Gallium oxide thin film based on low-oxygen-content gallium oxide buffer layer and preparation method of gallium oxide thin film

Abstract

The invention provides a gallium oxide thin film based on a low-oxygen-content gallium oxide buffer layer and a preparation method of the gallium oxide thin film, and relates to the technical field of semiconductor material manufacturing processes. The preparation method of the gallium oxide thin film comprises the following steps: performing magnetron sputtering on the surface of a substrate by adopting gallium oxide as a target material in a rare gas atmosphere to obtain the substrate with a low-oxygen-content gallium oxide buffer layer; performing magnetron sputtering on the surface of the low-oxygen-content gallium oxide buffer layer of the substrate with the low-oxygen-content gallium oxide buffer layer by adopting gallium oxide as a target material in a mixed atmosphere of oxygen and rare gas to obtain a gallium oxide thin film; and annealing the gallium oxide thin film to obtain the gallium oxide thin film based on the low-oxygen-content gallium oxide buffer layer. According to the invention, the gallium oxide buffer layer with low oxygen content is prepared on the substrate and then the gallium oxide thin film is prepared, so that the influence of thermal mismatch and lattice mismatch on the crystallization performance of the gallium oxide thin film in the high-temperature annealing process is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor material manufacturing process, and in particular to a gallium oxide film based on a low-oxygen-content gallium oxide buffer layer and a preparation method thereof. Background Art

[0002] Gallium oxide is a wide bandgap semiconductor with a bandgap of 4.5 to 4.9 eV. Due to its wide bandgap, it has a transmittance of more than 80% in the visible light band, and it has strong light absorption characteristics in the deep ultraviolet band, especially at 250nm of its absorption edge. It also has the advantages of large breakdown electric field, high stability, and small dielectric constant, and has shown great application potential in 5G communications, ultraviolet detection, solar cells, new energy vehicles and other fields.

[0003] Gallium oxide thin films can be well applied to devices due to their two-dimensional characteristics, and the film quality of gallium oxide thin films greatly affects the performance of gallium oxide thin film devices. At present, the methods for growing gallium oxide thin films are mainly divided into homoepitaxial growth and heteroepitaxial growth. Although homoepitaxial growth does not have problems such as lattice mismatch and can obtain high-quality thin films, it is difficult and costly to prepare large-sized single-crystal gallium oxide, and gallium oxide is difficult to form a P-type doped semiconductor due to its own physical properties. In summary, all of these will affect the practical application of homoepitaxially grown gallium oxide thin films. Heteroepitaxial growth is mainly on silicon, quartz, and sapphire substrates. Compared with sapphire, silicon substrates have excellent thermal conductivity, and large-sized silicon substrates have a relatively mature process, low cost, and are conducive to the integration of gallium oxide-based devices and silicon-based devices. Quartz has advantages as a substrate for photodetectors because of its high transparency in visible light and ultraviolet light. However, there is a large lattice mismatch and thermal mismatch between silicon or quartz and gallium oxide, and it is easy to produce interfacial stacking faults during the preparation of gallium oxide thin films. Patent publication number CN107785241B discloses a method for preparing a β-gallium oxide film on a silicon substrate, and growing a β-gallium oxide nanocolumn array on the silicon substrate as a buffer layer. However, this method has cumbersome operating steps, involves multiple chemical reactions and high-temperature annealing, is environmentally unfriendly, and is highly dangerous. At present, the quality of the gallium oxide film prepared on the Si substrate is poor. Not only can it not form β-Ga2O3 with good crystallinity, but sometimes even the problem of film cracking during high-temperature annealing may occur. In addition, the prior art discloses a technical solution for preparing a gallium oxide film using aluminum nitride as a buffer layer, but this solution also has the problem of low thermal expansion coefficient and lattice adaptability, which can easily cause the film to crack during the annealing process, and during the annealing process, it will also cause Al and N elements to be doped into the gallium oxide film, affecting its properties.

[0004] In summary, those skilled in the art are in urgent need of developing a gallium oxide thin film based on a low-oxygen gallium oxide buffer layer and a preparation method thereof to solve the problems of high cost, low efficiency, complex method, and lattice mismatch or thermal mismatch between the substrate and the thin film in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a gallium oxide film based on a low-oxygen content gallium oxide buffer layer and a preparation method thereof, so as to solve the problems of high cost, low efficiency, complex method and lattice mismatch or thermal mismatch between the substrate and the film in the prior art.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a gallium oxide film based on a low-oxygen-content gallium oxide buffer layer, comprising the following steps:

[0008] 1) Under an argon atmosphere, magnetron sputtering is performed on the surface of a substrate using gallium oxide as a target material to obtain a substrate with a low-oxygen-content gallium oxide buffer layer;

[0009] 2) in a mixed atmosphere of oxygen and argon, magnetron sputtering is performed on the surface of the low-oxygen-content gallium oxide buffer layer of the substrate with the low-oxygen-content gallium oxide buffer layer using gallium oxide as a target material to obtain a gallium oxide film;

[0010] 3) Annealing the gallium oxide film prepared in step 2) to obtain a gallium oxide film based on a low-oxygen-content gallium oxide buffer layer.

[0011] Preferably, the parameters of the magnetron sputtering in step 1) are as follows:

[0012] The power of the radio frequency power supply is 20 to 120 W, the flow rate of the rare gas is 20 to 50 sccm, the working gas pressure is 5 to 15 mTorr, and the rotation rate of the substrate is 10 to 30 rad / min.

[0013] Preferably, the substrate in step 1) is a Si substrate or a SiO2 substrate.

[0014] Preferably, the low oxygen content gallium oxide buffer layer in step 1) has a thickness of 10 to 400 nm.

[0015] Preferably, the parameters of the magnetron sputtering in step 2) are as follows:

[0016] The flow rate of the rare gas is 20 to 50 sccm, the flow rate of the oxygen is 0 to 8 sccm, and the working gas pressure is 5 to 15 mTorr, wherein the flow rate of the oxygen is not 0;

[0017] The power of the radio frequency power supply is 20 to 120 W, and the rotation speed of the substrate is 10 to 30 rad / min.

[0018] Preferably, the gallium oxide film in step 2) has a thickness of 10 to 1000 nm.

[0019] Preferably, the temperature of the annealing treatment in step 3) is 900-1100° C., the heating rate is 0.5-20° C. / min, and the holding time is 0.5-4 h.

[0020] Preferably, the atmosphere of the annealing treatment in step 3) includes one or more of air, oxygen, nitrogen and argon.

[0021] The present invention also provides a gallium oxide film based on a low-oxygen-content gallium oxide buffer layer prepared by the above preparation method.

[0022] The present invention has at least the following beneficial effects:

[0023] A buffer layer film and a gallium oxide film of suitable thickness are prepared by a single magnetron sputtering method, and the effect of thermal mismatch and lattice mismatch on the crystallization properties of the gallium oxide film during high-temperature annealing is reduced by growing the buffer layer film, thereby obtaining a higher quality gallium oxide film. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flow chart of the preparation of a gallium oxide thin film based on a low oxygen content gallium oxide buffer layer;

[0025] Figure 2 X-ray diffraction (XRD) patterns of the gallium oxide thin films prepared in Example 1 and Comparative Example 1 before annealing and after annealing at different temperatures;

[0026] Figure 3 is a comparison diagram of the full width at half maximum (FWHM) of different crystalline phases of the gallium oxide thin film prepared in Example 1 and Comparative Example 1 after annealing the gallium oxide thin film under different temperature conditions, Figure 3 (a) is a comparison of the half-peak width of the (400) crystal phase. Figure 3 (b) is a comparison diagram of the half-peak width of the (-202) crystal phase;

[0027] Figure 4 The Raman spectra of the gallium oxide films prepared in Example 2 and Comparative Example 2. DETAILED DESCRIPTION

[0028] The present invention provides a method for preparing a gallium oxide film based on a low-oxygen-content gallium oxide buffer layer, comprising the following steps:

[0029] 1) Under an argon atmosphere, magnetron sputtering is performed on the surface of a substrate using gallium oxide as a target material to obtain a substrate with a low-oxygen-content gallium oxide buffer layer;

[0030] 2) in a mixed atmosphere of oxygen and argon, magnetron sputtering is performed on the surface of the low-oxygen-content gallium oxide buffer layer of the substrate with the low-oxygen-content gallium oxide buffer layer using gallium oxide as a target material to obtain a gallium oxide film;

[0031] 3) Annealing the gallium oxide film prepared in step 2) to obtain a gallium oxide film based on a low-oxygen-content gallium oxide buffer layer.

[0032] The process flow chart of the above preparation method is as follows Figure 1 shown.

[0033] In the present invention, the purity of gallium oxide used as a target material is 99.99% or more.

[0034] In the present invention, the parameters of the magnetron sputtering described in step 1) are as follows:

[0035] The power of the RF power supply is 20-120 W, preferably 40-100 W, further preferably 60-80 W, and more preferably 65-75 W; the flow rate of the rare gas is 20-50 sccm, preferably 25-45 sccm, further preferably 30-40 sccm, and more preferably 35 sccm; the working gas pressure is 5-15 mTorr, preferably 7-13 mTorr, further preferably 8-12 mTorr, and more preferably 9-10 mTorr; the rotation rate of the substrate is 10-30 rad / min, preferably 12-28 rad / min, further preferably 15-25 rad / min, and more preferably 18-22 rad / min.

[0036] In the present invention, the substrate in step 1) is a Si substrate or a SiO2 substrate.

[0037] In the present invention, the substrate needs to be surface treated by the following steps before magnetron sputtering: the substrate is soaked and cleaned in a hydrofluoric acid solution, and then ultrasonically cleaned with ultrapure water, ethanol, acetone, and ultrapure water for 5 to 25 minutes, preferably 10 to 20 minutes, and more preferably 15 minutes, and finally dried with nitrogen for use.

[0038] The volume concentration of the hydrofluoric acid solution is 5-15%, preferably 8-12%, and more preferably 10%; the soaking and cleaning time is 5-15 minutes, preferably 8-12 minutes, and more preferably 10 minutes.

[0039] In the present invention, the thickness of the low oxygen content gallium oxide buffer layer in step 1) is 10 to 400 nm, preferably 50 to 350 nm, more preferably 100 to 300 nm, and even more preferably 150 to 250 nm.

[0040] In the present invention, the parameters of the magnetron sputtering in step 2) are as follows:

[0041] The flow rate of the rare gas is 20 to 50 sccm, preferably 25 to 45 sccm, more preferably 30 to 40 sccm, and more preferably 32 to 38 sccm; the flow rate of the oxygen is 0 to 8 sccm, preferably 1 to 7 sccm, more preferably 2 to 6 sccm, and more preferably 3 to 5 sccm; the working gas pressure is 5 to 15 mTorr, preferably 7 to 13 mTorr, more preferably 9 to 11 mTorr, and more preferably 10 mTorr; wherein the flow rate of the oxygen is not 0;

[0042] The power of the RF power supply is 20-120 W, preferably 40-100 W, more preferably 50-90 W, and more preferably 60-80 W; the rotation speed of the substrate is 10-30 rad / min, preferably 13-28 rad / min, more preferably 15-25 rad / min, and more preferably 18-22 rad / min.

[0043] In the present invention, before the magnetron sputtering, the space inside the magnetron sputtering needs to be evacuated to a vacuum degree of 10 -6 Torr and above.

[0044] In the present invention, the gallium oxide film in step 2) has a thickness of 10 to 1000 nm, preferably 50 to 800 nm, more preferably 100 to 600 nm, and even more preferably 200 to 400 nm.

[0045] In the present invention, the temperature of the annealing treatment in step 3) is 900-1100°C, preferably 950-1050°C, more preferably 980-1020°C, and more preferably 1000°C; the heating rate is 0.5-20°C / min, preferably 1-10°C / min, more preferably 2-5°C / min, and more preferably 2°C / min; the holding time is 0.5-4h, preferably 1-3h, and more preferably 2h.

[0046] In the present invention, the atmosphere of the annealing treatment in step 3) includes one or more of air, oxygen, nitrogen and argon.

[0047] The present invention also provides a gallium oxide film based on a low-oxygen-content gallium oxide buffer layer prepared by the above preparation method.

[0048] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0049] Example 1

[0050] (1) Take a 10 mm × 10 mm Si substrate with a lattice orientation of (100). Soak the substrate in a 10% volume fraction hydrofluoric acid solution for 10 minutes, then ultrasonically clean it in ultrapure water, ethanol, acetone, and ultrapure water for 15 minutes respectively. Then blow dry with nitrogen for later use.

[0051] The cleaned Si substrate was placed in a magnetron sputtering chamber (Denton E20 magnetron sputtering instrument), and then the chamber was evacuated to remove oxygen. -6 After 30 min of sputtering at a working pressure of 10 mTorr, 42 sccm of argon was introduced, the sputtering power was set to 80 W, and gallium oxide (purity 99.99%, Beijing Zhongcheng New Materials) was used as the sputtering target to obtain a 50 nm thick low-oxygen gallium oxide film as a buffer layer.

[0052] (2) The Si substrate with the low-oxygen gallium oxide thin film buffer layer is placed in a magnetron sputtering chamber. -6 After 38 sccm of argon and 4 sccm of oxygen were introduced, the sputtering power was set to 50W, gallium oxide was used as the sputtering target, and the sputtering was performed for 180 minutes at a working pressure of 10 mTorr to obtain a 200 nm thick gallium oxide film.

[0053] Repeat steps (1) and (2) to obtain four identical gallium oxide films.

[0054] (3) Three of the four gallium oxide films were annealed at different temperatures in a tube furnace, with a heating rate of 2°C / min. The annealing temperatures were 900°C, 1000°C, and 1100°C, respectively. The annealing atmosphere was air. After annealing, the films were naturally cooled to room temperature to obtain the final sample, which was a gallium oxide film based on a low-oxygen gallium oxide buffer layer.

[0055] Example 2

[0056] (1) Take a 10 mm × 10 mm Si substrate with a lattice orientation of (100). Soak the substrate in a 10% volume fraction hydrofluoric acid solution for 10 minutes, then ultrasonically clean it in ultrapure water, ethanol, acetone, and ultrapure water for 15 minutes respectively. Then blow dry with nitrogen for later use.

[0057] The cleaned Si substrate was placed in the magnetron sputtering chamber, and then the chamber was evacuated to remove oxygen. -6 After 30 min of sputtering at a working pressure of 10 mTorr, 42 sccm of argon was introduced, the sputtering power was set to 120 W, and gallium oxide was used as the sputtering target to obtain a 400 nm thick low-oxygen gallium oxide film as a buffer layer.

[0058] (2) The Si substrate with the low-oxygen gallium oxide thin film buffer layer is placed in a magnetron sputtering chamber. -6 After 38 sccm of argon and 4 sccm of oxygen were introduced, the sputtering power was set to 120W, gallium oxide was used as the sputtering target, and the sputtering was performed for 180 minutes at a working pressure of 10 mTorr to obtain a gallium oxide film with a thickness of 1000 nm.

[0059] (3) placing the gallium oxide film prepared in step (2) in a tubular furnace for annealing at different temperatures, with a heating rate of 2°C / min, an annealing temperature of 1000°C, and an annealing atmosphere of air. After the annealing is completed, the film is naturally cooled to room temperature to obtain a final sample of a gallium oxide film based on a low-oxygen content gallium oxide buffer layer.

[0060] Example 3

[0061] (1) Take a 10 mm × 10 mm amorphous SiO2 substrate. Soak the substrate in a 10% volume fraction hydrofluoric acid solution for 10 minutes, then ultrasonically clean it in ultrapure water, ethanol, acetone, and ultrapure water for 15 minutes respectively. Then blow dry with nitrogen for later use.

[0062] The cleaned SiO2 substrate is placed in the magnetron sputtering chamber, and then the chamber is evacuated to remove oxygen. -6 After 30 min of sputtering at a working pressure of 10 mTorr, 42 sccm of argon was introduced, the sputtering power was set to 80 W, and gallium oxide was used as the sputtering target to obtain a 50 nm thick low-oxygen gallium oxide film as a buffer layer.

[0063] (2) The Si substrate with the low-oxygen gallium oxide thin film buffer layer is placed in a magnetron sputtering chamber. -6 After 38 sccm of argon and 4 sccm of oxygen were introduced, the sputtering power was set to 50W, gallium oxide was used as the sputtering target, and the sputtering was performed for 180 minutes at a working pressure of 10 mTorr to obtain a 200 nm thick gallium oxide film.

[0064] (3) placing the gallium oxide film prepared in step (2) in a tubular furnace for annealing at different temperatures, with a heating rate of 2°C / min, an annealing temperature of 1000°C, and an annealing atmosphere of air. After the annealing is completed, the film is naturally cooled to room temperature to obtain a final sample of a gallium oxide film based on a low-oxygen content gallium oxide buffer layer.

[0065] Comparative Example 1

[0066] (1) Take a 10 mm × 10 mm Si substrate with a lattice orientation of (100). Soak the substrate in a 10% volume fraction hydrofluoric acid solution for 10 minutes, then ultrasonically clean it in ultrapure water, ethanol, acetone, and ultrapure water for 15 minutes respectively. Then blow dry with nitrogen for later use.

[0067] (2) The cleaned Si substrate is placed in a magnetron sputtering chamber. -6 After 38 sccm of argon and 4 sccm of oxygen were introduced, the sputtering power was set to 50W, gallium oxide was used as the sputtering target, and the sputtering was performed for 180 minutes at a working pressure of 10 mTorr to obtain a 200 nm thick gallium oxide film.

[0068] Repeat steps (1) and (2) to obtain four identical gallium oxide films.

[0069] (3) Three of the four gallium oxide films were annealed at different temperatures in a tube furnace. The heating rate was 2°C / min. The annealing temperatures were 900°C, 1000°C, and 1100°C, respectively. The annealing atmosphere was gallium oxide. After annealing, the films were naturally cooled to room temperature to obtain the final gallium oxide film samples.

[0070] Comparative Example 2

[0071] (1) Take a 10 mm × 10 mm Si substrate with a lattice orientation of (100). Soak the substrate in a 10% volume fraction hydrofluoric acid solution for 10 minutes, then ultrasonically clean it in ultrapure water, ethanol, acetone, and ultrapure water for 15 minutes respectively. Then blow dry with nitrogen for later use.

[0072] (2) Place the cleaned Si substrate into the magnetron sputtering chamber. -6 After 38 sccm of argon and 4 sccm of oxygen were introduced, the sputtering power was set to 120W, gallium oxide was used as the sputtering target, and the sputtering was performed for 180 minutes at a working pressure of 10 mTorr to obtain a gallium oxide film with a thickness of 1000 nm.

[0073] (3) placing the gallium oxide film prepared in step (2) in a tubular furnace for annealing at different temperatures, with a heating rate of 2°C / min, an annealing temperature of 1000°C, and an annealing atmosphere of air. After the annealing is completed, the film is naturally cooled to room temperature to obtain a final sample of a gallium oxide film based on a low-oxygen content gallium oxide buffer layer.

[0074] X-ray diffraction experiments were performed on the gallium oxide film with a low oxygen content gallium oxide buffer layer annealed at different temperatures in Example 1 and the gallium oxide film with a low oxygen content gallium oxide buffer layer that was not annealed, as well as the gallium oxide film annealed at any temperature and the gallium oxide film that was not annealed in Comparative Example 1. The XRD patterns are as follows: Figure 2 As shown, Figure 2 (a), (b), (c), and (d) are the XRD spectra of Example 1 and Comparative Example 1 without annealing, annealing at 900°C, annealing at 1000°C, and annealing at 1100°C, respectively. Figure 2 It can be seen from (a) that there is no obvious gallium oxide diffraction peak in the XRD spectrum of the unannealed sample, indicating that its crystal structure is relatively disordered and it is an amorphous film. Figure 2 As can be seen from (b), (c), and (d), after annealing at 900°C, diffraction peaks in the (400) and (-202) directions can be observed in Comparative Example 1, and as the annealing temperature increases, the diffraction peaks first increase and then decrease, reaching a peak value at 1000°C. After the buffer layer is provided by magnetron sputtering in Example 1, the law of the change of the diffraction peak intensity with temperature remains basically unchanged, but compared with Comparative Example 1 at the same temperature, the provision of the buffer layer greatly improves the diffraction peak intensity and improves the crystallinity of the film.

[0075] The half-peak widths of the (400) and (-202) directions of the gallium oxide films prepared in Example 1 and Comparative Example 1 after annealing at different temperatures are compared. Figure 3 As shown, Figure 3 (a) is a comparison of the half-peak width of the (400) crystal phase. Figure 3 (b) in the figure is a comparison of the half-peak width of the (-202) crystal phase.

[0076] According to Scherrer's formula:

[0077]

[0078] Where D is the grain size; K is the shape factor (usually taken as 0.9); λ is the wavelength of the X-ray; β is the half-width at half maximum (FWHM) of the diffraction peak; and θ is the diffraction angle.

[0079] The smaller the half-width, the larger the grain size, which means that there are fewer grain boundaries in the gallium oxide film and the crystal structure is more complete. In Example 1, the buffer layer is provided to make the grain size of the gallium oxide film larger, and the electrical and optical properties are better than those of the comparative example.

[0080] Figure 4 The Raman spectra of the gallium oxide films prepared in Example 2 and Comparative Example 2 show that, according to group theory, there are 15 optical phonons in the monoclinic β-Ga2O3 that are Raman active, which can be divided into 10 Ag modes and 5 Bg modes according to the arrangement and vibration mode of the Ga-O covalent bond. Figure 4 As shown, the stronger the Raman peak and the more complete the number of Raman peaks that can be observed, the more its crystal structure conforms to the monoclinic β-Ga2O3. Compared with Comparative Example 2, the buffer layer in Example 2 greatly improves the Raman peak intensity and the completeness of the Raman spectrum of the gallium oxide film. Therefore, Raman spectroscopy can also be used to prove that the buffer layer can obtain a better quality gallium oxide film.

[0081] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a gallium oxide thin film based on a low-oxygen-content gallium oxide buffer layer, characterized in that: The following steps are involved: 1) Under an argon atmosphere, magnetron sputtering is performed on the surface of a substrate using gallium oxide as a target material to obtain a substrate with a low-oxygen-content gallium oxide buffer layer; 2) in a mixed atmosphere of oxygen and argon, magnetron sputtering is performed on the surface of the low-oxygen-content gallium oxide buffer layer of the substrate with the low-oxygen-content gallium oxide buffer layer using gallium oxide as a target material to obtain a gallium oxide film; 3) Annealing the gallium oxide film prepared in step 2) to obtain a gallium oxide film based on a low-oxygen-content gallium oxide buffer layer.

2. The method for preparing a gallium oxide thin film based on a low-oxygen-content gallium oxide buffer layer according to claim 1, characterized in that: The parameters of the magnetron sputtering described in step 1) are as follows: The power of the radio frequency power supply is 20 to 120 W, the flow rate of the rare gas is 20 to 50 sccm, the working gas pressure is 5 to 15 mTorr, and the rotation rate of the substrate is 10 to 30 rad / min.

3. The method for preparing a gallium oxide thin film based on a low-oxygen-content gallium oxide buffer layer according to claim 2, characterized in that: The substrate in step 1) is a Si substrate or a SiO2 substrate.

4. The method for preparing a gallium oxide thin film based on a low oxygen content gallium oxide buffer layer according to claim 3, characterized in that: The thickness of the low oxygen content gallium oxide buffer layer in step 1) is 10-400 nm.

5. A method for preparing a gallium oxide thin film based on a low-oxygen-content gallium oxide buffer layer according to any one of claims 2 to 4, characterized in that: The parameters of the magnetron sputtering in step 2) are as follows: The flow rate of the rare gas is 20 to 50 sccm, the flow rate of the oxygen is 0 to 8 sccm, and the working gas pressure is 5 to 15 mTorr, wherein the flow rate of the oxygen is not 0; The power of the radio frequency power supply is 20 to 120 W, and the rotation speed of the substrate is 10 to 30 rad / min.

6. The method for preparing a gallium oxide thin film based on a low-oxygen-content gallium oxide buffer layer according to claim 5, characterized in that: The gallium oxide film described in step 2) has a thickness of 10 to 1000 nm.

7. The method for preparing a gallium oxide thin film based on a low oxygen content gallium oxide buffer layer according to claim 6, characterized in that: The temperature of the annealing treatment in step 3) is 900-1100° C., the heating rate is 0.5-20° C. / min, and the holding time is 0.5-4h.

8. The method for preparing a gallium oxide thin film based on a low-oxygen-content gallium oxide buffer layer according to claim 7, characterized in that: The atmosphere of the annealing treatment in step 3) includes one or more of air, oxygen, nitrogen and argon.

9. A gallium oxide thin film based on a low oxygen content gallium oxide buffer layer prepared by the method for preparing a gallium oxide thin film based on a low oxygen content gallium oxide buffer layer according to any one of claims 1 to 8.

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