JP4483243B2 - Film, method for forming the same, and semiconductor device and method for manufacturing the same - Google Patents

Description

  [Technical Field] The present invention relates to a film that can be used for electronic devices and other applications utilizing the functional property of semiconductor properties of a self-assembled monolayer (SAM), a method for forming the same, a semiconductor device provided with the film, and a method for manufacturing the same About.

  In recent years, research on molecular electronics has progressed, and the confirmation of the principle of electronic devices utilizing the properties of individual molecules has been reported. For example, in M, A <Reed, et al Appl. Phys. Lett. 78 (2001) 3735, a functional molecule is a basic unit element, and self-assembled on a solid electrode substrate to form a two-dimensional self-assembled monolayer. (Self-assembled Monolayer: SAM) Attempts to develop device functions, or embed electronically functional molecules in SAMs composed of non-functional alkyl chains. Research has also been reported on measuring device characteristics of a single molecule with an STM chip or the like (Non-patent Document 1).

  If an electronic device that depends on the physical properties of these molecules alone can be produced, it is possible to design and create a much smaller device configuration unlike existing inorganic electronic devices. For example, a device can be easily manufactured by a micro liquid process in which a liquid molecule is dissolved in a solvent, a micro solution is made by an inkjet (IJ) technique, and the micro solution is used for forming a thin film.

  In addition, these methods can be made from an organic material, so that it is very easy to design a molecular material suitable for each application and purpose, and there is a possibility that a tailor-made microelectronic device can be freely produced and used. Currently, the application of ultra-microchips called muchips is expanding rapidly, and enormous demand is expected with the arrival of the ubiquitous society. The organic monomolecular structure has a great potential as the ultimate form of electronic devices in the manufacture of ultra-microchips.

However, the conventional monomolecular device structure has a big problem. First, the monomolecular film device has a structure that is based on a monomolecular film and is very fragile and easy to create a defect. Etc. were difficult to obtain with good reproducibility. In addition, it has been technically very difficult to reproducibly manufacture a dense nanostructure such as a monomolecular film (Z, J, Donhauser et al Science 292 (2001) 2303: Non-Patent Document 2, Ishida Takao Surface Science vol.24, No.2, pp83-89 (2003): Non-Patent Document 3). The current structure of monomolecular film devices has a problem in that it is difficult to distinguish the characteristics at the molecular film level from the leakage current between the electrodes. Furthermore, at present, there is a problem that there is no effective detection means other than the scanning probe microscope with respect to the characteristics at the molecular film level.
M, A <Reed, et al Appl. Phys. Lett. 78 (2001) 3735 Z, J, Donhauser et al Science 292 (2001) 2303 Takao Ishida Surface Science vol.24, No.2, pp83-89 (2003) Also, in recent years, it has been desired to design and fabricate semiconductor devices with simple equipment under mild conditions for the environment. .

  Accordingly, an object of the present invention is to provide a film that can be used for electronic devices and other applications that take advantage of the functional property of SAM, which is semiconducting.

  Another object of the present invention is to provide a method for producing a film that can be used for electronic devices and other applications under mild conditions with respect to the environment and with simple equipment.

  As a result of earnest research, the present inventor has found that a film formed by combining metal particles and a self-assembled monolayer can achieve the above-mentioned object.

The present invention has been made on the basis of the above knowledge, and includes [1] a plurality of metal particles, and a self-assembled monolayer film covering each of the plurality of metal particles, and the self-assembled monomolecule The plurality of metal particles coated on the film are aggregated, each of the plurality of metal particles is silver or copper, and the self-assembled monolayer is CF ₂ (CF ₂ ) ₇ CH ₂ CH ₂ Provided is a film formed by self-assembling any one of Si (OEt) _{3 and} CH ₃ (CH ₂ ) _n SH (n = 5 to 17) on the plurality of metal particles. Is.

The present invention also provides: [2] The film according to [1], wherein the metal particles have a particle diameter of 1 nm to 1000 nm: [3] A semiconductor element forming a channel region between source and drain electrodes in a semiconductor element The film according to any one of [1] and [2], which is used as a film: [4] a step of forming a self-assembled monolayer on the surface of a plurality of metal particles, and the self-assembled monomolecule Applying a dispersion of a plurality of metal particles coated with a film to a surface to be coated by an inkjet method or a method using a dispenser, each of the plurality of metal particles being silver or copper, in the step of forming the self-assembled monolayer on the surface of each of the plurality of metal _{particles, CF 2 (CF 2) 7} CH 2 CH 2 Si (OEt) 3 to each of the plurality of metal particles A method for forming a film characterized by self-assembly: [5] A dispersion in which a plurality of metal particles coated with the self-assembled monolayer is dispersed in an organic solvent is used as the dispersion. [4] The film formation method according to [4]: [6] The film formation method according to [4] or [5], wherein the solid content concentration of the dispersion is 20 to 60 wt%: [7] The above [1] A semiconductor device comprising at least the film according to any one of [3] to [3]: [8] The semiconductor device according to [7], comprising the film between source and drain electrodes: [9] A semiconductor device manufacturing method using at least the film forming method according to any one of [4] to [6]. Are provided respectively.

〔film〕
Hereinafter, the film | membrane of this invention is demonstrated based on the preferable embodiment.

  As described above, the film of the present invention includes a plurality of metal particles and a self-assembled monomolecular film (SAM) formed by coating each of the plurality of metal particles.

  Since the present invention has such a configuration, it can provide a film that can be used for electronic devices such as a semiconductor element utilizing the functional property of semiconductor properties of SAM, such as a semiconductor element.

  In the film of the present invention, the self-assembled monolayer film covers each of the plurality of metal particles, and the thickness, state and degree of the coating are not particularly limited as long as the effects of the present invention are not impaired. For example, the entire surface of the metal particle may be covered with a self-assembled monolayer, or only a part of the surface of the metal particle may be covered with a self-assembled monolayer as long as the semiconductor characteristics of the SAM can be obtained. It may be what you have.

  The metal particles used in the present invention are particularly preferably metal nanoparticles having good conductivity that can be densely and densely aggregated.

  As a particle size of a metal particle, 1-1000 nm, especially 10-100 nm are preferable.

  In addition, the metal particles are not particularly limited by the type, but in particular, one or more selected from the group consisting of gold, silver and copper in that the synthesis conditions are easy to optimize and can be supplied at low cost. The conductive metal particles are preferable.

  As a material for forming the self-assembled monolayer (SAM) used in the present invention, functional organic molecules are used.

  Here, the self-assembled monomolecular film refers to an organized film that is spontaneously formed simply by immersing a material for forming a film in a solution of a target molecule.

  Examples of the organic functional molecule for forming a self-assembled monolayer include, for example, a molecule having an alkyl group (fluoroalkyl group) all or part of which is substituted with fluorine, a molecule having a thiophene derivative skeleton, and a phenylene skeleton. Or a molecule containing both of them.

  Such an organic functional molecule has a functional group that can be bonded so as to form a self-assembled monolayer with metal particles. The functional group is selected according to the relationship with the type of metal particles used. Examples of the functional group capable of binding to the metal particle in the organic functional molecule include a thiol group (—SH), a disulfide group (—SS—), a silyl group (—Si—), and the like.

Specific examples of particularly preferred organic functional molecules include CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ Si (OEt) ₃ , CH ₃ (CH ₂ ) _n SH, n = 5-17, and the like.

  In the film of the present invention, it is preferable that a plurality of metal particles are aggregated through a self-assembled monomolecular film, particularly in terms of easy control of electron transfer between fine particles. Furthermore, it is preferable that the plurality of metal particles are aggregated in a hexagonal close-packed state or a state close thereto in that the functional characteristics of the self-assembled monolayer are further utilized.

  The film of the present invention preferably has a film thickness of about 20 to 50 mm.

  The film of the present invention is not particularly limited to its application and can be applied to various applications. In particular, the film is preferably used as an electronic device film, particularly as a semiconductor element film.

  Specifically, it can be applied as a film for forming a circuit region of an electronic device, a wiring film, or a channel region between source and drain electrodes in a semiconductor element.

  In particular, the film of the present invention is preferably applied to a transistor structure such as a TFT.

(Method for forming film)
The method for forming a film according to the present invention is a preferred method for forming the film described above,
Forming a self-assembled monolayer on the surface of a plurality of metal particles;
Applying a dispersion of a plurality of metal particles coated with the self-assembled monolayer to a surface to be coated by an inkjet method or a method using a dispenser;
At least.

  Since the formation method of the present invention has such a configuration, it is possible to provide a film that can be used for electronic devices such as semiconductor elements and other applications under simple conditions with respect to the environment.

  For matters not specifically described in detail in the method for forming a film according to the present invention, the matters described in detail with respect to the above-described film (for example, suitable aspects of the film) are appropriately applied.

((1) Step of forming a self-assembled monolayer on the surface of a plurality of metal particles)
The plurality of metal particles used in the forming method of the present invention can be obtained by a conventionally established synthesis method. For example, in the case of synthesizing metal nanoparticles as metal particles, a wet or dry synthesis method can be adopted (see CMC Publishing; 2002 “Latest Technology of Nanoparticle Production, Application, and Equipment” page 9).

  When employing a wet synthesis technique, for example, metal nanoparticles can be synthesized as in the following reverse micelle method.

  That is, in the reverse micelle method, using a dispersion liquid in which minute water droplets of about 10 nm are dispersed in an organic solvent (for example, cyclohexane, heptane, isooctane, etc.), a reaction precursor and, if necessary, the minute water droplets. By adding a surfactant or the like and causing a chemical reaction in a state where they are dispersed, metal nanoparticles are obtained.

When synthesizing silver fine particles as an example of metal nanoparticles, for example, AgNO ₃ , NaBH ₄ as a reaction precursor and Pentaethylene glycol dodecyl ether [C ₁₂ H ₂₅ (OCH ₂ CH ₂ ) ₅ OH] as a surfactant are dispersed. Cause a chemical reaction in the state. By this chemical reaction, fine Ag crystal fine particles are nucleated and grown in water droplets to form fine particles having a size defined in a reverse micelle state, and silver nano-particles are obtained.

  Next, a plurality of metal particles synthesized as described above are used to form a self-assembled monolayer on the surface of the plurality of metal particles. As a method for forming a self-assembled monolayer, for example, a plurality of metal particles, a SAM material such as an organic functional molecule capable of forming a self-assembled monolayer constituting the membrane of the present invention, an organic solvent (for example, And a method of immersing in a solution dissolved in dichloromethane or the like.

((2) Step of applying metal particle dispersion liquid to coated surface)
In this step, a dispersion of a plurality of metal particles coated with a self-assembled monomolecular film is applied to a surface to be coated by an ink jet method or a dispenser method.

  In the present invention, it is preferable to apply the dispersion liquid of the plurality of metal particles to the surface to be coated by flying and discharging by an inkjet method, in particular, because a patterned microarray device can be created.

  When applying the plurality of metal particles, it is preferable to use a dispersion liquid in which the plurality of metal particles coated with SAM are dispersed in an organic solvent. Such a dispersion is a dispersion obtained when a self-assembled film is formed by immersing a plurality of metal particles in a solution obtained by dissolving the above-described SAM material in an organic solvent (for example, dichloromethane). A dispersion liquid in which the plurality of metal particles thus prepared are dispersed in an organic solvent (for example, dichloromethane or the like) can be used as it is.

  The solid content concentration (content of a plurality of metal particles) of the dispersion to be applied is, for example, 20 to 60 wt%, desirably 30 to 50 wt%. The concentration of the dispersion can be adjusted by increasing the solid content (a plurality of metal particles) by solvent concentration. The concentration of the dispersion is preferably adjusted without lowering the dispersion state of the plurality of metal particles dispersed in the organic solvent, and can be achieved if the concentration is within the above range by the solvent concentration.

  The surface to be coated is appropriately selected according to the intended use of the film. For example, when a semiconductor element film is formed, a desired portion where a film is formed, such as a substrate such as a silicon substrate or an oxide film, is an object.

Also, a film according to the present invention, such as a semiconductor device thin film, can be easily prepared at room temperature and normal pressure by discharging by ink jet and patterning in a state where metal fine particles coated with SAM are dispersed in a liquid.
[Semiconductor device]
A semiconductor device according to the present invention includes at least the film described above. Since the semiconductor device of the present invention has such a structure, the composite amplification function of the self-organized monomolecular film formed from organic functional molecules and the metal particles such as metal nanoparticles makes the conductive amplification function of the metal particles self- It is a device with excellent performance that takes advantage of the feature of functional semiconductor properties of tissue monolayers.

  In particular, it is preferable to provide the film between the source and drain electrodes because, for example, a semiconductor device including a semiconductor element having the film as a channel region as shown in FIG. 1 can be obtained.

[Method of Manufacturing Semiconductor Device]
The method for manufacturing a semiconductor device according to the present invention includes at least the process for forming the film described above.

  According to the manufacturing method of the present invention, because of such a configuration, unlike a conventional method of manufacturing a semiconductor device, a semiconductor device can be designed and created under conditions that are mild to the environment, and the facilities are much smaller. Because it is simple, it has great potential as a desktop factory.

  In addition, according to the production method of the present invention, compared to conventional molecular device design guidelines, by the composite functionalization of self-organized monolayer formed from organic functional molecules and metal particles such as metal nanoparticles, An electronic device that makes use of the features of the conductive amplification function of the metal particles and the functional semiconductor property of the self-assembled monolayer can be produced.

  ADVANTAGE OF THE INVENTION According to this invention, the film | membrane which can be utilized for the electronic device other applications using the functional characteristic called SAM which semiconductor has has can be provided. Furthermore, according to the present invention, it is possible to provide a method for producing a film that can be used for electronic devices and other applications under mild conditions with respect to the environment and with simple equipment. Furthermore, according to the present invention, an excellent semiconductor device using such a film and a method for forming the film and a method for manufacturing the semiconductor device can be provided.

  The present invention suitably provides each of the embodiments described above, but is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention.

  Hereinafter, the present invention will be described more specifically with reference to examples of the present invention. However, the present invention is not limited to the examples.

  The first embodiment will be described with reference to FIG.

  A functional SAM is formed on the surface of conductive metal fine particles such as silver and gold. And the dispersion liquid which disperse | distributed the several metal particle in which SAM was formed in the surface to the solvent is discharged to the surface of the source-drain electrode patterned beforehand by the inkjet method, as shown in FIG.

  The solvent in the dispersion is dried on the surface, and agglomerated through a thin film of a thin film structure SAM, specifically a fine particle structure in which a plurality of metal fine particles with SAM formed on the surface are aggregated and solidified between the source and drain on the electrode surface. A film made of the fine metal particles is formed.

Thus, as shown in FIG. 1, a silicon substrate made of Si, an oxide film layer made of SiO ₂ , a source electrode, a drain electrode, and a gate are provided, and the film is used as a channel region between the source and drain electrodes. A semiconductor element having the same can be obtained. In this embodiment, a bottom gate type element is taken as an example, but an up gate type element capable of forming a film according to the present invention can also be formed.

  A film comprising such a composite structure network of metal particles and functional organic molecules is used as a semiconductor element film.

  As a merit of having a film according to the present invention, first, metal fine particles exist between molecular films, so that electrons can be easily injected into the molecular film from the metal, and an electric signal amplification effect can be expected.

  In addition, by using the expected single electron tunneling phenomenon such as Coulomb brocade, it is possible to perform strict micro-electric control. Furthermore, because of the current-voltage characteristics of the molecular film stack structure through metal fine particles, the instability that tends to occur in the measurement of only one molecular film is eliminated.

  Utilizing these merits, unique microtransistor physical properties can be controlled by the fine particle / SAM network formed between the source (S) and the drain (D) in the TFT element having a three-terminal structure.

  Example 2 will be described with reference to FIG.

  As shown in FIG. 2, the surface of the insulating film between the S and D electrodes is previously subjected to hydrophilic and hydrophobic two-dimensional patterning with SAM. For example, SAM-functionalized nanoparticle dispersed in a polar solvent (for example, as nanoparticle , Gold, silver, etc., and the surface of the fine particles are coated with SAM). When the liquid dispersion is ejected by inkjet, the dispersion spreads only to the hydrophilic portion along the patterning, and the dispersed nano-particles are also liquid. Arrange along the wetting.

In the patterning, as shown in FIG. 2, FAS-SAM is formed on the entire surface of Si. FAS-SAM is a SAM formed of CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ Si (OEt) ₃ . By applying UV irradiation to the SAM through a mask (UV patterning), hydrophilic and hydrophobic two-dimensional patterning can be obtained. Here, the short wavelength UV of around 170 nm is used for the irradiation UV.

  After discharging by inkjet (IJ), the dispersion solvent is dried in a short time, and only the fine and solidified fine wires of the nanometal fine particles coated with the functional SAM remain on the patterned substrate.

  In this case, by further narrowing the surface patterning, it is ultimately possible to create a series of only one nanoparticle. By performing IV measurement with this one-dimensional fine particle aggregation thin wire, a molecular device utilizing the semiconductor characteristics of a monomolecular film can be realized.

  INDUSTRIAL APPLICABILITY The present invention can be used for electronic devices and other applications that can be used for electronic devices and other applications that take advantage of the functional properties of SAM, and that can be used for electronic devices and other applications under mild conditions to the environment It has industrial applicability as a film manufacturing method.

FIG. 1 is an explanatory diagram illustrating a semiconductor element including a film according to the first embodiment and a manufacturing process thereof. FIG. 2 is an explanatory diagram showing a film and its formation process according to the second embodiment.

Claims (9)

A plurality of metal particles;
A self-assembled monolayer formed by coating each of the plurality of metal particles;
Including
A plurality of the metal particles coated on the self-assembled monolayer are agglomerated,
Each of the plurality of metal particles is silver or copper,
The self-assembled monolayer is formed by self-assembling CF ₂ (CF ₂ ) ₇ CH ₂ CH ₂ Si (OEt) ₃ on the plurality of metal particles. Wherein the metal particles have a particle size of 1 nm to 1000 nm, claim 1 Symbol placement of the membrane. The film according to claim 1 or 2 , which is used as a semiconductor element film for forming a channel region between a source and a drain electrode in a semiconductor element. Forming a self-assembled monolayer on the surface of a plurality of metal particles,
Applying a dispersion of a plurality of metal particles coated with the self-assembled monolayer to a surface to be coated by an inkjet method or a method using a dispenser;
Forming a film in which the plurality of metal particles are aggregated;
Comprising at least
Each of the plurality of metal particles is silver or copper,
In the step of forming the self-assembled monolayer on the surface of each of the plurality of metal particles , CF ₂ (CF ₂ ) ₇ CH ₂ CH ₂ Si (OEt) ₃ is added to each of the plurality of metal particles. A method for forming a film, characterized by being integrated. Wherein as a dispersion, the self-organizing a plurality of metal particles coated with monolayers uses variance liquid dispersed in organic solvent, forming method of claim 4, wherein the membrane. The film forming method according to claim 4 or 5 , wherein a solid content concentration of the dispersion is 20 to 60 wt%. Wherein a at least comprising a membrane according to any one of claims 1-3. The semiconductor device according to claim 7 , comprising the film between a source and a drain electrode. The method of manufacturing a semiconductor device which at least use the method for forming a film according to any one of claims 4-6.