic transducers and magnetic recording media with improved wear resistance and superior lifetime.
  • Si-DLC Si-doped DLC
  • the wear surface of a magnetic recording media substrate or a magnetic transducer is provided with a single coating layer of Si-DLC that requires no adhesion-enhancing interlayer.
  • the invention further provides a method for fabricating the protective Si-DLC coating on the surface of magnetic transducers and magnetic recording media.
  • the surface of the magnetic transducer or recording media substrate is chemically cleaned to remove unwanted materials and other contaminants.
  • the substrate is inserted into a vacuum chamber, and the air in said chamber is evacuated.
  • the substrate surface is sputter-etched with energetic ions to assist in the removal of residual contaminants, i.e. hydrocarbons and surface oxides, and to activate the surface.
  • a Si-DLC layer is deposited by ion beam deposition.
  • the deposition process on the substrates is terminated, the vacuum chamber pressure is increased to atmospheric pressure, and the Si-DLC-coated substrates are removed from the vacuum chamber.
  • the Si-DLC layer may be ion beam deposited onto the wear surface of a magnetic recording media substrate immediately upon completion of deposition of the magnetic material layer in vacuum.
  • the Si-DLC coatings of the present invention are characterized by having the following features: a Nanoindentation hardness in the range of about 12 GPa to about 70 GPa, a compressive stress in the range of about 0.4 GPa to about 10 GPa, Raman spectral G-peak position in the range of about 1425 cm “ ' to about 1530 cm “1 , and a silicon concentration in the range of about 1 atomic % to about 45 atomic % .
  • Ion beam deposited Si-DLC materials of the present invention which contain hydrogen typically exhibit a hydrogen concentration in the range of about 25 atomic % to about 47 atomic %.
  • FIG. 1 is an illustration of the ion beam deposition apparatus used to manufacture Si-DLC coatings on magnetic transducers and magnetic recording media (e.g. hard disks) in accordance with the present invention
  • FIG. 2A is a graph of frictional force versus the number of test revolutions in a constant speed drag test for an uncoated Al 3 O 3 -TiC slider;
  • FIG. 2B is a graph of touch down velocity change versus the number of test revolutions in a constant speed drag test for an uncoated Al 2 O 3 -TiC slider;
  • FIG. 2C is a graph of frictional force versus the number of test revolutions in a contact-start-stop test for an uncoated Al 2 O 3 -TiC slider
  • FIG. 2D is a graph of touch down velocity change versus the number of test revolutions in a contact-start-stop test for an uncoated Al 2 O 3 -TiC slider
  • FIG. 3 A is a graph of frictional force versus the number of test revolutions in a constant speed drag test for a slider coated with a 25 A thick ion beam sputter-deposited Si adhesion layer, and a 100 A thick top layer of ion beam deposited DLC;
  • FIG. 3B is a graph of touch down velocity change versus the number of test revolutions in a constant speed drag test for a slider coated with a 25 A thick ion beam sputter-deposited Si adhesion layer, and a 100 A thick top layer of ion beam deposited DLC;
  • FIG. 4A is a graph of frictional force versus the number of test revolutions in a constant speed drag test for a slider coated with a 25 A thick ion beam sputter-deposited Si adhesion layer, and a 50 A thick top layer of ion beam deposited DLC;
  • FIG. 4B is a graph of touch down velocity change versus the number of test revolutions in a constant speed drag test for a slider coated with a 25 A thick ion beam sputter-deposited Si adhesion layer, and a 50 A thick top layer of ion beam deposited DLC;
  • FIG. 5A is a graph of frictional force versus the number of test revolutions in a contact-start-stop test for a slider coated with a 25 A thick ion beam sputter-deposited Si adhesion layer, and a 100 A thick top layer of ion beam deposited DLC
  • FIG. 5B is a graph of touch down velocity change versus the number of test revolutions in a contact-start-stop test for a slider coated with a 25 A thick ion beam sputter-deposited Si adhesion layer, and a 100 A thick top layer of ion beam deposited DLC;
  • FIG. 6 is a representative laser Raman spectrum and curve fit analysis of an ion beam deposited DLC coating deposited using a feed gas of 12 seem methane and an ion beam energy of 150 Volts;
  • FIG. 7 is a laser Raman spectrum and curve fit analysis of a Si-DLC coating of the present invention deposited using a gas feed mixture of 3.6 seem of tetramethylsilane and 5 seem of argon, at a beam voltage of 350 Volts;
  • FIG. 8 is a graph of hardness and compressive stress versus ion beam energy ("beam voltage") for representative Si-DLC coatings of the present invention deposited using a gas feed mixture of 3.6 seem of tetramethylsilane and 10 seem of argon;
  • FIG. 9 is a graph of laser Raman G-peak position versus ion beam voltage for Si-DLC coatings of the present invention deposited using a feed gas mixture of 20 seem of tetramethylsilane and 10 seem of argon;
  • FIG. 10 is a graph of hardness and compressive stress versus the flow rate of tetramethylsilane added to 12 seem of methane in the precursor feed gas mixture for representative Si-DLC coatings of the present invention deposited at an ion beam energy of 200 Volts;
  • FIG. 11 is a graph of the atomic concentration of carbon, silicon, hydrogen and argon in Si-DLC coatings of the present invention versus tetramethylsilane flow rate added to 12 seem of methane in the precursor gas feed, for coatings deposited at an ion beam energy of 200 Volts;
  • FIG. 12 is a graph of laser Raman G-peak position versus tetramethylsilane flow rate added to 12 seem of methane in the precursor gas feed, for Si-DLC coatings of the present invention deposited at an ion beam energy of 200 Volts;
  • FIG. 13 is a graph of hardness and compressive stress versus substrate angle for DLC coatings deposited at 150 Volts ion beam energy and a precursor gas flow rate of 12 seem methane;
  • FIG. 14 is a graph of hardness and compressive stress versus substrate angle for representative Si-DLC coatings of the present invention deposited at 350 Volts ion beam energy and a precursor gas mixture of 3.6 seem tetramethylsilane and 5 seem argon.
  • the method of the present invention substantially reduces or eliminates the disadvantages and shortcomings associated with the prior art transducer assemblies for magnetic recording media (e.g. sliders, inductive heads, magnetoresistive head, tape head, thin film head, and similar devices, etc.) by providing:
  • transducer assembly for use with magnetic recording media, in which the transducer has an improved protective coating
  • amorphous Si-DLC coating for the deposition of an amorphous Si-DLC coating onto the surface of a transducer assembly, which surface faces the magnetic recording media, in which the amorphous Si-DLC coating has the properties of impermeability to environmental elements such as water vapor and oxygen, high density, and extreme surface smoothness;
  • the method of the present invention substantially reduces or eliminates the disadvantages and shortcomings associated with the prior art magnetic data recording substrates (e.g. hard disks) by providing:
  • the ion beam deposited Si-DLC coating of the present invention protects the magnetic transducer assembly and magnetic recording media from wear and corrosion damage during normal operation and significantly extends the lifetime of the magnetic recording data storage system.
  • the ion beam deposited Si-DLC coating eliminates the requirement for an adhesion layer, allowing for a substantial reduction of the total coating thickness of the protective coating, and for simplified manufacture. Additionally, the method for manufacture of the ion beam deposited Si-DLC coating substantially reduces or eliminates the disadvantages and shortcomings of prior art DLC coating processes. It is not intended by the discussion of a particular transducer assembly or magnetic recording medium to limit the method of the present invention to any particular type of transducer, e.g. sliders, or tape heads, or magnetic recording medium, e.g. hard disks.
  • the ion beam deposited Si-DLC coatings unexpectedly have tribological properties that are comparable to, or superior to standard DLC coatings as measured in typical mechanical tests used to evaluate protective coatings on magnetic heads.
  • the ion beam deposited Si-DLC has unexpectedly good adhesion to the sliders without the need for an adhesion layer.
  • the Si-DLC, without an adhesion layer enables: reduced total thickness of the protective coating, elimination of the manufacturing process steps and quality control associated with adhesion layer deposition, and elimination of adhesion layer materials that can cause premature failure when exposed during use of the slider.
  • the ion beam process overcomes the difficulties in obtaining an atomically clean surface prior to deposition by sputter-etching the substrates using an ion beam of controlled shape, current, and energy.
  • the ion beam "shape" is controlled by focusing the beam with electrostatic or magnetic fields. In this way, the beam can be efficiently delivered to the substrates to be processed, with maximum utilization. Control of ion beam current and beam energy to within 1 % is routinely achieved which results in a highly repeatable and predictable rate of removal of surface residual hydrocarbons and other contaminant layers.
  • the ion beam sputter-etching process is conducted in high vacuum conditions, such that oxidation or contamination of the transducer surface with residual gases in the coating system is negligible.
  • the apparatus geometry can be easily configured such that the sputtered contaminants deposit on the vacuum chamber walls, and do not redeposit onto the surface of the part as it is being sputter-etched.
  • the ion beam deposition process produces a protective Si-DLC layer directly on the atomically clean ion etched substrate which adheres without use of an adhesion layer.
  • the Si-DLC layer is preferably deposited immediately upon completion of the ion beam sputter-etching step to achieve maximum density and adhesion to the substrate. Deposition of the Si-DLC layer immediately upon completion of the ion beam sputter-etching step minimizes the possibility for recontamination of the sputter-etched surface with vacuum chamber residual gases or other contaminants.
  • the ion beam deposition process produces highly dense Si-DLC coatings. This makes these Si-DLC coatings excellent barriers to water vapor and oxygen. The excellent barrier properties of the thin ion beam deposited Si-DLC coatings presumably result from the extremely high degree of ion bombardment during film growth. In addition, the Si-DLC coatings of the present invention are also exceedingly smooth, resulting in a surface with high resistance to wear. (6) Ion beam deposition produces coherent, dense ion beam Si-DLC coatings having thickness of 50 A or less and providing magnetic transducers and sliders with excellent wear protection.
  • the ion beam deposition process produces highly electrically nonconducting Si-DLC coating layers. Use of these electrically nonconducting Si-DLC layers provides improved performance of magnetoresistive sliders, magnetoresistive tape heads, and other transducers, compared to prior art methods.
  • the ion beam deposition process produces a coating with properties that do not change as a function of layer thickness, as is found in prior art RF plasma deposition processes. This attribute is achieved because the coating deposition step is preferably conducted with a charge neutralized ion beam.
  • the use of charge neutralized ion beam deposition process also allows for coating of parts with complex geometry without interference to the process. Parts of varying geometry can be coated within a single coating run with no adverse effect on the deposition conditions. Complete slider assemblies, tape heads, other transducer assemblies, and magnetic recording disks can be easily coated. In addition, on substrates which contain electrically conducting and electrically insulating materials, all portions can be coated with the same high quality Si-DLC coating.
  • Si-DLC coatings of different properties may be deposited on different locations of the same substrate, depending upon whether the area being coated is an electrical conductor or an electrical insulator, and the electrical connections between the substrates and the vacuum chamber.
  • the lack of substrate geometry constraints of the present invention is in sha ⁇ contrast to the plasma deposition methods of the prior art.
  • the ion beam process allows easy fixturing of magnetic transducer assemblies and magnetic recording disks. Because of the ease of fixturing transducer substrates of nearly any shape or configuration, the ion beam process of the present invention can be used to apply a Si-DLC coating to a transducer during any part of the magnetic transducer fabrication or assembly process.
  • the Si-DLC coating can be applied (i) during fabrication of the transducer element, (ii) after fabrication of the transducer element, but before completion of the final transducer assembly, or (iii) after completion of the final transducer assembly.
  • the ion beam process is capable of minimal batch-to-batch variation in the properties of the Si-DLC coatings. This is the case because process parameters such as ion energy, ion current density, gas flow rate, and deposition chamber pressure are largely decoupled in the ion beam deposition method of the present invention, and because each of these process parameters can be accurately controlled and reproduced to a high degree of certainty, often to within 1 % . In addition, the process endpoint for Si-DLC coating thickness is easily defined and reproduced.
  • the ion beam deposition process is capable of tight part-to-part thickness uniformity, e.g. a variation of less than 2% can be easily achieved. This is the case because of the compatibility of the method of the present invention with commercially available substrate holders inco ⁇ orating motion, i.e. rotation and/or planetary motion.
  • the ion beam process is readily scaled-up to accommodate mass production because large scale ion beam sources are commercially available. For example, commercially available 38 cm Kaufman-type gridded ion beam sources have been used to deposit DLC coatings simultaneously over four 18-inch diameter platens with a thickness variation across all parts of less than +/- 2% . Similar ion beam sources can be used to practice the Si-DLC process of the present invention. Plasma deposition systems for deposition of Si-DLC coatings on magnetic transducers and media are not presently commercially available on this scale. The inventors have discovered that the ion beam deposited Si-DLC coatings of the present invention provide magnetic transducers and recording media with an outstanding wear and corrosion resistant surface.
  • the DLC matrix is capable of encapsulating the silicon, provided that the ratio of silicon-to-carbon atoms in the coating is less than 1.0, and preferably less than about 0.9.
  • the coating material could have bonding characteristics of silicon carbide, or may begin to develop free, unbonded silicon, which would be detrimental to the head-disk interface.
  • the apparatus for carrying out the preferred embodiment form of the invention is illustrated schematically in FIG.1. The coating process is carried out inside a high vacuum chamber 1 which is fabricated according to techniques known in the art.
  • Vacuum chamber 1 is evacuated into the high vacuum region by first pumping with a rough vacuum pump (not shown) and then by a high vacuum pump 2.
  • Pump 2 can be a diffusion pump, turbomolecular pump, cryogenic pump (“cryopump”), or other high vacuum pumps known in the art.
  • cryopump cryogenic pump
  • the use of cryopumps with carbon adsorbents is somewhat less advantageous than other high vacuum pumps because those cryopumps have a low capacity for hydrogen which is generated by the ion beam sources used in the present invention for the deposition of Si-DLC. The low capacity for hydrogen results in the need to frequently regenerate the adsorbent in the cryopumps.
  • the process of the present invention can be carried out in a batch-type vacuum deposition system, in which the main vacuum chamber is evacuated and vented to atmosphere after processing each batch of parts; a load-locked deposition system, in which the main vacuum deposition chamber is maintained under vacuum at all times, but batches of parts to be coated are shuttled in and out of the deposition zone through vacuum-to-air load locks; or in-line processing vacuum deposition chambers in which parts are flowed constantly from atmosphere, through differential pumping zones, into the deposition chamber, back through differentia] pumping zones, and returned to atmospheric pressure.
  • Magnetic transducer substrates or magnetic recording media substrates to be coated are mounted on substrate holder 3, which may inco ⁇ orate tilt, simple rotation, planetary motion, or combinations thereof.
  • the substrate holder can be in the vertical or horizontal orientation, or at any angle in between. Vertical orientation is preferred to minimize paniculate contamination of the substrates, but if special precautions such as low turbulence vacuum pumping and careful chamber maintenance are practiced, the substrates can be mounted in the horizontal position and held in place by gravity. This horizontal mounting is advantageous from the point of view of easy fixturing of small substrates such as individual sliders. This horizontal geometry can be most easily visualized by rotating the illustration in FIG.1 by 90 degrees.
  • the transducer substrates Prior to deposition, are ion beam sputter-etched with an energetic ion beam generated in ion beam source 4.
  • Ion beam source 4 can be any ion source known in the prior art, including Kaufman-type direct current discharge ion sources, radio frequency or microwave frequency plasma discharge ion sources, each having one, two, or three grids, or gridless ion sources such as the End Hall ion source of U.S. Pat. No. 4,862,032.
  • the ion source beam is charge neutralized by introduction of electrons into the beam using a neutralizer (not shown), which may be a thermionic filament, plasma bridge, hollow cathode, or other types known in the prior art.
  • ion source 4 is provided with inlets for introduction of inert gases 5, such as argon, krypton, and xenon, for the sputter-etching, and for introduction of precursor gas mixtures 6, for deposition of Si-DLC layers.
  • inert gases 5 such as argon, krypton, and xenon
  • the precursor gas mixture is made up of silicon-containing compounds including, but not limited to silane compounds such as silane and disilane, and organosilane compounds such as methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane (TMS) and diethylsilane (DES) which may be mixed with hydrocarbon compounds including, but not limited to methane, ethane, acetylene, cyclohexane, and mixtures thereof and inert gases such as argon, krypton, xenon and mixtures thereof.
  • the precursor gas mixture may further contain nitrogen (N 2 ), or organosilane compounds or organic compounds which contain nitrogen.
  • a critical feature is that a silicon-containing precursor gas is introduced into the ion beam source to provide the silicon doping level in the Si-DLC coatings which is required to obtain excellent adhesion and tribological performance of the Si-DLC coatings of the present invention.
  • An additional ion source (not shown) can be used to co-bombard the substrates during Si-doped DLC deposition to alter the film properties.
  • An additional ion beam source 7, is also provided for ion beam sputter deposition of silicon and/or carbon atoms onto the substrate to alter the stoichiometry (silicon-to-carbon atomic concentration ratio) during deposition of the Si-DLC layer.
  • Ion beam source 7 is provided with inlets for operation on inert gases 8, such as argon, krypton, and xenon, or for reactive gases 9, such as methane or nitrogen.
  • the ion beam from source 7 is directed onto a sputtering target 10, which can be silicon, carbon, a mixture of silicon and carbon, or silicon carbide, depending on the desired stoichiometry of the Si-DLC layer, the operating conditions of ion source 4, and the precursor gases introduced in inlet 6.
  • the surface of the substrate is first chemically cleaned to remove contaminants.
  • Ultrasonic cleaning in solvents, or other detergents as known in the art is often effective; details of the cleaning depend upon the nature of the contamination and residue remaining on the part after the finishing operations. It has been found that it is critical for this step to be effective in removing surface contaminants and residues, or the resulting adhesion of the Si-DLC coating will be poor. This is because in many designs of magnetic transducers and recording media, only a very small amount, e.g. ⁇ 100 A, of surface material can be removed during the subsequent in-vacuum cleaning by ion beam sputter-etching step. For example, for the case of magnetic transducers, minimizing the sputter-etching step is critical in order to minimize pole-tip recession.
  • the substrate is inserted into a vacuum chamber, and the air in said chamber is evacuated.
  • the vacuum chamber is evacuated to a pressure of about 1 x 10 "5 Torr or less to ensure removal of water vapor and other contaminants from the vacuum system.
  • the required level of vacuum which must be attained prior to initiating the next step must be determined by experimentation. The exact level of vacuum is dependent upon the nature of the substrate material, the sputter-etching rate, and the constituents present in the vacuum chamber residual gas.
  • the substrate surface is bombarded with energetic gas ions to assist in the removal of residual contaminants, e.g. any residual hydrocarbons, surface oxides, material smeared metal from lapping, and other contaminants, and to activate the surface.
  • This sputter-etching of the magnetic transducer or magnetic recording media substrate surface is required to achieve high adhesion of the Si-DLC layer.
  • the sputter-etching is typically carried out with inert gases such as argon, krypton, and xenon, but other gases (e.g. nitrogen) can be used if they due not adversely affect adhesion. Additionally, hydrogen may be added to the ion beam during sputter-etching to assist in activation of the surface.
  • the ion beam energy is greater than 20 eV. Ion energies as high as 2000 eV can be used, but ion beam energies in the range of about 20 to about 500 eV result in the least amount of atomic scale damage to the magnetic transducer or magnetic recording media substrate.
  • the shape and surface mo ⁇ hology of the substrate should not be significantly affected by application of the protective coating. Due to the higher ion beam etch rates of magnetic materials compared to ceramics, a phenomenon known as "pole-tip recession" can occur in magnetic transducers if the ion beam sputter-etching process is operated at the incorrect condition, or for an extended period of time. Minimizing the sputter-etching time to remove ⁇ 100 A of material, operating with a beam of heavy inert gas (e.g. xenon) ions, and varying ion beam energy and angle can be used to minimize the effects of differential etching and pole recession.
  • a beam of heavy inert gas e.g. xenon
  • the Si-DLC layer is deposited by ion beam deposition. It is important to minimize the time between completion of the etch step and the start of the deposition of the Si-DLC layer. Deposition of the Si-DLC layer immediately after completion of the sputter-etching step minimizes the possibility for recontamination of the substrate surface with vacuum chamber residual gases or other contaminants.
  • the thickness of the protective ion beam deposited Si-DLC coating is constrained to small dimensions since the coating thickness adds directly to the magnetic spacing between the magnetic transducer and the magnetic recording medium. Depending on the design and operation of the transducer, the Si-DLC coating thickness is typically in the range of about 20 A to about 2,000 A.
  • Thicker Si-DLC layers are generally preferable in terms of providing increased protection against wear and corrosion, although outstanding wear and corrosion resistance is also obtained by ion beam deposited Si-DLC coatings at the low end of this thickness range.
  • the actual thickness of the ion beam deposited DLC layer is chosen in practice based on either (i) the maximum allowable increase in magnetic spacing, or (ii) the minimum thickness that will perform without failure for a required period of operation.
  • Several ion beam deposition methods may be used for the formation of the
  • Si-DLC coatings of the present invention including: (1) direct ion beam deposition from silicon-containing precursor gas mixtures described above, (2) direct ion beam deposition from silicon containing gas mixtures in combination with a second ion "assist" beam directed at the substrate, i.e. "direct dual ion beam deposition", (3) ion beam sputter deposition from a silicon-doped carbon sputtering target, (4) ion beam sputter deposition with ion assist, i.e.
  • the assist beam is typically composed of inert gas ions that are used to sputter unwanted material from the depositing film or to add energy to the surface region of the growing film to influence chemical bonding.
  • the ion beam sputter deposition methods offer excellent control, uniformity, and flexibility of substrate geometry, but the deposition rate is slower than that of the direct ion beam deposition process.
  • bombardment of the growing film by an additional ion beam is performed to maximize the film density and improve the electrical resistivity of the ion beam sputter-deposited Si-DLC coating.
  • Ion beam sputter deposition from a carbon or silicon target can also be used in combination with direct ion beam deposition to add carbon or silicon atoms, respectively, to the growing Si-DLC film.
  • the elemental composition of the direct ion beam deposited Si-DLC film may be modified during deposition to achieve the desired stoichiometry.
  • the gas mixture fed to direct deposition ion source may not necessarily include a silicon-containing precursor gas (i.e. may be hydrocarbon gas only) if sufficient silicon is deposited into the growing film from the sputter deposition source.
  • it is essential to perform some filtering of the beam to remove particles which degrade the coating. It may also be necessary to apply a bias voltage on the substrates to control the energy of the incoming ions.
  • the preferred deposition process for this invention is direct ion beam deposition from a silicon-containing precursor gas, which may be mixed with an inert gas.
  • a silicon-containing precursor gas which may be mixed with an inert gas.
  • the most preferred silicon-containing precursor gas is TMS, but other gases such as silane and DES may be used.
  • the inert gas may be chosen from any of the group VIII gases of the periodic table of the elements, but argon is most preferred due to its availability.
  • Hydrogen and hydrocarbon gases, including but not limited to methane, ethane, and acetylene may also be introduced into the ion source plasma along with the silicon-containing precursor gas to modify the properties of the Si-DLC coating.
  • the ion beam energy used in the Si-DLC deposition process may be in the range of approximately 20 eV to approximately 1000 eV. Ion energies in the range of about 20 eV to about 400 eV are most preferred to minimize heating of the substrate during deposition.
  • an ion assist beam may be utilized, but is not required.
  • the deposition process on the magnetic transducer or magnetic recording media substrates is terminated, the vacuum chamber pressure is increased to atmospheric pressure, and the coated substrates are removed from the vacuum chamber.
  • the Si-DLC layer may be ion beam deposited onto the wear surface of a magnetic recording media substrate immediately upon completion of deposition of the magnetic material layer in vacuum.
  • the Si-DLC coatings of the present invention which are direct ion beam deposited from precursor gases, are characterized by the following features: Nanoindentation hardness in the range of about 12 GPa to about 19 GPa, compressive stress in the range of about 0.4 GPa to about 1.8 GPa, Raman spectral G-peak position in the range of about 1463 cm " ' to about 1530 cm ', a silicon concentration in the range of about 1 atomic % to about 30 atomic % .
  • Ion beam deposited Si-DLC materials of the present invention which contain hydrogen typically exhibit a hydrogen concentration in the range of about 25 atomic % to about 47 atomic % .
  • the Si-DLC coatings which are deposited by other methods are characterized by the following broader range of characteristics: a Nanoindentation hardness in the range of about 12 GPa to about 70 GPa, a compressive stress in the range of about 0.4 GPa to about 10 GPa, Raman spectral G-peak position in the range of about 1425 cm “1 to about 1530 cm “1 and a silicon concentration in the range of about 1 atomic % to about 45 atomic % .
  • Examples Examples 1-4 illustrate the characteristics of the ion beam deposited DLC coatings of Knapp et al. in copending application Serial No.
  • Examples 5-12 and the discussion which follows further illustrate the characteristics of the ion beam deposited Si-DLC coatings and superior performance of the ion beam Si-DLC-coated products of the method of this invention.
  • Si-DLC coatings were deposited by direct ion beam deposition, using a precursor gas containing an organosilicon compound.
  • IBM 3380-type, 100% size magnetic head sliders were coated with ion beam deposited DLC.
  • Seagate Barracuda 4 50% size thin film inductive nanosliders with NiFe pole pieces and an Al 2 O 3 -TiC air bearing body were coated with ion beam deposited Si-DLC and DLC.
  • Example 5-9 the DLC and Si-DLC coatings were ion beam deposited onto the wear surface of the transducer which faces the magnetic recording medium.
  • Example 10 CoCrTa magnetic recording disks were coated with ion beam deposited Si-DLC and DLC.
  • Si-DLC coatings were ion beam deposited onto the wear surface of a magnetic recording disk which faces the magnetic transducer.
  • Example 12 demonstrates that adherent, hard ion beam Si-DLC coatings can be manufactured by an ion beam sputter deposition process. The examples are for illustrative pu ⁇ oses and are not meant to limit the scope of the claims in any way.
  • Example 1 An Al 2 O 3 .TiC slider (IBM 3380-type) was coated with ion beam deposited DLC by the following method.
  • the sliders already mounted onto their suspension system were first chemically cleaned with isopropanol and blown dry with nitrogen.
  • the cleaned sliders were then attached to a 6-inch diameter graphite plate using adhesive tape.
  • the graphite plate was then mounted onto a rotary stage, and the vacuum chamber was evacuated to a pressure of 4.8 x 10 '6 Torr.
  • the slider was then sputter-etched using an argon ion beam from an 11 cm Kaufman-type ion source at an energy of 500 eV with a beam current of 137 mA for 2 minutes.
  • the etch rate of a silicon witness coupon under these conditions was approximately 300 A/minute.
  • a 1000 eV, 100 mA argon ion beam was used to sputter-deposit a 25 A thick layer of silicon by ion beam sputter deposition from a silicon target.
  • a 100 A thick DLC layer was deposited by direct ion beam deposition using the 11 cm Kaufman-type ion source, operated at a beam energy of 75 eV and a beam current of 175 mA.
  • Example 3 An Al 2 O 3 -TiC slider (IBM 3380-type) was coated with ion beam deposited DLC by the same procedure as in Example 1 , except the vacuum chamber was initially was evacuated to a pressure of 5.0 x 10 "6 Torr, and the thickness of the DLC coating was 50 A.
  • Example 3 An Al 2 O 3 -TiC slider (IBM 3380-type) was coated with ion beam deposited DLC by the same procedure as in Example 1 , except the vacuum chamber was initially was evacuated to a pressure of 5.0 x 10 "6 Torr, and the thickness of the DLC coating was 50 A.
  • Example 3 An Al 2 O 3 -TiC slider (IBM 3380-type) was coated with ion beam deposited DLC by the same procedure as in Example 1 , except the vacuum chamber was initially was evacuated to a pressure of 5.0 x 10 "6 Torr, and the thickness of the DLC coating was 50 A.
  • a magnetoresistive tape head was chemically cleaned, and mounted in an aluminum fixture.
  • the fixture was installed in a stainless steel vacuum chamber and the chamber was evacuated to a pressure of 3.0 x 10 "6 Torr.
  • the tape head was then sputter-etched using an argon ion beam from an 11 cm Kaufman-type ion source at an energy of 500 eV with a beam current of 137 mA for 15 seconds.
  • the etch rate of a silicon witness coupon under these conditions was approximately 300 A/minute.
  • a 1500 eV, 50 mA nitrogen ion beam was used to sputter-deposit a 25 A thick layer of silicon nitride by reactive ion beam sputter deposition from a silicon target.
  • a 225 A thick DLC layer was deposited by direct ion beam deposition using the 11 cm Kaufman-type ion source, operated at a beam energy of 75 eV and a beam current of 50 mA.
  • Example 4 Analog tape heads were cleaned with isopropanol and then blown dry with nitrogen gas. The samples were mounted in an aluminum fixture and the fixture was installed into a stainless steel vacuum chamber which was evacuated to a pressure of 4.6 x 10 "6 Torr. The tape heads were then sputter-etched for one minute using a 500 eV, 137 mA argon ion beam generated by an 11 cm Kaufman type ion source. The etch rate of a silicon witness coupon under these conditions was approximately 300 A/minute.
  • a 1000 eV, 100 mA argon ion beam was used to sputter-deposit a 200 A thick layer of amo ⁇ hous silicon by ion beam sputter deposition from a silicon target.
  • a 1200 A thick DLC layer was deposited onto the tape heads by direct ion beam deposition using the 11 cm Kaufman-type ion source, operated at a beam energy of 75 eV and a beam current of 100 mA.
  • the outstanding durability and performance enhancements due to these ion beam deposited DLC coatings were determined by performing two types of accelerated wear tests: a constant speed drag test, and a contact-start-stop (CSS) test.
  • the CSS test is used by the magnetic disk recording industry as the ANSI standard method.
  • a typical mode of failure in the tests is buildup of friction with revolutions of drag or cycles of CSS. For uncoated sliders, the friction starts at a coefficient level of approximately 0.2 and builds up to three or four times that initial value with several thousand cycles. The high levels of friction cause particle pullout with resulting abrasive wear and failure of the head-disk interface.
  • Uncoated and ion beam DLC-coated sliders were measured on a standard tester developed by Hewlett Packard Laboratories, which consists of a computer-controlled spindle on which the disk is clamped and the slider-suspension assembly is attached to a strain gauge instrumented load beam to measure normal and frictional forces on the slider. Tests were conducted in a class 100 clean hood in room air at 28°C and 35% relative humidity. Standard commercially available 95 mm diameter thin film disks with a 200-300 A thick layer amo ⁇ hous carbon and a 20 A thick layer of lubricant were used in the tests.
  • TDV touch-down velocity
  • the tester was programmed to perform either slow speed drag tests or CSS tests while taking one-revolution friction data periodically, at 100 cycle intervals. These data are averaged, and the result is plotted as a function of revolutions along with the TDV.
  • An example of drag test data for an uncoated IBM 3380-type Al 2 O 3 -TiC slider is presented in FIG. 2A, and 2B, and an example of CSS test data for an uncoated IBM 3380-type Al 2 O 3 -TiC slider is presented in FIG. 2C and 2D.
  • the frictional force started at 2.07 gmf and increased with the number of test revolutions to a value near 5 gmf at 800 revolutions. Then, it remained nearly constant until increasing to a maximum of 6 gmf at approximately 2600 revolutions. The test was stopped at 3300 revolutions when the TDV showed two consecutive values 50% above the lowest value, a criterion chosen to maximize the accuracy of the determination of contamination on the sliders by wear products. An increase of TDV is an indication that material has transferred from the disk to the slider.
  • the frictional force started at 1.93 gmf and increased to 5.2 gmf at approximately 300 start/stops.
  • FIG. 3B show the drag test results for a slider coated with 100 A of DLC in Example 1.
  • the test result is substantially different and improved relative to the uncoated sliders.
  • the frictional force rapidly increased from 1.61 gmf to about 3.2 gmf and remained essentially constant for 30,000 revolutions.
  • the TDV decreased from 3.51 meters/second to 2.8 m/s and remained essentially constant for the duration of the test.
  • FIG. 4 A and FIG. 4B show the drag test results for a slider coated with 50 A of DLC in Example 2.
  • the test results were nearly identical to those found in FIG. 3A and FIG. 3B for the slider coated with 100 A of DLC in Example 1. Again, there was only a very small amount of debris found on the rails of the slider for this test. The rails were much cleaner than was the case for the tests of the uncoated sliders.
  • FIG. 2C and FIG. 2D show the results of a CSS test for an uncoated Al 2 O 3 -
  • FIG. 5A and FIG. 5B show the results of CSS tests on the same slider (100 A DLC coating) used to obtain the data in FIG. 3A and FIG. 3B.
  • the data show that the frictional force increased rapidly from 1.77 gmf to approximately 3.3 gmf and remained essentially constant for 8,000 CSS cycles.
  • the TDV showed only one instance of an increase, but otherwise showed a gradual decrease over the duration of the test.
  • the uncoated sliders showed an increase of frictional force to 6 gmf by 1 ,000 cycles for three tests which were conducted.
  • the frictional force did not increase above 3.4 gmf at any time up to the point the test was terminated at 8,000 cycles.
  • the superior performance of the ion beam DLC coated sliders could be related to microscopic observations of debris on the rails of the air bearing surface.
  • the ion beam DLC coated sliders showed significantly less debris as compared to the uncoated sliders.
  • the reduced level of debris on the DLC coated sliders was most likely responsible for the superior performance.
  • Si-DLC coatings of the present invention were direct ion beam deposited onto a variety of substrate materials utilized in the fabrication of magnetic transducers and magnetic recording media, and onto the wear surfaces of magnetic head sliders for evaluation of mechanical performance and comparison to ion beam deposited DLC coatings.
  • Si-DLC coatings were ion beam deposited onto the wear surface of magnetic recording disks.
  • Si-DLC coatings were deposited onto silicon wafers for characterization of the range of material properties of the ion beam deposited Si-DLC coating materials of the present invention.
  • Si-DLC coatings were deposited by ion beam sputter deposition.
  • the argon ion beam current density at the substrates was adjusted to give an etch rate of about 30 A/minute to about 70 A/minute on a silicon witness coupon, and the sputter-etching time was approximately 1 minute.
  • the 11 cm ion beam source was also utilized for deposition of the Si-DLC and DLC materials.
  • the ion beam energy was reduced, and a silicon-containing precursor gas, tetramethylsilane (TMS), was added to the argon feed gas to initiate the deposition of the Si-DLC layer.
  • TMS tetramethylsilane
  • methane gas was added to the TMS and argon feed gases for the deposition of Si-DLC.
  • the same vacuum chamber conditions and 11 cm ion beam source were used for Examples 10 and 11.
  • the ion beam energy was reduced, and methane was added to the ion source plasma as a precursor gas, and the argon flow was shut off, to initiate the deposition of the DLC layer.
  • a 1000 eV argon ion beam was used to sputter-deposit an adhesion layer of silicon by ion beam sputter deposition from a silicon target prior to deposition of the DLC layer.
  • Example 5 For the purpose of comparative evaluation, a series of sliders mounted on HGA's were coated with Si-DLC, while some HGA's were coated with DLC using an ion beam sputter-deposited silicon adhesion layer.
  • the undoped DLC coatings were made under deposition process conditions known to produce a DLC coating with a high hardness of about 20 GPa, in order to achieve a DLC coating with maximum resistance to wear.
  • the HGA's coated with DLC and Si-DLC were subjected to nanowear tests and CSS tests.
  • the diamond tip of an atomic force microscope contacted the coated surface of the HGA's with a predetermined force, and was then moved across the surface in a prescribed pattern to cause wear of the coating.
  • This nanowear test produced two types of qualitative data which may be use for comparison of coated surfaces: wear resistance, and adhesion (whether or not the coating adhesion failed during the wear test).
  • Coated HGA's from Runs #6338, #6339, #6331, and #6332 were separated into three equivalent sets (Set 1 , Set 2, Set 3) containing four different HGA's in each set. Then, the coated HGA's were mounted in a CSS test setup similar to that used above.
  • the CSS test results for each set of coated HGA's were as follows. In Set 1 , all four coated HGA's passed 20,000 CSS cycles without any failures. In Set 2, all four coated HGA's passed 40,000 CSS cycles without any failures. In Set 3, utilizing an accelerated CSS test condition, designed to produce failure in a reduced number of CSS cycles, all four coated HGA's passed 20,000 accelerated CSS cycles without any failures.
  • the CSS and nanowear results for the ion beam deposited DLC and Si-DLC coatings on HGA's demonstrated that the Si-doped DLC coatings performed at least as well as undoped DLC protective coatings on magnetic head sliders.
  • Example 6 An HGA slider was coated with a " 100 A thick coating of Si-DLC (Run #6186) by direct ion beam deposition using a feed gas mixture of 2.7 seem TMS and 12 seem methane, an ion beam voltage of 200 V, and an angle of incidence of the beam onto the substrates of about 10 degrees (see Table 2 in the discussion which follows). The coating was adherent, and free from delamination on all exposed surfaces of the HGA slider.
  • Another HGA slider was coated with a " 500 A thick coating of Si-DLC (Run #6179) by direct ion beam deposition using increased deposition time, but otherwise the same process conditions as in Run #6186.
  • NiFe is a material used in magnetic pole pieces of a slider; FeSiAl is another material commonly used in magnetoresistive heads.
  • CoCrTa is a common magnetic recording disk material.
  • Al 2 O 3 is a common electrical insulator material used around the electrically conductive head material on a magnetic transducer.
  • Al 2 O 3 -TiC is a common material used in the body and air bearing surfaces of magnetic head sliders.
  • Si-DLC and DLC coatings were ion beam deposited onto the wear surfaces of sliders on HGA's and onto specially prepared sample coupons.
  • thin films of each magnetic material were deposited onto stainless steel coupons by argon ion beam sputter deposition from a metal alloy target.
  • the following metal target materials were used: pure Ni; Ni with 19 wt. % Fe for the deposition of NiFe; Fe with 10 wt. % Si and 6 wt. % Al for the deposition of FeSiAl; Co with 8 atomic % Cr and 4 atomic % Ta for the deposition of CoCrTa.
  • Highly polished Al 2 O 3 -TiC and stainless steel coupons were also utilized as substrates.
  • the adhesion of the Si-DLC and DLC coatings on the magnetic material substrates was evaluated by three methods: (i) optical microscopic inspection of the coating immediately after completion of the coating process, (ii) optical microscopic inspection after completion of a boiling water-to-ice water thermal shock test (conditions as discussed in Example 6), and (iii) a tensile pull adhesion test with a Sebastian II adhesion tester.
  • a tensile pull adhesion test an aluminum pull stud of known contact area is first attached to the surface of a coated sample by epoxy.
  • the pull stud attached to the specimen is mounted into the Sebastian II tester, and a force is applied to the stud in a direction pe ⁇ endicular to the specimen surface in an effort to separate the stud from the specimen.
  • the stud is pulled with increasing force until separation occurs.
  • the force at which separation of the stud and specimen occurs is recorded. If the stud separates from the specimen due to disbonding at the interface between the substrate and the coating, then the recorded force is a measurement of the adhesion strength of the coating to the substrate. If separation occurs within the epoxy, within the substrate, within the bulk of the coating, or if the epoxy disbonds from the surface of the coating, then the adhesion strength between the substrate and the coating is greater than the recorded force.
  • A polished Al 2 O 3 -TiC coupon
  • B stainless steel
  • C Al 2 O 3 insulator material around conductive head material on slider of HGA
  • D NiFe pole pieces on slider of HGA
  • E Al 2 O 3 -TiC air bearing and body material of slider of HGA
  • G all materials on exposed slider surfaces of HGA.
  • NiFe, FeSiAl, CoCrTa used in magnetic transducers and magnetic recording media.
  • the bond strength between the Si-DLC coating and the substrate was greater than or equal to 10 kpsi (the cohesive strength of the epoxy due to the curing conditions utilized) for each of the magnetic metallic materials tested.
  • the adhesion of the Si-DLC coating (Run #6385) to stainless steel was also excellent, and exceeded the cohesive strength of the epoxy.
  • the DLC coating without an adhesion layer (Run #6386) on stainless steel spalled either during deposition or immediately upon removal from the coating chamber. The adhesion of the DLC coating (without an adhesion-enhancing interlayer) was poor on all of the metal substrates tested.
  • metallic materials e.g. Ni, NiFe, FeSiAl, CoCrTa
  • ceramic materials e.g.
  • Al 2 O 3 and Al 2 O 3 -TiC used in magnetic head sliders and other transducers and magnetic recording media without the need for an adhesion layer. Because of their inherent chemical resistance, and demonstrated outstanding adhesion, the Si-DLC coatings of the present invention impart outstanding corrosion resistance to the magnetic materials used in magnetic transducers and recording media.
  • Example 8 A highly polished stainless steel coupon, and a slider mounted in an HGA were coated with an adherent DLC coating using a thin layer (about 30 A) of Si-DLC as an adhesion layer. After chemical cleaning and mounting in the vacuum chamber, the substrates were sputter-etched with an argon ion beam under conditions which produced an etch depth of about 130 A on a silicon witness coupon. Next, the deposition conditions summarized in Table 3 (Run # 6198) were utilized for the deposition of an Si-DLC layer, followed by a DLC layer. Table 3
  • the adhesion test results are also summarized in Table 3.
  • the coatings on the stainless steel coupon and slider surfaces of the HGA passed the thermal shock adhesion test.
  • the tensile bond strength of the coating to the stainless steel coupon, as determined by the pull test was greater than 12.7 kpsi, the value at which cohesive failure occurred within the epoxy. Because of the small size of the slider on the HGA, a pull test could not be conducted.
  • Example 9 A series of coating runs was performed to investigate the effect of the silicon concentration in the ion beam deposited Si-DLC material on the adhesion of this coating to the wear surfaces of magnetic head sliders. The goal was to determine the minimum concentration of silicon in the ion beam deposited Si-DLC material required to achieve an adherent coating without an adhesion layer.
  • the run conditions, and adhesion test results are presented in Table 4.
  • the values of the approximate Si atomic concentration presented in Table 4 are based on the results of measurements of films deposited under similar conditions (see Table 6 in the discussion which follows).
  • Si-DLC films containing 5.2 atomic % Si and 6.7 atomic % Si showed no sign of delamination from the slider surfaces either before or after the thermal shock adhesion test.
  • the 200 A thick Si-DLC coating made with a Si concentration of 5.2 atomic % (Run #6576) displayed partial delamination before the thermal shock test, and further delamination after the thermal shock test. Loss of adhesion for thicker coatings is the result of the compressive stress in the coatings. Therefore, for low Si atomic concentrations in the Si-DLC material, the coating adhesion is improved by reducing the coating thickness.
  • this reduced coating thickness is one of the key objectives of the Si-DLC coating material of the present invention.
  • a typical coating thickness is less than about 100 A, and preferably less than about 50 A. Therefore, the results indicate that an atomic Si concentration of less than or equal to about 5 % results in sufficient adhesion of the ion beam deposited Si-DLC material to magnetic head sliders. Furthermore, as the coating thickness is reduced, even lower Si concentrations are required for sufficient adhesion. For example, for a 20 A thick Si-DLC coating applied to magnetic transducers and media, the inventors believe that a Si concentration as low as about 1 atomic % will result in an adherent ion beam deposited Si-DLC coating.
  • Example 10 Two deposition runs were conducted for the pu ⁇ ose of comparing the adhesion of the ion beam deposited Si-DLC coatings and DLC coatings to the surface of magnetic recording disks. Substrates for this evaluation were standard magnetic recording disks, with a CoCrTa magnetic alloy (typically cobalt with 8 atomic % chromium, and 4 atomic % tantalum), except the surface of the disks was not coated with the standard hard carbon coating. The disks were packaged in an air tight container immediately upon completion of the deposition of the magnetic material to minimize contamination, so that no chemical cleaning was required prior to ion beam deposition of DLC or Si-DLC.
  • CoCrTa magnetic alloy typically cobalt with 8 atomic % chromium, and 4 atomic % tantalum
  • a short ion beam sputter-etch was performed to remove oxide material that formed on the disk surface due to exposure of the metal surface to air.
  • one half of the disk was coated with a 300 A thick coating of Si-DLC by direct ion beam deposition (Run #6497, ion beam voltage of 350 Volts, 3.6 seem TMS + 5 seem Ar gas flow to the 11 cm gridded Kaufman-type ion beam source).
  • the ion beam deposited Si-DLC coating on the disk was uniform, low friction, and smooth.
  • the magnetic layer would not be exposed to air or contaminants prior to deposition of the Si-DLC coating.
  • the results in this example clearly show that if the surface of the magnetic material becomes contaminated, the ion beam deposited Si-DLC coating can be made to adhere by use of an ion beam sputter-etch step prior to deposition of the Si-DLC layer.
  • Example 11 Si-DLC was ion beam deposited using different process conditions such as ion beam voltage, precursor gas composition, and deposition angle (angle of incidence of the ion beam on the substrates).
  • This example presents a summary of some of the representative properties of the ion beam deposited Si-DLC materials of the present invention as a function of various process conditions.
  • Tables 5, 6, 7 and 8 and FIGS. 6-14 illustrate the dependence of Si-DLC material hardness, stress, elemental composition, and chemical bonding structure (as evidenced by Raman spectroscopy) on the ion beam voltage, precursor gas composition, and deposition angle using the ion beam deposition process of the present invention.
  • the measured nanoindentation hardness values were independent of the substrate hardness.
  • the instrument allows for correction of the hardness value for elastic recovery during the indentation. Since the Si-DLC materials exhibit significant elasticity, this hardness measurement technique is required to obtain accurate hardness values. This method also provides a measurement of Young's modulus of the Si-DLC materials.
  • the nanoindentation hardness values were scaled to a reference hardness value of 11.6 which was obtained for the Si(100) wafer substrates. The uncertainty in the nanoindentation hardness values is approximately - /-10%.
  • the compressive stress of the Si-DLC coating materials was measured by the wafer curvature method using an FSM, Inco ⁇ orated stress meter.
  • the FSM instrument measures the bow imparted to a Si(100) wafer substrate by the coating material and calculates the coating stress using Poisson's equation (thin film assumption) based on the measured coating thickness (determined by surface profilometry), the wafer thickness and the known elastic properties of the wafer.
  • the elemental composition of the Si-DLC materials was measured by Rutherford Backscattering Spectrometry (RBS) and Hydrogen Forward Scattering (HFS) Analysis.
  • RBS Rutherford Backscattering Spectrometry
  • HFS Hydrogen Forward Scattering
  • a beam of high energy helium ions bombards the coated samples.
  • Helium ions are scattered from the beam by the sample, and hydrogen is forward scattered from the sample.
  • the composition of the coating can be determined.
  • the uncertainty in the atomic concentrations as determined by these methods is approximately +1- 0.4 atomic % for argon, approximately +1-2 atomic % for silicon, approximately +1-1 atomic % for carbon, and approximately +/-10 atomic % for hydrogen.
  • the Raman spectral signal is a measurement of the interaction of photons from an incident laser beam with the vibrational modes of a material lattice. These vibrational modes are determined by the chemical bonding in the material structure. The interaction causes the wavelength of the laser light to be shifted. Therefore, the Raman spectral signal is a signature of how the atoms in the Si-DLC material are chemically bonded. This information is complementary to the elemental analysis which determines only the concentration of elements which are present in the sample. DLC materials exhibit a characteristic peak in the Raman spectrum known as the G-peak.
  • the position of the G-peak is commonly used to characterize and differentiate DLC materials.
  • the discussion which follows clearly shows how the shape of the Raman peaks and the position of the Raman G-peak can differentiate the ion beam deposited Si-DLC materials from DLC, and can characterize the range of chemical bonding in the Si-DLC materials of the present invention.
  • Raman spectroscopy The effect on the silicon dopant on the chemical bonding structure of ion beam deposited DLC materials was investigated with Raman spectroscopy.
  • Raman spectra for representative DLC (Run #6304, 12 seem CH4 feed gas, ion beam voltage of 150 Volts) and Si-DLC (Run #6285, 3.6 seem TMS plus 5 seem Ar feed gas, ion beam voltage of 350 Volts) and materials are presented in FIGS. 6 and 7, respectively. These present the Raman spectral scans (raw data), the curve fit to the raw data, the background subtraction, and deconvoluted Gaussian peaks used to fit the raw data.
  • Si-DLC materials is certainly significant, and illustrate that the presence of silicon in the material has had a significant influence on the chemical bonding structure.
  • Table 5 and FIGS. 8 and 9 present the effect of ion beam voltage on the film properties.
  • the precursor gas composition for all the deposition runs in Table 5 was 3.6 seem TMS and 10 seem argon, except for Run #6195, which utilized 3.6 seem TMS and 6 seem argon.
  • hardness data is plotted as closed in squares and stress data is potted as open squares.
  • Higher ion beam voltage causes the ions to impact the surface of the substrate with higher energy.
  • the hardness and stress increase as a function of increasing ion beam voltage.
  • the hardness and stress are fairly constant, up to an ion beam voltage of 650 V, the maximum voltage studied.
  • the very similar dependance of hardness and stress as a function of ion beam voltage was also found for ion beam deposited DLC.
  • the lower hardness of Si-DLC at low ion beam voltage is attributed to lack of sufficient impact energy required to form the diamond-like chemical bonds which maximize the hardness of the material.
  • the hydrogen content of the Si-DLC material appears to decrease and the carbon content increases with increasing beam voltage. This trend is also similar to that found for ion beam deposited DLC and is attributed to removal of hydrogen by sputtering at higher impact energy.
  • the argon content of the Si-DLC materials increases with increasing beam voltage. This is likely due to increased implantation of argon into the near-surface of the growing Si-DLC film as the impact energy
  • Si-DLC material is controlled more by the precursor gas mixture than by the ion beam impact energy.
  • the Raman G-peak shift shows a small, but systematic rise from 1463 cm "1 to 1475 cm '1 as the ion beam voltage is increased.
  • Table 6 shows the effects of varying the precursor gas composition by changing the argon flow between 5 and 20 seem while maintaining the TMS flow at
  • the Si-DLC hardness and stress increased with decreasing argon flow rate. This suggests that decreasing the argon flow to zero and utilizing a precursor gas feed of only TMS would further increase the hardness.
  • the increase in hardness expected for zero Ar flow is expected to be on the order of only 0.5 GPa or less.
  • increasing the argon flow rate had no significant effect on the Raman G-peak position or the elemental composition of the Si-DLC materials, except for an increase in the concentration of entrapped argon in the film.
  • Run utilized an ion beam energy of 75 Volts. All other coating runs utilized an ion beam energy of 200 Volts.
  • hardness data is plotted as filled in squares and stress data is potted as open squares.
  • the hardness of the Si-DLC coatings made with TMS are about 2 to 3 GPa less than the hardness of DLC coatings (deposited without TMS).
  • the hardness of the Si-DLC coatings is not strongly influenced by TMS flow rate over the range of flow rates presented in Table 7. All of the Si-DLC coatings are in compressive stress. The value of the compressive stress of the Si-DLC materials generally decreases as the TMS flow rate is increased.
  • the atomic concentrations of carbon (closed squares), hydrogen (closed triangles), silicon (plus symbols), and argon (X symbols) in Si-DLC are plotted as a function of TMS flow rate added to 12 seem methane.
  • the elemental composition data show that the silicon concentration in the coating material increases from 0 atomic % to 12 atomic % as the TMS flow is increased from 0 seem to 2.7 seem.
  • the hydrogen concentration in the Si-DLC material decreases, while the atomic concentrations of carbon and argon content are fairly constant as a function of TMS flow rate.
  • the Raman spectroscopy results show a large and continuous decrease in the G-peak position with increasing TMS flow.
  • FIG. 13 and FIG. 14 show the effect of the deposition angle (i.e. angle of incidence between the impinging ion beam and the substrate surface) on material properties of ion beam deposited Si-DLC and DLC.
  • the orientation of the ion beam source and the distance between the ion beam source and the substrates was the same for the deposition of the Si-DLC and DLC materials.
  • hardness data is plotted as closed squares
  • stress data is plotted as open squares. For both materials, the hardness and stress are essentially constant as a function of angle at the lower angles but then decrease rapidly as a function of deposition angle above a critical angle.
  • This critical angle for DLC is between about 40 degrees and about 50 degrees.
  • the critical angle for Si-DLC is between about 60 degrees and about 67 degrees.
  • the critical angle for the stress and hardness appear to be the same.
  • the critical angle for the stress and hardness appear to be the same.
  • the DLC hardness is linearly related (i.e. directly proportional) to the stress of DLC.
  • the Si-DLC hardness is linearly related (i.e. directly proportional) to the stress of Si-DLC.
  • NIL degrees' (A) (A/min) (GPa) (GPa) (atomic %,) (cm '1 ).
  • the elemental composition of the Si-DLC materials is approximately 41.3 atomic % carbon, 15 atomic % silicon, 43 atomic % hydrogen, and 0.7 atomic % argon.
  • the significant change is the decrease of the silicon concentration from 19.5 atomic % to 15 atomic % , and the increase in hydrogen concentration from 37 atomic % to 43 atomic % .
  • the Raman G-peak position was essentially unaffected by the change in deposition angle.
  • the Raman G-peak position although sensitive to changes in precursor gas mixtures (see Table 7), is not sensitive to small changes in the silicon concentration (or coating hardness and stress) which are associated with changes in deposition angle.
  • Example 12 Si-DLC coatings were deposited onto polished stainless steel coupons, polished Al 2 O 3 -TiC coupons, silicon wafers, and the magnetic transducers on HGA's by argon ion beam sputter deposition in Runs #6387 and #6389.
  • a 1000 eV, 50 mA argon ion beam generated by a 5 cm gridded Kaufman- type ion beam source was used to sputter-deposit the Si-DLC layer by ion beam sputter deposition from a silicon carbide target.
  • the deposition rate of the Si-DLC coating was approximately 28 A/minute, and the compressive stress was 1.2 x 10 10 GPa.
  • the prior examples illustrate ion beam deposited Si-DLC coatings with silicon concentrations between about 5 atomic percent and about 46 atomic percent.
  • the lower limit of the useable silicon concentration is the silicon concentration which is required to promote good adhesion of the Si-DLC coating.
  • the adhesion of the Si-DLC coating is dependent on the silicon concentration, and substrate material. Because the Si-DLC coatings are under internal compressive stress, the adhesion strength of the Si-DLC coatings improves as the coating thickness is reduced. Therefore, as the magnetic spacing, i.e. Head-to-disk flying height, is reduced, the necessary silicon concentration in the Si-DLC coating may be reduced.
  • the upper limit of the silicon concentration in the ion beam deposited Si-DLC materials of the present invention is determined by the ability of the DLC matrix to isolate silicon atoms, as previously discussed.
  • the silicon-to-carbon ratio becomes one, the deposited material takes on characteristics of silicon carbide.
  • the silicon-to-carbon ratio exceeds one, free silicon remains in the material. Both of these cases are detrimental to the head-disk interface. Therefore, the upper limit of the silicon-to-carbon ratio is about 0.95 for Si-DLC materials with low hydrogen content (such as those deposited by ion beam sputter deposition, deposition from a laser ablation ion source or a cathodic arc ion source), and preferably less than or equal to about 0.9 as described in Example 12.
  • Example 5 The CSS and nanowear results of Example 5 for ion beam deposited Si-DLC and DLC coatings on HGA's, demonstrated that the Si-DLC coatings of the present invention performed equal to or better than DLC as protective coatings for magnetic head sliders.
  • Examples 7 and 8 showed that DLC does not adhere well to NiFe and FeSiAl without an adhesion layer, thus demonstrating that the Si-DLC materials of the present invention have superior adhesion without the need for an adhesion layer.
  • Example 10 illustrated the Si-DLC coatings of the present invention applied to magnetic recording media.
  • Representative material characteristics of the ion beam deposited Si-DLC coatings of the present invention include the following: Nanoindentation hardness in the range of about 12 GPa to about 19 GPa, compressive stress in the range of about 0.4 GPa to about 1.8 GPa, Raman spectral G-peak position in the range of about 1463 cm “ ' to about 1529 cm “1 , a silicon concentration in the range of about 1 atomic % to about 30 atomic %.
  • Ion beam deposited Si-DLC materials of the present invention which contain hydrogen typically exhibit a hydrogen concentration in the range of about 25 atomic % to about 47 atomic %.
  • Example 12 demonstrated that adherent, hard ion beam Si-DLC coatings can be manufactured by an ion beam sputter deposition process.
  • the Si-DLC coatings of the present invention impart outstanding wear resistance, and corrosion resistance to the magnetic materials used in magnetic transducers and recording media. Since an adhesion-enhancing interlayer is not required, the ion beam deposited Si-DLC coatings of the present invention can be made extremely thin (about 20 A thick), thus allowing for higher data storage densities, while maintaining outstanding wear resistance and corrosion resistance. From the foregoing description, one of ordinary skill in the art can easily ascertain that the present invention provides an improved method for producing highly protective and wear resistant Si-DLC coatings on magnetic transducers and magnetic recording media.

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Abstract

La présente invention concerne un procédé dont la première opération consiste à nettoyer chimiquement la surface d'un transducteur magnétique ou d'un substrat de support d'enregistrement magnétique de façon à en éliminer les matériaux indésirables et autres contaminants, après achèvement d'une opération de finition visant à définir la forme de cette surface. La deuxième opération consiste à introduire le substrat dans une enceinte à vide (1), et à y faire le vide d'air. La troisième opération consiste à soumettre la surface du substrat à une attaque chimique par pulvérisation au moyen d'ions chargés d'énergie de façon, d'une part à favoriser l'enlèvement de contaminants résiduels, c'est-à-dire des hydrocarbures et des oxydes de surface, et d'autre part à activer la surface. Après achèvement de l'attaque chimique par pulvérisation, on procède au dépôt d'une couche de carbone de type diamant dopé au silicium en utilisant une technique de dépôt par faisceau d'ions. Lorsque la couche de carbone de type diamant dopé au silicium atteint l'épaisseur voulue, le processus de dépôt sur les substrat est achevé, la pression de l'enceinte à vide (1) est ramenée à la pression atmosphérique, et on sort de l'enceinte à dépression les substrats revêtus de carbone de type diamant dopé au silicium.
PCT/US1997/007222 1996-09-03 1997-04-30 Revetements de carbone de type diamant dope au silicium pour transducteurs magnetiques et supports d'enregistrement magnetique WO1998010115A1 (fr)

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0962547A1 (fr) * 1998-06-05 1999-12-08 International Business Machines Corporation Système de pulvérisation par faisceau ionique
EP1052629A1 (fr) * 1999-05-13 2000-11-15 Sony Corporation Support d'enregistrement optique
US6368678B1 (en) 1998-05-13 2002-04-09 Terry Bluck Plasma processing system and method
US6404592B1 (en) * 1997-10-01 2002-06-11 Alps Electric Co., Ltd. Magnetic head producing method
EP1202264A3 (fr) * 2000-10-27 2004-06-09 Pioneer Corporation Support d'enregistrement optique
EP1437424A3 (fr) * 2002-05-31 2004-08-18 Veeco Instruments Inc. Méthode et appareillage de lissage de surfaces à l'échelle atomique
EP1521245A1 (fr) * 2003-10-03 2005-04-06 Fuji Photo Film Co., Ltd. Moyen d'enregistrement magnétique et procédé pour sa fabrication
US20090050469A1 (en) * 2007-08-22 2009-02-26 International Business Machines Corporation Alignment film forming apparatus and methos
JP2013234353A (ja) * 2012-05-08 2013-11-21 Honda Motor Co Ltd ダイヤモンド状炭素膜被覆部材およびその製造方法
US8815060B2 (en) 2004-08-30 2014-08-26 HGST Netherlands B.V. Method for minimizing magnetically dead interfacial layer during COC process
RU2681587C1 (ru) * 2018-01-22 2019-03-11 Федеральное государственное бюджетное научное учреждение "Федеральный исследовательский центр "Красноярский научный центр Сибирского отделения Российской академии наук" Способ нанесения нанопленочного покрытия на подложку
CN115125489A (zh) * 2021-03-25 2022-09-30 东莞新科技术研究开发有限公司 一种半导体表面的镀膜方法
CN116180002A (zh) * 2021-11-26 2023-05-30 东莞新科技术研究开发有限公司 半导体的镀膜方法
CN116180077A (zh) * 2021-11-26 2023-05-30 东莞新科技术研究开发有限公司 带有镀膜结构的半导体

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58150122A (ja) * 1982-03-01 1983-09-06 Nec Corp 磁気ヘツド
US4490229A (en) * 1984-07-09 1984-12-25 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Deposition of diamondlike carbon films
US4840844A (en) * 1986-06-02 1989-06-20 Hitachi, Ltd. Magnetic recording medium
US4987007A (en) * 1988-04-18 1991-01-22 Board Of Regents, The University Of Texas System Method and apparatus for producing a layer of material from a laser ion source
US5275850A (en) * 1988-04-20 1994-01-04 Hitachi, Ltd. Process for producing a magnetic disk having a metal containing hard carbon coating by plasma chemical vapor deposition under a negative self bias
US5476691A (en) * 1994-01-21 1995-12-19 International Business Machines, Inc. Surface treatment of magnetic recording heads
US5482602A (en) * 1993-11-04 1996-01-09 United Technologies Corporation Broad-beam ion deposition coating methods for depositing diamond-like-carbon coatings on dynamic surfaces
US5508368A (en) * 1994-03-03 1996-04-16 Diamonex, Incorporated Ion beam process for deposition of highly abrasion-resistant coatings

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58150122A (ja) * 1982-03-01 1983-09-06 Nec Corp 磁気ヘツド
US4490229A (en) * 1984-07-09 1984-12-25 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Deposition of diamondlike carbon films
US4840844A (en) * 1986-06-02 1989-06-20 Hitachi, Ltd. Magnetic recording medium
US4987007A (en) * 1988-04-18 1991-01-22 Board Of Regents, The University Of Texas System Method and apparatus for producing a layer of material from a laser ion source
US5275850A (en) * 1988-04-20 1994-01-04 Hitachi, Ltd. Process for producing a magnetic disk having a metal containing hard carbon coating by plasma chemical vapor deposition under a negative self bias
US5482602A (en) * 1993-11-04 1996-01-09 United Technologies Corporation Broad-beam ion deposition coating methods for depositing diamond-like-carbon coatings on dynamic surfaces
US5476691A (en) * 1994-01-21 1995-12-19 International Business Machines, Inc. Surface treatment of magnetic recording heads
US5508368A (en) * 1994-03-03 1996-04-16 Diamonex, Incorporated Ion beam process for deposition of highly abrasion-resistant coatings

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6404592B1 (en) * 1997-10-01 2002-06-11 Alps Electric Co., Ltd. Magnetic head producing method
US6368678B1 (en) 1998-05-13 2002-04-09 Terry Bluck Plasma processing system and method
US6238531B1 (en) 1998-06-05 2001-05-29 International Business Machines Corporation Method and apparatus to improve the properties of ion beam deposited films in an ion beam sputtering system
EP0962547A1 (fr) * 1998-06-05 1999-12-08 International Business Machines Corporation Système de pulvérisation par faisceau ionique
EP1052629A1 (fr) * 1999-05-13 2000-11-15 Sony Corporation Support d'enregistrement optique
EP1202264A3 (fr) * 2000-10-27 2004-06-09 Pioneer Corporation Support d'enregistrement optique
EP1437424A3 (fr) * 2002-05-31 2004-08-18 Veeco Instruments Inc. Méthode et appareillage de lissage de surfaces à l'échelle atomique
EP1521245A1 (fr) * 2003-10-03 2005-04-06 Fuji Photo Film Co., Ltd. Moyen d'enregistrement magnétique et procédé pour sa fabrication
US8815060B2 (en) 2004-08-30 2014-08-26 HGST Netherlands B.V. Method for minimizing magnetically dead interfacial layer during COC process
US20090050469A1 (en) * 2007-08-22 2009-02-26 International Business Machines Corporation Alignment film forming apparatus and methos
US9034151B2 (en) * 2007-08-22 2015-05-19 International Business Machines Corporation Alignment film forming apparatus and method
US9869014B2 (en) 2007-08-22 2018-01-16 International Business Machines Corporation Formation of an alignment film for a liquid crystal on a substrate
JP2013234353A (ja) * 2012-05-08 2013-11-21 Honda Motor Co Ltd ダイヤモンド状炭素膜被覆部材およびその製造方法
RU2681587C1 (ru) * 2018-01-22 2019-03-11 Федеральное государственное бюджетное научное учреждение "Федеральный исследовательский центр "Красноярский научный центр Сибирского отделения Российской академии наук" Способ нанесения нанопленочного покрытия на подложку
CN115125489A (zh) * 2021-03-25 2022-09-30 东莞新科技术研究开发有限公司 一种半导体表面的镀膜方法
CN116180002A (zh) * 2021-11-26 2023-05-30 东莞新科技术研究开发有限公司 半导体的镀膜方法
CN116180077A (zh) * 2021-11-26 2023-05-30 东莞新科技术研究开发有限公司 带有镀膜结构的半导体

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