阅读说明：本技术 一种3C-SiC薄膜的制备方法 (Preparation method of 3C-SiC film ) 是由 范梦慧 谢泉 艾学正 王凯 杨云飞 李鑫 于 2020-06-08 设计创作，主要内容包括：本发明涉及一种3C-SiC薄膜的制备方法,属于半导体材料技术领域。上述制备方法包括如下步骤：S1.选取石墨作为衬底；S2.选取金属催化剂和靶材,其中,金属催化剂为铜、银和金中的任意一种；所述靶材为Si靶；S3.使用金属催化剂和靶材在石墨上溅射沉积形成含有金属催化剂的Si膜；其中,金属催化剂的表面积与靶材的表面积比为0.02-0.20；S4.将步骤S3得到的含有金属催化剂的Si膜进行真空热处理,即得到3C-SiC薄膜。本发明工艺操作更为简便,形成的3C-SiC薄膜结晶度高,在高温热处理下几乎未有薄膜皲裂发生,具有较好的质量。(The invention relates to a preparation method of a 3C-SiC film, belonging to the technical field of semiconductor materials. The preparation method comprises the following steps: s1, selecting graphite as a substrate; s2, selecting a metal catalyst and a target material, wherein the metal catalyst is any one of copper, silver and gold; the target material is a Si target; s3, sputtering and depositing on graphite by using a metal catalyst and a target to form a Si film containing the metal catalyst; wherein the ratio of the surface area of the metal catalyst to the surface area of the target material is 0.02-0.20; and S4, carrying out vacuum heat treatment on the Si film containing the metal catalyst obtained in the step S3 to obtain the 3C-SiC film. The invention has simpler and more convenient process operation, and the formed 3C-SiC film has high crystallinity, almost no film chapping under high-temperature heat treatment and better quality.)

1. A preparation method of a 3C-SiC film is characterized by comprising the following steps:

s1, selecting graphite as a substrate;

s2, selecting a metal catalyst and a target material, wherein the metal catalyst is any one of copper, silver and gold; the target material is a Si target;

s3, sputtering and depositing on the graphite in the step S1 by using the metal catalyst in the step S2 and the target in the step S2 to form a Si film containing the metal catalyst;

wherein the ratio of the surface area of the metal catalyst to the surface area of the target material is 0.02-0.20;

and S4, carrying out vacuum heat treatment on the Si film containing the metal catalyst on the graphite substrate obtained in the step S3 to obtain the 3C-SiC film.

2. The method for producing a 3C-SiC film according to claim 1, wherein in step S1, the graphite is obtained by: polishing one side of the graphite sheet, and sequentially cleaning with acetone and absolute alcohol, deionized water and blow-drying to obtain the ink.

3. The method for producing a 3C-SiC film according to claim 2, wherein the graphite sheet is a high-purity graphite sheet.

4. The method for preparing a 3C-SiC film according to claim 1, wherein the step S2 further comprises a step of pretreating the metal catalyst, specifically as follows: and carrying out primary ultrasonic cleaning on the metal catalyst by using acetone and absolute ethyl alcohol, carrying out secondary ultrasonic cleaning on the metal catalyst subjected to the primary ultrasonic cleaning by using deionized water, and blow-drying to obtain the pretreated metal catalyst.

5. The method for producing a 3C-SiC film according to claim 1, wherein in step S3, the conditions of the sputter deposition are: vacuum degree less than or equal to 8.0 multiplied by 10^-5Pa, the sputtering pressure is 1.0Pa to 4.0Pa, the argon flow is 10sccm to 25sccm, and the sputtering power is 80W to 140W.

6. The method of producing a 3C-SiC thin film according to claim 1, wherein in step S3, the thickness of the Si film is 220nm to 840 nm.

7. The method of claim 1, wherein in step S3, the metal catalyst of step S2 and the target of step S2 are subjected to sputtering for 10min to 15min before the sputtering deposition.

8. The method for producing a 3C-SiC film according to claim 7, wherein the conditions of the sputtering treatment are: vacuum degree less than or equal to 8.0 multiplied by 10^-5Pa, the sputtering pressure is 1.0Pa to 4.0Pa, the argon flow is 10sccm to 25sccm, and the sputtering power is 80W to 140W.

9. The method for producing a 3C-SiC film according to claim 1, wherein in step S4, the specific method of the vacuum heat treatment is: under the vacuum degree of less than or equal to 8.0 multiplied by 10^-4And under the condition of Pa, heating the Si film containing the metal catalyst obtained in the step S3 to 950-1080 ℃, and naturally cooling after keeping the temperature for 1-14 h.

10. The method for preparing 3C-SiC film according to claim 9, wherein the degree of vacuum of natural cooling is not more than 2.0X 10^-3Pa。

Technical Field

The invention belongs to the technical field of semiconductor materials, and particularly relates to a preparation method of a 3C-SiC film.

Background

The 3C-SiC is cubic phase silicon carbide, has the performances of high heat conductivity, high electronic saturation velocity, high breakdown voltage, low dielectric constant and the like, and has great potential in the fields of preparing high temperature resistant, high power, high frequency and strong radiation resistant semiconductor optoelectronic devices and the like. 3C-SiC is a new generation of wide bandgap semiconductor material that can be used under extreme conditions.

Currently, there are two main methods for preparing SiC thin films: chemical vapor deposition and physical vapor deposition. The chemical vapor deposition method is a method in which two or more gaseous raw materials are introduced into a reaction chamber to undergo a chemical reaction to form a new material, and the new material is deposited on a substrate to form a thin film having a stable structure, but the chemical vapor deposition method is used as a gas source for thin film growth (e.g., SiH)₄、C₃H₈Etc.) are mostly inflammable, explosive, toxic and harmful substances which are not good for human health, and the gas source has low utilization rate and high cost.

In the RF magnetron sputtering of physical vapor deposition, inert gas such as argon (Ar) gas is filled to low pressure under the vacuum condition, and argon (Ar) atoms are ionized into argon ions (Ar) under the action of RF alternating current electric field applied between the target material and the substrate⁺) The target material is accelerated and bombarded by argon ions under the action of an electric field force, the target material is sputtered and deposited on the surface of the substrate, the process is simple, the environment is better, the substrate used by the SiC film prepared by magnetron sputtering generally takes a high-purity monocrystalline silicon wafer, a glass sheet, sapphire or steel base as the substrate, the cost is higher, the large lattice mismatch exists between the SiC and the substrate, the heat treatment temperature is high, and the generated SiC film is easy to chap. Therefore, a preparation method of the 3C-SiC film which can achieve both production efficiency and production quality is needed in the market.

Disclosure of Invention

The invention provides a preparation method of a 3C-SiC film, which aims to solve the technical problems in the background technology and can solve the problem that the production efficiency and the production quality are difficult to be considered simultaneously in the conventional preparation method for producing the 3C-SiC film.

The technical scheme for solving the technical problems is as follows: a preparation method of a 3C-SiC film comprises the following steps:

s1, selecting graphite as a substrate;

s2, selecting a metal catalyst and a target material, wherein the metal catalyst is any one of copper, silver and gold; the target material is a Si target;

s3, sputtering and depositing on the graphite in the step S1 by using the metal catalyst in the step S2 and the target in the step S2 to form a Si film layer containing the metal catalyst;

wherein the ratio of the surface area of the metal catalyst to the surface area of the target material is 0.02-0.3;

and S4, carrying out vacuum heat treatment on the Si film containing the metal catalyst obtained in the step S3 to obtain the 3C-SiC film.

The invention has the beneficial effects that:

(1) according to the invention, the metal catalyst and the target material are sputtered and deposited together on the graphite substrate, so that the crystal nucleus recrystallization in the 3C-SiC generation process can be accelerated in the heat treatment process, the crystallinity is obviously improved, and meanwhile, the film is hardly cracked under the high-temperature heat treatment, so that the graphite substrate has good quality;

(2) the sputtering deposition process is simpler and more convenient to operate, the number of the metal foils of the catalyst can be effectively controlled, and the atomic percentage of the target material and the metal catalyst can be effectively controlled, so that the quality of the 3C-SiC film is improved;

(3) the invention takes graphite as a substrate, the graphite has rich sources and low price, and has no pollution to the environment, and the cost can be effectively controlled;

(4) the graphite has the advantages of small density, small thermal expansion coefficient, high chemical stability, high melting point, high thermal conductivity and the like, and particularly, the thermal expansion coefficient between the graphite and the SiC is very close in a high-temperature environment, so that the performance of the 3C-SiC film can be improved;

(5) the graphite belongs to a layered structure, so that the 3C-SiC film on the graphite is easy to mechanically peel off, and the 3C-SiC film prepared on the graphite substrate can be transferred to other substrates or devices;

(6) the invention can control the content of the metal catalyst of the 3C-SiC film by limiting the surface area ratio of the metal catalyst to the surface area ratio of the target material, and has convenient operation.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, in step S1, the graphite is obtained by the following method: polishing one side of the graphite sheet, and sequentially cleaning with acetone and absolute alcohol, deionized water and blow-drying to obtain the ink.

The beneficial effect of adopting the further scheme is that: the organic matter on the surface of the graphite can be removed by pretreating the graphite.

Further, the graphite flake is a high-purity graphite flake.

It is to be understood that the high purity graphite flake is processed from a high purity graphite material having a density greater than 1.8g/cm³The compression strength is more than 65MPa, the breaking strength is more than 35MPa, the specific resistance is less than 10, and the ash content is less than 0.05.

Further, step S2 further includes a step of pretreating the metal catalyst, specifically as follows: and carrying out primary ultrasonic cleaning on the metal catalyst by using acetone and absolute ethyl alcohol, carrying out secondary ultrasonic cleaning on the metal catalyst subjected to the primary ultrasonic cleaning by using deionized water, and blow-drying to obtain the pretreated metal catalyst.

The beneficial effect of adopting the further scheme is that: the organic matter on the surface of the metal catalyst can be removed by pretreating the metal catalyst, and the deposited 3C-SiC film is ensured not to contain impurities.

Further, in step S3, the conditions of the sputter deposition are: vacuum degree less than or equal to 8.0 multiplied by 10^-5Pa, the sputtering pressure is 1.0Pa to 4.0Pa, the argon flow is 10sccm to 25sccm, and the sputtering power is 80W to 140W.

The beneficial effect of adopting the further scheme is that: the invention adopts a magnetron co-sputtering method, has easily controlled technological parameters and is beneficial to promoting the large-scale production of the 3C-SiC film.

Further, in step S3, the Si film thickness is 220nm to 840 nm.

The beneficial effect of adopting the further scheme is that: by controlling the thickness of the film, the film stress can be effectively improved, and the film surface can be further prevented from cracking.

Further, in step S3, before the sputter deposition, the metal catalyst of step S2 and the target of step S2 are subjected to a sputtering process for 10min to 15 min.

The beneficial effect of adopting the further scheme is that: before the sputtering deposition, the metal catalyst and the target material are sputtered, so that the oxide layers on the metal catalyst and the target material can be removed.

Further, the conditions of the sputtering treatment are as follows: vacuum degree less than or equal to 8.0 multiplied by 10^-5Pa, the sputtering pressure is 1.0Pa to 4.0Pa, the argon flow is 10sccm to 25sccm, and the sputtering power is 80W to 140W.

Further, in step S4, the specific method of the vacuum heat treatment is: under the vacuum degree of less than or equal to 8.0 multiplied by 10^-4And under the condition of Pa, heating the Si film containing the metal catalyst obtained in the step S3 to 950-1080 ℃, and naturally cooling after keeping the temperature for 1-14 h.

The beneficial effect of adopting the further scheme is that: the metal catalyst has good wettability at high temperature, has high solubility to Si and C, can improve the mutual diffusion rate of Si atoms and C atoms, and can accelerate the recrystallization of 3C-SiC crystal nucleus.

Furthermore, the vacuum degree of the natural cooling is less than or equal to 2.0 multiplied by 10^-3Pa。

The beneficial effect of adopting the further scheme is that: the formation of the 3C-SiC film is facilitated by improving the vacuum degree of natural cooling.

Drawings

FIG. 1 is an X-ray diffraction pattern of a sample prepared by depositing a 560nm thick Si film on a high purity graphite sheet according to the present invention, with copper atom contents of different percentages, at a temperature of 1080 ℃ and a holding time of 12 hours;

FIG. 2 is a scanning electron microscope image of a sample prepared according to the present invention by depositing a 560nm thick Si film on a high purity graphite sheet, without copper, at 1080 ℃ and 12 hours holding time;

FIG. 3 is a scanning electron microscope image of a sample prepared according to the present invention by depositing a 560nm thick Si film on a high purity graphite flake at 0.06 at.% copper at 1080 ℃ for 12 hours;

FIG. 4 is a scanning electron microscope image of a sample prepared according to the present invention by depositing a 560nm thick Si film on a high purity graphite flake at 0.10 at.% copper at 1080 ℃ for 12 hours;

FIG. 5 is a scanning electron microscope image of a sample prepared according to the present invention by depositing a 560nm thick Si film on a high purity graphite flake at 0.15 at.% copper at 1080 ℃ for 12 hours;

FIG. 6 is a scanning electron microscope image of a sample prepared according to the present invention by depositing a 560nm thick Si film on a high purity graphite flake at 0.36 at.% copper at 1080 ℃ for 12 hours;

FIG. 7 shows that the Raman peak of a sample prepared by depositing a 560nm thick Si film on a high-purity graphite sheet according to the present invention, wherein the copper atom content is different percentages, the temperature is 1080 ℃, and the holding time is 12 hours, is 400cm^-1-1800cm^-1Raman spectrogram of (1);

FIG. 8 shows that the Raman peak of a sample prepared by depositing a 560nm thick Si film on a high-purity graphite sheet according to the present invention at different atomic percentages of copper and 1080 ℃ for 12 hours is 650cm^-1-1000cm^-1Raman spectrum of (a).

Detailed Description

The technical solution of the present invention will be described in more detail with reference to the following embodiments, wherein the raw materials such as graphite, metal catalyst and target material can be purchased commercially, for example, graphite can be purchased from high purity graphite flake (specification: 15mmx15mmx1mm) of carbon ltd; the copper foil may be obtained from copper foil available from Wanjia copper industries, Inc., Shandong (specification: 5mmx5mmx1 mm); the Si target can be obtained from Si targets (purity: 99.99%, specification: diameter: 60mm, thickness: 5mm) of Izod, Seikagaku, Technique, Ltd.