A thin film with epsilon phase gallium oxide heteroepitaxial structure and a preparation method thereof

Abstract

The application provides a thin film with an epsilon phase gallium oxide hetero-epitaxial structure and a preparation method thereof, which comprises, from bottom to top, a substrate layer, a first gallium oxide layer and a second gallium oxide layer; the first gallium oxide layer is an epsilon phase gallium oxide layer doped with magnesium Mg, and the magnesium Mg doping acts as an acceptor type trap in the epsilon phase gallium oxide, effectively compensates for the donor type defects of the epsilon phase gallium oxide, and improves the overall resistivity of the epsilon phase gallium oxide thin film. The preparation method adopts a metal organic chemical vapor deposition method, and the growth temperature of the second gallium oxide layer is higher than that of the first gallium oxide layer; and the molar flow ratio of the magnesium source to the gallium source is controlled to be 0.0001-0.1 during preparation. The application introduces appropriate Mg doping through a nucleation layer stage, so that the Mg acts as an acceptor type trap to compensate for donor type defects, while improving the crystal nucleation quality, reducing dislocations and leakage channels, and realizing the dual optimization of the crystal quality and electrical performance of the epsilon phase gallium oxide thin film, thereby effectively reducing the thin film leakage current and improving the resistivity.

Description

Technical Field

[0001] This invention relates to the field of semiconductor materials technology, and in particular to a thin film having an ε-phase gallium oxide heteroepitaxial structure and its preparation method. Background Technology

[0002] Gallium oxide (GaO), a representative of fourth-generation ultra-wide bandgap semiconductor materials, has a bandgap of approximately 4.5–5.3 eV and a breakdown field strength as high as 8 MV / cm, making it highly valuable for applications in solar-blind ultraviolet detectors and high-voltage power electronic devices. GaO exists in five isomers (α, β, γ, δ, and ε), with the β phase being the most thermodynamically stable. However, its monoclinic crystal structure has low symmetry, posing challenges to heteroepitaxial growth and device fabrication. The ε phase of GaO, on the other hand, belongs to an orthorhombic crystal system and often exhibits a hexagonal-like structure in heteroepitaxial growth. This facilitates heteroepitaxial growth on substrates with hexagonal atomic arrangements, providing good lattice matching with commonly used hexagonal substrates such as sapphire, silicon carbide, and gallium nitride. This provides a theoretical basis for achieving large-area, high-quality thin film growth through heteroepitaxial technology.

[0003] However, current epitaxial growth of ε-phase gallium oxide faces challenges such as poor crystal quality and high background leakage current. Although ε-phase gallium oxide exhibits hexagonal-like symmetry when heteroepitaxially grown on hexagonal substrates, its hexagonal-like structure still exhibits lattice mismatches of 24.2%, 6.4%, and 5.9% with Si(111) substrates, aluminum nitride substrates, and c-plane sapphire substrates, respectively. To address the problem of excessive lattice mismatch in heteroepitaxial growth, a two-step growth method is typically employed, involving the pre-deposition of a low-temperature nucleation layer on the substrate surface as a buffer. However, the crystal quality of the low-temperature nucleation layer itself is usually poor, leading to high-density defects at the interface. These defects often become leakage channels, significantly increasing the leakage current of the device. Intrinsic ε-phase gallium oxide films grown using MOCVD often contain high concentrations of oxygen vacancies and unintentionally doped impurities such as hydrogen atoms due to oxygen partial pressure limitations in the growth environment and high dislocation density in the crystal. This typically results in weak n-type conductivity, leading to significant leakage currents in solar-blind ultraviolet detectors or power devices fabricated from this material in the off-state, severely reducing the device's signal-to-noise ratio and breakdown voltage. Current solutions typically involve doping the heteroepitaxial film with acceptor impurities for compensation. While this effectively improves resistivity, impurity atoms often disrupt lattice periodicity during nucleation layer growth, deteriorating crystal quality and increasing leakage channel density.

[0004] Therefore, there is an urgent need for a heteroepitaxial growth method that can effectively suppress leakage current while maintaining or even improving crystal quality. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a thin film with an ε-phase gallium oxide heteroepitaxial structure and its preparation method. By introducing an appropriate amount of Mg doping during the ε-phase gallium oxide heteroepitaxial growth stage, this invention achieves dual optimization of crystal quality and electrical properties, thereby preparing a low-leakage, high-quality ε-phase gallium oxide heteroepitaxial thin film.

[0006] In a first aspect, the present invention provides a thin film having an ε-phase gallium oxide heteroepitaxial structure, comprising, from bottom to top, a substrate layer, a first gallium oxide layer, and a second gallium oxide layer; The first gallium oxide layer is a magnesium-doped ε-phase gallium oxide layer, and the magnesium-doped ε-phase gallium oxide acts as an acceptor trap, effectively compensating for donor defects in ε-phase gallium oxide and improving the overall resistivity of the ε-phase gallium oxide film.

[0007] Preferably, the substrate is any one of c-plane sapphire, Si(111), silicon carbide, gallium nitride, or Si-AlN composite substrate.

[0008] Preferably, the Si-AlN composite substrate is an epitaxial AlN-on-Si substrate or a bonded Si-on-AlN substrate.

[0009] Preferably, the thickness of the first gallium oxide layer is 10~200nm.

[0010] Preferably, the thickness of the second gallium oxide layer is 0.2~20µm.

[0011] Preferably, the growth temperature of the second gallium oxide layer is higher than that of the first gallium oxide layer.

[0012] Preferably, the second gallium oxide layer is a magnesium-doped ε-phase gallium oxide layer or an intrinsic ε-phase gallium oxide layer.

[0013] In a second aspect, the present invention provides a method for preparing a thin film having an ε-phase gallium oxide heteroepitaxial structure, comprising the following steps: S1) Place the substrate layer inside the reaction chamber of the metal-organic chemical vapor deposition (MOCVD) equipment; S2) Heating raises the temperature of the reaction chamber to 480~580℃; S3) After the temperature of the reaction chamber stabilizes, argon or nitrogen is used as the carrier gas to introduce gallium source, magnesium source and oxygen source into the reaction chamber; the molar flow ratio of magnesium source to gallium source is controlled to be 0.0001~0.1, and a first gallium oxide layer with a thickness of 10~200nm is grown. S4) Stop the flow of magnesium pyrocene and triethylgallium, raise the temperature of the reaction chamber to 580-700℃, making the temperature higher than the growth temperature of the first gallium oxide layer. After the temperature of the reaction chamber stabilizes, continue to flow the gallium source and magnesium source; control the molar flow ratio of the magnesium source to the gallium source to be 0.0001~0.1; or stop the flow of the magnesium source and grow a second gallium oxide layer with a thickness of 0.2~20µm. S5) Stop the carrier gas supply, cool down to room temperature, and then remove the sample to obtain the film.

[0014] Preferably, in step S3), the gallium source is triethylgallium (TEGa).

[0015] Preferably, in step S3), the magnesium source for doping is magnesia-dicenocene.

[0016] Preferably, in step S3), the oxygen source is deionized water or nitrous oxide.

[0017] The beneficial effects of this invention are as follows: 1. In this invention, an appropriate amount of Mg doping is introduced during the nucleation layer growth stage. Mg acts as an acceptor trap in ε-phase gallium oxide, which can effectively compensate for donor defects (oxygen vacancies, hydrogen atoms, etc.) in the film, significantly improving the overall resistivity of the ε-phase gallium oxide film. At the same time, by controlling an appropriate magnesium / gallium molar flow ratio, Mg doping will not disrupt the lattice periodicity, but will instead help improve the crystal quality of the nucleation layer, reduce dislocations and induced leakage channels, and achieve simultaneous optimization of crystal quality and electrical performance. 2. In this invention, Mg doping introduces n-type carriers deeply into the main energy level in the bandgap of ε-phase gallium oxide, which can effectively compensate for defects and background impurities. Combined with the reduction of leakage channels brought about by improved crystal quality, the leakage current of the thin film is significantly reduced under the dual effect, thereby improving the signal-to-noise ratio and breakdown voltage of the device based on the thin film. 3. In the MOCVD growth process, Mg can promote the lateral migration of surface adsorbed atoms, which is beneficial to improving the surface smoothness of the ε phase gallium oxide film and optimizing the surface morphology of the film. 4. The preparation method of this invention can improve the crystal quality on different types of heterogeneous substrates such as c-plane sapphire and Si-AlN composite substrates. The substrate selection is flexible and can be adapted to the fabrication requirements of different semiconductor devices. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the thin film with an ε-phase gallium oxide heteroepitaxial structure in Embodiment 1 of the present invention; Figure 2The image shows the X-ray diffraction (XRD) peak position swing curves of the gallium oxide film with the first gallium oxide layer grown in Example 1 and the gallium oxide film with the first gallium oxide layer grown in Comparative Example 1. The red curve represents the test result of Example 1, and the black curve represents the test result of Comparative Example 1. Figure 3 The image shows the X-ray diffraction (XRD) peak position swing curves of the gallium oxide film with the second gallium oxide layer grown in Example 1 and the gallium oxide film with the second gallium oxide layer grown in Comparative Example 1. The red curve represents the test result of Example 1, and the black curve represents the test result of Comparative Example 1. Figure 4 The figures show the current-voltage characteristic curves of the ε-phase gallium oxide thin film in Example 1 and the ε-phase gallium oxide thin film in Comparative Example 1; wherein, the red curve represents the test results of Example 1 and the black curve represents the test results of Comparative Example 1. Figure 5 The figures show the current-voltage characteristic curves of the ε-phase gallium oxide thin film in Example 2 and the ε-phase gallium oxide thin film in Comparative Example 2. The curves, from top to bottom, represent: the ε-phase gallium oxide thin film in Comparative Example 2, and the ε-phase gallium oxide thin films in Example 2 with molar flow rates of magnesium source and gallium source of 0.0098, 0.020, 0.030, 0.040 and 0.093, respectively. Figure 6 The images show X-ray diffraction (XRD) peak position swing curves of the ε-phase gallium oxide thin film in Example 3 and the ε-phase gallium oxide thin film in Comparative Example 3. The black curve represents the test result of the ε-phase gallium oxide thin film in Comparative Example 3, while the red, blue, and green curves represent the test results of the ε-phase gallium oxide thin films in Example 3 with molar flow rates of 0.00024, 0.0014, and 0.0031 for magnesium and gallium sources, respectively. Figure 7 This is an atomic force microscopy scan of the ε-phase gallium oxide thin film in Example 1 of the present invention; Figure 8 This is an atomic force microscopy scan of the ε-phase gallium oxide thin film in Comparative Example 2 of the present invention; In the figure, 100 is the substrate layer, 200 is the first gallium oxide layer, and 300 is the second gallium oxide layer. Detailed Implementation

[0019] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings: Example 1

[0020] This embodiment provides a method for preparing a thin film with an ε-phase gallium oxide heteroepitaxial structure. The thin film in this embodiment, from bottom to top, includes a substrate layer 100, a first gallium oxide layer 200, and a second gallium oxide layer 300; as shown... Figure 1 As shown. The method for preparing the thin film includes the following steps: S1) Place the c-plane sapphire substrate 100 inside the reaction chamber of the metal-organic chemical vapor deposition (MOCVD) equipment; S2) Heating raises the temperature of the reaction chamber to 520℃; S3) After the temperature of the reaction chamber stabilizes, triethylgallium, magnesium pyrocene and deionized water are introduced into the reaction chamber using argon as the carrier gas; the molar flow ratio of magnesium pyrocene to triethylgallium is controlled to be 0.0126, and a first gallium oxide layer 200 with a thickness of 50 nm is grown. S4) Stop the flow of magnesia-1,4-diocene and triethylgallium, raise the temperature of the reaction chamber to 620°C, making the temperature higher than the growth temperature of the first gallium oxide layer 200. After the temperature of the reaction chamber stabilizes, continue to flow magnesia-1,4-diocene and triethylgallium; and grow a second gallium oxide layer 300 with a thickness of 0.5µm; the molar flow ratio of the introduced magnesia-1,4-diocene to triethylgallium is 0.0126.

[0021] S5) Stop the carrier gas supply, cool to room temperature, and then remove the sample to obtain a thin film. Example 2

[0022] This embodiment provides a method for preparing a thin film with an ε-phase gallium oxide heteroepitaxial structure, comprising the following steps: S1) Place the c-plane sapphire substrate 100 inside the reaction chamber of the metal-organic chemical vapor deposition (MOCVD) equipment; S2) Heating raises the temperature of the reaction chamber to 520℃; S3) After the temperature of the reaction chamber stabilizes, triethylgallium, magnesia-diocene, and deionized water are introduced into the reaction chamber using argon as the carrier gas; the molar flow ratio of magnesia-diocene to triethylgallium is controlled to be 0.0098, 0.020, 0.030, 0.040, and 0.093 to grow a first gallium oxide layer 200 with a thickness of 50 nm. S4) Stop the flow of magnesia-1,4-diocene and triethylgallium, raise the temperature of the reaction chamber to 620°C, making the temperature higher than the growth temperature of the first gallium oxide layer 200. After the temperature of the reaction chamber stabilizes, continue to flow magnesia-1,4-diocene and triethylgallium; and grow a second gallium oxide layer 300 with a thickness of 0.5µm; the molar flow ratio of the flow of magnesia-1,4-diocene and triethylgallium is 0.0098, 0.020, 0.030, 0.040 and 0.093.

[0023] S5) Stop the carrier gas supply, cool to room temperature, and then remove the sample to obtain a thin film. Example 3

[0024] This embodiment provides a method for preparing a thin film with an ε-phase gallium oxide heteroepitaxial structure, comprising the following steps: S1) The Si-AlN composite substrate 100 is placed in the reaction chamber of the metal-organic chemical vapor deposition (MOCVD) equipment; S2) Heating raises the temperature of the reaction chamber to 520℃; S3) After the temperature of the reaction chamber stabilizes, triethylgallium, magnesium pyrocene and deionized water are introduced into the reaction chamber using argon as the carrier gas; the molar flow ratio of magnesium pyrocene to triethylgallium is controlled to be 0.00024, 0.0014 and 0.0031, and a first gallium oxide layer 200 with a thickness of 50 nm is grown. S4) Stop the flow of magnesia-1,4-diocene and triethylgallium, raise the temperature of the reaction chamber to 620°C, making the temperature higher than the growth temperature of the first gallium oxide layer 200. After the temperature of the reaction chamber stabilizes, continue to flow magnesia-1,4-diocene and triethylgallium; and grow a second gallium oxide layer 300 with a thickness of 0.5µm; the molar flow ratio of the introduced magnesia-1,4-diocene and triethylgallium is 0.00024, 0.0014 and 0.0031.

[0025] S5) Stop the carrier gas supply, cool to room temperature, and then remove the sample to obtain a thin film. Comparative Example 1

[0026] The thin film preparation method provided in this embodiment includes the following steps: S1) Place the c-plane sapphire substrate 100 inside the reaction chamber of the metal-organic chemical vapor deposition (MOCVD) equipment; S2) Heating raises the temperature of the reaction chamber to 520℃; S3) After the temperature of the reaction chamber stabilizes, triethylgallium and deionized water are introduced into the reaction chamber using argon as the carrier gas; a first gallium oxide layer 200 with a thickness of 50 nm is grown. S4) Stop the flow of triethylgallium, raise the temperature of the reaction chamber to 620°C, making the temperature higher than the growth temperature of the first gallium oxide layer 200. After the temperature of the reaction chamber stabilizes, introduce magnesia-cerocenium and triethylgallium; and grow a second gallium oxide layer 300 with a thickness of 0.5µm; the molar flow ratio of the introduced magnesia-cerocenium to triethylgallium is 0.0126.

[0027] S5) Stop the carrier gas supply, cool to room temperature, and then remove the sample to obtain a thin film. Comparative Example 2

[0028] The thin film preparation method provided in this embodiment includes the following steps: S1) Place the c-plane sapphire substrate 100 inside the reaction chamber of the metal-organic chemical vapor deposition (MOCVD) equipment; S2) Heating raises the temperature of the reaction chamber to 520℃; S3) After the temperature of the reaction chamber stabilizes, triethylgallium and deionized water are introduced into the reaction chamber using argon as the carrier gas; a first gallium oxide layer 200 with a thickness of 50 nm is grown. S4) Stop the supply of triethylgallium, raise the temperature of the reaction chamber to 620°C, making the temperature higher than the growth temperature of the first gallium oxide layer 200. After the temperature of the reaction chamber stabilizes, supply triethylgallium and grow a second gallium oxide layer 300 with a thickness of 0.5µm.

[0029] S5) Stop the carrier gas supply, cool to room temperature, and then remove the sample to obtain a thin film. Comparative Example 3

[0030] The thin film preparation method provided in this embodiment includes the following steps: S1) Place 100 layers of the Si-AlN composite substrate inside the reaction chamber of the metal-organic chemical vapor deposition (MOCVD) equipment; S2) Heating raises the temperature of the reaction chamber to 520℃; S3) After the temperature of the reaction chamber stabilizes, triethylgallium and deionized water are introduced into the reaction chamber using argon as the carrier gas; a first gallium oxide layer 200 with a thickness of 50 nm is grown. S4) Stop the supply of triethylgallium, raise the temperature of the reaction chamber to 620°C, making the temperature higher than the growth temperature of the first gallium oxide layer 200. After the temperature of the reaction chamber stabilizes, supply triethylgallium and grow a second gallium oxide layer 300 with a thickness of 0.5µm.

[0031] S5) Stop the carrier gas supply, cool to room temperature, and then remove the sample to obtain a thin film. Example 4

[0032] This embodiment provides a performance analysis of Examples 1-3 and Comparative Examples 1-3, as detailed below: like Figure 2 As shown, the full width at half maximum (FWHM) of the ε-phase gallium oxide (004) peak rocking curve of the magnesium-doped first gallium oxide layer 200 in Example 1 is 0.391°, while the FWHM of the ε-phase gallium oxide (004) peak rocking curve of the undoped first gallium oxide layer 200 in Comparative Example 1 is 0.445°. This indicates that the participation of an appropriate amount of magnesium in the nucleation layer growth process of ε-phase gallium oxide can significantly improve the crystal quality of the nucleation layer and effectively reduce the defect density.

[0033] like Figure 3As shown, the full width at half maximum (FWHM) of the peak rocking curve of the ε-phase gallium oxide thin film (004) with magnesium doped in the first gallium oxide layer 200 in Example 1 is 0.322°, while the FWHM of the peak rocking curve of the ε-phase gallium oxide thin film (004) in Comparative Example 1 is 0.331°. This demonstrates that doping the nucleation layer with an appropriate amount of Mg effectively improves the crystal quality of the nucleation layer; and the high-quality nucleation layer further acts as a template, promoting the orderly growth of subsequent epitaxial layers, thereby improving the overall crystal quality of the thin film.

[0034] like Figure 4 As shown, ohmic contact metal electrodes of the same size were deposited on the magnesium-doped ε-phase gallium oxide film in Example 1 and the intrinsic ε-phase gallium oxide film in Comparative Example 1. Specifically, the metal electrodes used a Ti / Au composite layer and were nested annular in shape with an inner diameter of 60µm and an outer diameter of 70µm. The IV characteristic curves of the films were tested. In Example 1, the magnesium-doped ε-phase gallium oxide film exhibited a current of 3.5nA under a 3V bias; while in Comparative Example 1, the ε-phase gallium oxide film exhibited a current of 3.8nA under a 3V bias. Example 1, through improved crystal quality, reduced leakage channels and effectively suppressed leakage current.

[0035] like Figure 5 As shown, ohmic contact metal electrodes of the same size were deposited on the magnesium-doped ε-phase gallium oxide thin film in Example 2 and the intrinsic ε-phase gallium oxide thin film in Comparative Example 2. Specifically, the metal electrodes used a Ti / Au composite layer and consisted of 40 pairs of interdigitated electrodes to prevent the current from being too small and exceeding the measurement limit. The IV characteristic curves of the thin films were then tested. The intrinsic ε-phase gallium oxide thin film in Comparative Example 2 exhibited a current of 21.5 nA under a 3V bias; while the ε-phase gallium oxide thin films in Example 2 with magnesium and gallium source molar flow ratios of 0.0098, 0.020, 0.030, 0.040, and 0.093, respectively, showed currents of 13.5, 6.6, 4.7, 3.9, and 1.2 nA under a 3V bias. This indicates that, in addition to the improved crystal quality of the nucleation layer reducing leakage channels, Mg introduces n-type carriers deeply embedded in the principal energy level within the bandgap of ε-phase gallium oxide. These carriers effectively compensate for defects in the ε-phase gallium oxide and the introduction of background impurities, thereby significantly improving the resistivity of the thin film. Furthermore, as... Figure 7 , Figure 8 As shown, the property of Mg to promote the lateral migration of surface adsorbed atoms during growth is also beneficial to improving the surface morphology of ε phase gallium oxide films.

[0036] like Figure 6As shown, the full width at half maximum (FWHM) of the peak-position rocking curve of the intrinsic ε-phase gallium oxide film (004) grown on the Si-AlN composite substrate in Comparative Example 3 is 1.022°, while the FWHMs of the peak-position rocking curves of the ε-phase gallium oxide film (004) with magnesium and gallium source molar flow rates of 0.00024, 0.0014, and 0.0031 in Example 3 are 0.996°, 0.978°, and 0.971°, respectively. This data trend proves that the in-situ magnesium doping growth method described in this invention is equally applicable to improving the crystal quality of ε-phase gallium oxide on different types of heterostructure substrates.

[0037] The embodiments and descriptions above are merely illustrative of the principles and preferred embodiments of the present invention. Various changes and modifications may be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A thin film having an ε-phase gallium oxide heteroepitaxial structure, characterized in that, From bottom to top, it includes a substrate layer (100), a first gallium oxide layer (200), and a second gallium oxide layer (300). The first gallium oxide layer (200) is a magnesium-doped ε-phase gallium oxide layer, and the magnesium-doped ε-phase gallium oxide acts as an acceptor trap, effectively compensating for the donor defects of ε-phase gallium oxide and improving the overall resistivity of the ε-phase gallium oxide film.

2. A thin film with an ε-phase gallium oxide heteroepitaxial structure according to claim 1, characterized in that: The substrate layer (100) is any one of c-plane sapphire, Si (111), silicon carbide, gallium nitride, or Si-AlN composite substrate.

3. A thin film with an ε-phase gallium oxide heteroepitaxial structure according to claim 2, characterized in that: The Si-AlN composite substrate is either an epitaxial AlN-on-Si substrate or a bonded Si-on-AlN substrate.

4. A thin film with an ε-phase gallium oxide heteroepitaxial structure according to claim 1, characterized in that: The thickness of the first gallium oxide layer (200) is 10~200nm.

5. A thin film having an ε-phase gallium oxide heteroepitaxial structure according to claim 1, characterized in that: The thickness of the second gallium oxide layer (300) is 0.2~20µm.

6. A thin film having an ε-phase gallium oxide heteroepitaxial structure according to claim 5, characterized in that: The growth temperature of the second gallium oxide layer (300) is higher than that of the first gallium oxide layer (200).

7. A thin film having an ε-phase gallium oxide heteroepitaxial structure according to claim 6, characterized in that: The second gallium oxide layer (300) is a magnesium-doped ε-phase gallium oxide layer or an intrinsic ε-phase gallium oxide layer.

8. A method for preparing a thin film with an ε-phase gallium oxide heteroepitaxial structure, characterized in that, Includes the following steps: S1) The substrate layer (100) is placed in the reaction chamber of the metal-organic chemical vapor deposition (MOCVD) equipment; S2) Heating raises the temperature of the reaction chamber to 480~580℃; S3) After the temperature of the reaction chamber stabilizes, argon or nitrogen is used as the carrier gas to introduce gallium source, magnesium source and oxygen source into the reaction chamber; the molar flow ratio of magnesium source to gallium source is controlled to be 0.0001~0.1, and a first gallium oxide layer with a thickness of 10~200nm (200) is grown. S4) Stop the flow of magnesium pyrocene and triethylgallium, raise the temperature of the reaction chamber to 580-700℃, making the temperature higher than the growth temperature of the first gallium oxide layer (200). After the temperature of the reaction chamber stabilizes, continue to flow the gallium source and magnesium source; control the molar flow ratio of the magnesium source to the gallium source to be 0.0001~0.1; or stop the flow of the magnesium source; grow a magnesium-doped ε-phase second gallium oxide layer (300) or an intrinsic ε-phase second gallium oxide layer (300) with a thickness of 0.2~20µm. S5) Stop the carrier gas supply, cool down to room temperature, and then remove the sample to obtain the film.

9. The method for preparing a thin film with an ε-phase gallium oxide heteroepitaxial structure according to claim 8, characterized in that: In step S3), the gallium source is triethylgallium (TEGa); the doped magnesium source is magnesia-dicenocene.

10. A method for preparing a thin film with an ε-phase gallium oxide heteroepitaxial structure according to claim 8, characterized in that: In step S3), the oxygen source is deionized water or nitrous oxide.

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