CN104388904A - Method for efficiently preparing Ti-Ta high-temperature memory alloy thin film - Google Patents

Abstract

A method for efficiently preparing a Ti-Ta high-temperature memory alloy thin film, the invention relates to a thin film preparation method. The invention aims to solve the problems of complex single-target sputtering process and low efficiency of the existing Ti-Ta alloy thin film. Method: take the Ta target and carry out fan-shaped hollowing treatment on the Ti target, place the Ta target at the bottom of the hollowed-out Ti target to obtain a composite target, put the composite target into the target position of the single-chamber magnetron sputtering instrument, The substrate is fixed on the sample holder, then vacuumized, argon gas is introduced, and DC magnetron sputtering is used to deposit the composite target as the cathode to obtain a Ti-Ta high temperature memory alloy film. The invention is used for a method for efficiently preparing Ti-Ta high-temperature memory alloy film.

Description

A method for efficiently preparing Ti-Ta high temperature memory alloy thin film

technical field

The present invention relates to a method for preparing a thin film.

Background technique

At present, smart materials and devices are developing in the direction of light weight, miniaturization, and integration. Thin films of memory alloys can be widely used in micro-electromechanical systems (MEMS) as micro-drivers and micro-sensors. At present, the research on memory alloy thin films mainly focuses on Ti-Ni alloy thin films. Ti-Ni alloy thin films have excellent shape memory, superelasticity and good mechanical properties, but the Ms temperature of Ti-Ni alloy thin films is lower than 100 °C. , the operating temperature of its driving components is generally lower than this temperature, and cannot be used in fire warning and protection systems, current overload protection, and driving devices in nuclear reactors. At present, memory alloy systems with high phase transformation mainly include the following concentrated Ni-Mn-Ga, Ti-Ni-Hf, Ti-Ni-Pt/Pd/Au, among which Ni-Mn-Ga, Ti-Ni-Hf and other alloy thin films Both have the problem of high brittleness, and the Ti-Ni-based high-temperature memory alloy thin film with Pd, Pt, Au and other noble metals added has a high phase transition temperature, but the cost is expensive. Ti-Ta alloy film has high plasticity, good processing performance, and is easy to process into devices, and its phase transition temperature can be changed between 100°C and 500°C by adjusting the composition, so Ti-Ta high-temperature memory alloy film can be considered as a microelectromechanical device. Micro-actuator and micro-sensor materials with great development prospects in the field. However, in the preparation process of alloy thin films, alloy targets are often used to obtain thin films by sputtering, and Ta is a refractory metal, so it is very difficult to melt Ti-Ta alloys, and one alloy target can only be used to prepare Ti-Ta with a specific composition. Ta alloy thin film, the process is complicated and the efficiency is low.

Contents of the invention

The invention aims to solve the problems of complex single-target sputtering process and low efficiency of the existing Ti-Ta alloy thin film, and provides a method for efficiently preparing the Ti-Ta-based high-temperature memory alloy thin film.

A method for efficiently preparing Ti-Ta high-temperature memory alloy thin films is completed in the following steps:

1. First, the Ti target is subjected to fan-shaped hollowing treatment to obtain the Ti target after the hollowing treatment, and then the Ta target is placed at the bottom of the Ti target after the hollowing treatment to obtain a composite target; the atomic fraction of Ti in the composite target is 70% to 90%;

2. Put the composite target into the target position of the single-chamber magnetron sputtering apparatus, fix the substrate on the sample holder, and place the substrate and the composite target opposite to each other, the distance between the substrate and the composite target 60mm ~ 80mm;

3. Vacuuming, when the vacuum degree of the vacuum chamber reaches 1.5×10 ^-4 ~ 3×10 ^-5 Pa, argon gas is introduced until the pressure is 0.1Pa ~ 0.15Pa;

4. Use DC magnetron sputtering, adjust the sputtering power to 100W-200W, and use the composite target as the cathode to deposit for 0.5h-2h to obtain a Ti-Ta high-temperature memory alloy film.

The beneficial effects of the present invention are: the Ti-Ta high-temperature memory alloy film prepared by the method of DC magnetron sputtering in the present invention has a phase transition temperature of over 100°C, can be applied at a relatively high temperature, and has good mechanical properties. performance, and the preparation method is simple and the cost is low. Compared with the traditional single target sputtering, the two steps of vacuum arc melting and rolling alloy target are reduced, and the demand for equipment and procedures are reduced, thereby improving efficiency.

The Ti-Ta alloy thin film can be crystallized without annealing after deposition, and exhibits good mechanical properties. It can be directly peeled off from the SiO ₂ substrate, and a complete alloy thin film can be obtained; NaCl single wafer or KBr single wafer will be used as the substrate The thin film deposited at the bottom is placed in water, and the NaCl single wafer or KBr single wafer is soluble in water, and a complete Ti-Ta alloy thin film can also be obtained.

The preparation method of the Ti-Ta high-temperature memory alloy thin film of the present invention can regulate the phase transition temperature of the thin film by adjusting the content of Ta. The phase transition temperature of the Ti-Ta alloy thin film increases with the reduction of the Ta content, and the phase transition temperature is high. It can be used at 100°C, and the film has good plasticity, which can meet the needs of high temperature applications. By replacing the Ti-Ta alloy target with a composite single target, it avoids the problem that the Ti-Ta alloy is difficult to melt, and one target can only be used to prepare an alloy film with one composition. This method only needs to be changed and the price is relatively low. The size of the hollow sector in the Ti metal target can change the composition of the film, and the crystallized film can be obtained without annealing after deposition, which greatly improves the preparation efficiency and reduces the cost, and has a good application prospect in micro-electromechanical systems. .

Description of drawings

Fig. 1 is the typical cross-sectional SEM morphology figure of the Ti-Ta high temperature memory alloy thin film in embodiment one;

Fig. 2 is a typical surface SEM topography figure of Ti-Ta high temperature memory alloy thin film in embodiment one;

Fig. 3 is the tensile stress-strain curve of the Ti-Ta high temperature memory alloy film at room temperature in Example 1.

Detailed ways

The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

Specific embodiment 1: A method for efficiently preparing Ti-Ta high-temperature memory alloy thin films described in this embodiment is completed according to the following steps:

1. First, the Ti target is subjected to fan-shaped hollowing treatment to obtain the Ti target after the hollowing treatment, and then the Ta target is placed at the bottom of the Ti target after the hollowing treatment to obtain a composite target; the atomic fraction of Ti in the composite target is 70% to 90%;

2. Put the composite target into the target position of the single-chamber magnetron sputtering apparatus, fix the substrate on the sample holder, and place the substrate and the composite target opposite to each other, the distance between the substrate and the composite target 60mm ~ 80mm;

3. Vacuuming, when the vacuum degree of the vacuum chamber reaches 1.5×10 ^-4 ~ 3×10 ^-5 Pa, argon gas is introduced until the pressure is 0.1Pa ~ 0.15Pa;

4. Use DC magnetron sputtering, adjust the sputtering power to 100W-200W, and use the composite target as the cathode to deposit for 0.5h-2h to obtain a Ti-Ta high-temperature memory alloy film.

The beneficial effects of this embodiment are: the Ti-Ta high-temperature memory alloy thin film prepared by the method of DC magnetron sputtering in this embodiment has a phase transition temperature of over 100°C and can be applied at a relatively high temperature with good Compared with the traditional single target sputtering, the two steps of vacuum arc melting and rolling alloy target are reduced, and the demand for equipment and procedures are reduced. Thereby improving efficiency.

The Ti-Ta alloy thin film can be crystallized without annealing after deposition, and exhibits good mechanical properties. It can be directly peeled off from the SiO ₂ substrate, and a complete alloy thin film can be obtained; NaCl single wafer or KBr single wafer will be used as the substrate The thin film deposited at the bottom is placed in water, and the NaCl single wafer or KBr single wafer is soluble in water, and a complete Ti-Ta alloy thin film can also be obtained.

The preparation method of the Ti-Ta high-temperature memory alloy thin film of the present embodiment can adjust the phase transition temperature of the thin film by adjusting the content of Ta. The phase transition temperature of the Ti-Ta alloy thin film increases with the reduction of the Ta content, and the phase transition temperature The temperature is higher than 100°C, and the film has good plasticity, which can meet the needs of high temperature applications. By replacing the Ti-Ta alloy target with a composite single target, it avoids the problem that the Ti-Ta alloy is difficult to melt, and one target can only be used to prepare an alloy film with one composition. This method only needs to be changed and the price is relatively low. The size of the hollow sector in the Ti metal target can change the composition of the film, and the crystallized film can be obtained without annealing after deposition, which greatly improves the preparation efficiency and reduces the cost, and has a good application prospect in micro-electromechanical systems. .

Embodiment 2: The difference between this embodiment and Embodiment 1 is that the thickness of the Ti target described in Step 1 is 2 mm. Others are the same as in the first embodiment.

Specific embodiment three: the difference between this embodiment and specific embodiment one or two is that there are multiple fan-shaped hollows on the Ti target after the hollowing process described in step 1; the fan-shaped hollows take the Ti target circle center as the fan-shaped circle center , the fan-shaped hollows are equiangular fans with an angle of 5° to 10°, and the fan-shaped intervals of multiple fan-shaped hollows are at the same angle. Others are the same as in the first or second embodiment.

Embodiment 4: This embodiment differs from Embodiment 1 to Embodiment 3 in that the substrate described in step 2 is a SiO ₂ single wafer, NaCl single wafer or KBr single wafer. Others are the same as those in Embodiments 1 to 3.

The SiO ₂ single wafer described in this embodiment mode is a (100) single-side polished single wafer.

Embodiment 5: This embodiment differs from Embodiment 1 to Embodiment 4 in that: the SiO _single wafer is ultrasonically cleaned in acetone for 20 min to 30 min, then ultrasonically cleaned in ethanol for 20 min to 30 min, and finally deionized Ultrasonic cleaning in water for 20min to 30min. Others are the same as the specific embodiments 1 to 4.

Embodiment 6: The difference between this embodiment and one of Embodiments 1 to 5 is that in step 3, the vacuum is pumped, and when the vacuum degree of the vacuum chamber reaches 1.5×10 ^-4 Pa, argon gas is introduced until the pressure is 0.13 Pa. . Others are the same as those in Embodiments 1 to 5.

Embodiment 7: This embodiment differs from Embodiments 1 to 6 in that: in step 4, DC magnetron sputtering is used, and the sputtering power is adjusted to 150W, and the composite target is used as the cathode for deposition for 2 hours. Others are the same as those in Embodiments 1 to 6.

Adopt the following examples to verify the beneficial effects of the present invention:

Embodiment one:

A method for efficiently preparing a Ti-Ta-based high-temperature memory alloy thin film described in this embodiment is specifically carried out according to the following steps:

The Ti content in the Ti-Ta alloy film is designed to be 78 atomic percent;

1. First, the Ti target is subjected to fan-shaped hollowing treatment to obtain the Ti target after the hollowing treatment, and then the Ta target is placed at the bottom of the Ti target after the hollowing treatment to obtain a composite target; the atomic fraction of Ti in the composite target is 78%;

2. Put the composite target into the target position of the single-chamber magnetron sputtering apparatus, fix the substrate on the sample holder, and place the substrate and the composite target opposite to each other, the distance between the substrate and the composite target 70mm;

3. Vacuumize. When the vacuum degree of the vacuum chamber reaches 1.5×10 ^-4 Pa, argon gas is introduced until the pressure is 0.13Pa;

4. Use DC magnetron sputtering, adjust the sputtering power to 150W, and use the composite target as the cathode to deposit for 2 hours to obtain a Ti-Ta high-temperature memory alloy film.

The thickness of the Ti target is 2mm.

There are 8 fan-shaped hollows on the Ti target after the hollowing process; the fan-shaped hollows are based on the Ti target circle center as the fan-shaped circle center, and the fan-shaped hollows are equiangular fans with an angle of 10°, and the fan-shaped interval angles of the 8 fan-shaped hollows are the same.

The SiO ₂ single wafer needs to be ultrasonically cleaned in acetone for 20 minutes, then ultrasonically cleaned in ethanol for 20 minutes, and finally deionized water for 20 minutes.

Figure 1 is a typical cross-sectional SEM topography of the Ti-Ta high temperature memory alloy film in Example 1; as can be seen from Figure 1, the film is well bonded to the _SiO2 single wafer substrate, and the interface is clear. Obvious columnar morphology was observed on the film section, and the columnar structure extended from the substrate surface to the film surface, which indicated a typical columnar growth mode during the film growth process.

Fig. 2 is the typical surface SEM topography figure of Ti-Ta high temperature memory alloy thin film in embodiment one; As can be seen from Fig. 2, the surface topography of the thin film after depositing, particle size is relatively uniform, and film-forming quality is good, shows smooth, compact, without Visible holes exist.

Fig. 3 is the tensile stress-strain curve of the Ti-Ta high temperature memory alloy film at room temperature in Example 1. As can be seen from the figure, the prepared film utilizes the tensile method to measure the shape memory effect, and the sample is fully recoverable after heating. The strain is 1.7 %.

Table 1: Composition of the Ti-Ta-based high-temperature memory alloy film in Example 1

element mass percentage atomic weight percent Ta M 51.14 21.69 TiK 48.86 78.31

Table 1 shows the composition of the Ti-Ta high temperature memory alloy thin film in Example 1. It can be seen from Table 1 that the Ti atomic percentage of the thin film obtained in this embodiment is 78.31 at%, and the Ta atomic percentage is 21.69%.

Embodiment two:

A kind of method for efficiently preparing Ti-Ta high-temperature memory alloy film described in this embodiment is specifically carried out according to the following steps:

The Ti content in the Ti-Ta alloy film is designed to be 90 atomic percent;

1. First, the Ti target is subjected to fan-shaped hollowing treatment to obtain the Ti target after the hollowing treatment, and then the Ta target is placed at the bottom of the Ti target after the hollowing treatment to obtain a composite target; the atomic fraction of Ti in the composite target is 90%;

2. Put the composite target into the target position of the single-chamber magnetron sputtering apparatus, fix the substrate on the sample holder, and place the substrate and the composite target opposite to each other, the distance between the substrate and the composite target 70mm;

3. Vacuumize. When the vacuum degree of the vacuum chamber reaches 1.5×10 ^-4 Pa, argon gas is introduced until the pressure is 0.13Pa;

4. Use DC magnetron sputtering, adjust the sputtering power to 150W, and use the composite target as the cathode to deposit for 2 hours to obtain a Ti-Ta high-temperature memory alloy film.

The thickness of the Ti target is 2mm.

There are 6 fan-shaped hollows on the Ti target after the hollowing process; the fan-shaped hollows are based on the Ti target circle center as the fan-shaped circle center, and the fan-shaped hollows are equiangular fans with an angle of 10°, and the fan-shaped interval angles of the 6 fan-shaped hollows are the same.

The SiO ₂ single wafer needs to be ultrasonically cleaned in acetone for 20 minutes, then ultrasonically cleaned in ethanol for 20 minutes, and finally deionized water for 20 minutes.

The Ti—Ta alloy thin film obtained in this embodiment has an atomic percentage of Ti of 90%, and an atomic percentage of Ta of 10%.

Embodiment three:

A kind of method for efficiently preparing Ti-Ta high-temperature memory alloy film described in this embodiment is specifically carried out according to the following steps:

The Ti content in the Ti-Ta alloy film is designed to be 70 atomic percent;

1. First, the Ti target is subjected to fan-shaped hollowing treatment to obtain the Ti target after the hollowing treatment, and then the Ta target is placed at the bottom of the Ti target after the hollowing treatment to obtain a composite target; the atomic fraction of Ti in the composite target is 70%;

2. Put the composite target into the target position of the single-chamber magnetron sputtering apparatus, fix the substrate on the sample holder, and place the substrate and the composite target opposite to each other, the distance between the substrate and the composite target 70mm;

3. Vacuumize. When the vacuum degree of the vacuum chamber reaches 1.5×10 ^-4 Pa, argon gas is introduced until the pressure is 0.13Pa;

4. Use DC magnetron sputtering, adjust the sputtering power to 150W, and use the composite target as the cathode to deposit for 2 hours to obtain a Ti-Ta high-temperature memory alloy film.

The thickness of the Ti target is 2mm.

There are 9 fan-shaped hollows on the Ti target after the hollowing process; the fan-shaped hollows are based on the Ti target circle center as the fan-shaped circle center, and the fan-shaped hollows are equiangular fans with an angle of 10°, and the fan-shaped interval angles of the 9 fan-shaped hollows are the same.

The SiO ₂ single wafer needs to be ultrasonically cleaned in acetone for 20 minutes, then ultrasonically cleaned in ethanol for 20 minutes, and finally deionized water for 20 minutes.

The Ti—Ta alloy thin film obtained in this embodiment has an atomic percentage of Ti of 70% and an atomic percentage of Ta of 30%.

Claims (7)

1. efficiently prepare a method for Ti-Ta high temperature shape memory alloy film, it is characterized in that a kind of method of the efficient Ti-Ta of preparation high temperature shape memory alloy film completes according to the following steps:

One, first fan-shaped hollow out process is carried out to Ti target, obtain the Ti target after hollow out process, then Ta target is placed in bottom the Ti target after hollow out process, obtain composite target material; In described composite target material, the atomic fraction of Ti is 70% ~ 90%;

Two, loaded by composite target material on the target position of single chamber magnetic control sputtering device, be fixed on sample carrier by substrate, and substrate and composite target material are put in opposite directions, the distance between substrate and composite target material is 60mm ~ 80mm;

Three, vacuumize, when the vacuum tightness of vacuum chamber reaches 1.5 × 10 ^-4~ 3 × 10 ^-5after Pa, passing into argon gas to pressure is 0.1Pa ~ 0.15Pa;

Four, utilize magnetically controlled DC sputtering, and regulate sputtering power to be 100W ~ 200W, carry out deposition 0.5h ~ 2h using composite target material as negative electrode, namely obtain Ti-Ta high temperature shape memory alloy film.

2. a kind of efficient method preparing Ti-Ta high temperature shape memory alloy film according to claim 1, is characterized in that the Ti target thickness described in step one is 2mm.

3. a kind of efficient method preparing Ti-Ta high temperature shape memory alloy film according to claim 1, is characterized in that the Ti target after the hollow out process described in step one has multiple fan-shaped hollow out; Fan-shaped hollow out is the fan-shaped center of circle with the Ti target center of circle, fan-shaped hollow out to be angle be 5 ° ~ 10 ° angularly fan-shaped, and the fan-shaped interval angles of multiple fan-shaped hollow out is identical.

4. a kind of efficient method preparing Ti-Ta high temperature shape memory alloy film according to claim 1, is characterized in that the substrate described in step 2 is SiO ₂single-chip, NaCl single-chip or KBr single-chip.

5. a kind of efficient method preparing Ti-Ta high temperature shape memory alloy film according to claim 4, is characterized in that described SiO ₂single-chip ultrasonic cleaning 20min in acetone ~ 30min, then ultrasonic cleaning 20min ~ 30min in ethanol, finally deionized water for ultrasonic ripple cleaning 20min ~ 30min again.

6. a kind of efficient method preparing Ti-Ta high temperature shape memory alloy film according to claim 1, is characterized in that vacuumizing in step 3, when the vacuum tightness of vacuum chamber reaches 1.5 × 10 ^-4after Pa, passing into argon gas to pressure is 0.13Pa.

7. a kind of efficient method preparing Ti-Ta high temperature shape memory alloy film according to claim 1, is characterized in that utilizing magnetically controlled DC sputtering in step 4, and regulates sputtering power to be 150W, carries out deposition 2h using composite target material as negative electrode.