A Si:Ga2O3 thin film and its preparation method

Abstract

This application relates to the field of semiconductor thin film materials technology, specifically disclosing a Si:Ga2O3 thin film and its preparation method. The Si:Ga2O3 thin film provided in this application includes a substrate and an epitaxial thin film grown on the substrate; in the Si:Ga2O3 thin film, the molar ratio of Si atoms to Ga atoms is (6.97 × 10⁻⁶). ‑6 ~9.06×10 ‑2 The above-mentioned method for preparing Si:Ga2O3 thin films includes the following steps: cleaning the Fe:Ga2O3 substrate, placing the Fe:Ga2O3 substrate in an MOCVD reaction chamber, using an organic gallium compound as the gallium source, an inorganic silicon source as the dopant source, and argon as the carrier gas, heating the reaction chamber to grow an epitaxial thin film on the surface of the Fe:Ga2O3 substrate; and obtaining the Si:Ga2O3 thin film through in-situ annealing. The Si:Ga2O3 thin film preparation method provided in this application can achieve precise control of the Si atomic flow rate, and the obtained Si:Ga2O3 thin film has low surface roughness and controllable electrical parameters, which can meet the fabrication requirements of different types of power devices.

Description

Technical Field

[0001] This application relates to the field of semiconductor thin film materials technology, specifically to a Si:Ga2O3 thin film and its preparation method. Background Technology

[0002] With the continuous development of information technology, semiconductor technology has become one of the most important technologies in the world today. Semiconductors are materials with controllable conductivity at room temperature, falling between that of conductors and insulators. They are commonly used to manufacture semiconductor devices and integrated circuits. Gallium oxide (Ga2O3) is a wide-bandgap semiconductor material with a direct bandgap. Due to its unique advantages in voltage withstand, current, power, and loss, it plays a significant role in power electronic devices such as SBDs, field-effect transistors, and inverters.

[0003] In recent years, researchers have further improved the electrical parameters and practical performance of gallium oxide by doping it with elements such as Si, Zn, Al, and Fe. Si-doped Ga2O3 thin films (Si:Ga2O3) are one such method. Currently, various methods for preparing Si:Ga2O3 thin films have been disclosed both domestically and internationally. For example, some literature reports that: first, SiO2 and Ga2O3 polycrystalline powders are mixed and calcined using a solid-state sintering method to obtain a Si-doped Ga2O3 polycrystalline target; then, a pulsed laser sputtering method is used to deposit a Si:Ga2O3 epitaxial thin film on a substrate by bombarding the Si-doped Ga2O3 polycrystalline target. However, the above methods have problems such as slow deposition rate and difficulty in target preparation, and the obtained Si:Ga2O3 thin films have a high Si doping level (≥0.5 mol%), making it difficult to meet the requirements of high-voltage power devices above 3000V. Some reports also suggest that metal-organic chemical vapor deposition (MOCVD) can be used to grow epitaxial films on the substrate surface. The above method usually uses organic materials (e.g., TEOS) as silicon doping sources. However, due to the limitations of equipment design, this method cannot achieve precise control of the amount of silicon doping source, that is, it cannot obtain Si:Ga2O3 films with Si doping content <0.5mol%.

[0004] Therefore, there is an urgent need to provide a method for preparing Si:Ga2O3 thin films to obtain Si:Ga2O3 thin films with Si doping content <0.5mol%, thereby meeting the application requirements of high voltage-resistant power devices above 3000V. Summary of the Invention

[0005] To address the issue of high Si doping in Si:Ga2O3 thin films in related technologies, this application provides a Si:Ga2O3 thin film and its preparation method.

[0006] In a first aspect, this application provides a Si:Ga2O3 thin film, which adopts the following technical solution:

[0007] A Si:Ga₂O₃ thin film includes an Fe:Ga₂O₃ substrate and an epitaxial thin film grown on the substrate; wherein the molar ratio of Si atoms to Ga atoms in the Si:Ga₂O₃ thin film is (6.97 × 10⁻⁶). -6 ~9.06×10 -2 ): 100.

[0008] This application provides a Si:Ga2O3 thin film in which the molar ratio of Si atoms to Ga atoms is only 6.97 × 10⁻⁶. -6 ~9.06×10 -2 The molar ratio of Si:Ga2O3 thin films is 100, while the carrier concentration of such films is 6 × 10⁻⁶. 17 ~1.2×10 20 The resistivity is <0.4Ω·cm. Therefore, the Si:Ga2O3 thin film provided in this application has low silicon doping, a wide range of carrier concentrations, and low resistivity, which can meet the application requirements of high-voltage, high-power, and low-loss devices such as SBDs and MOSFETs.

[0009] Optionally, the substrate is a (010) oriented Fe:Ga2O3 substrate.

[0010] In this application, homogeneous epitaxy is performed on a (010) oriented Fe:Ga2O3 substrate, which can effectively avoid lattice mismatch and thermal mismatch between the substrate and the epitaxial layer, thereby obtaining an epitaxial film with high lattice matching degree and tight inter-lattice bonding, and the grown epitaxial film is not easy to fall off.

[0011] Furthermore, the molar ratio of Si atoms to Ga atoms is (3.16 × 10⁻⁶). -5 ~8.75×10 -3 ): 100.

[0012] In this application, the molar ratio of Si atoms to Ga atoms is further controlled within the above-mentioned range, and the resistivity of the obtained Si:Ga2O3 thin film can be as low as below 0.1 Ω·cm.

[0013] In this application, the electrical parameters of the epitaxial thin film mainly include: carrier concentration, mobility, conductivity, and resistivity. Charge carriers are current-carrying particles that directly affect the conductivity of semiconductor materials. Carrier concentration refers to the number of charge carriers per unit volume. A higher carrier concentration indicates higher conductivity of the semiconductor material. Carrier mobility refers to the average drift velocity of charge carriers under the influence of an electric field. Mobility is an important parameter reflecting the conductivity of charge carriers in a semiconductor; for the same doping concentration, a higher carrier mobility indicates higher conductivity of the semiconductor material. Conductivity is affected by carrier concentration and shows the same trend as carrier concentration. Higher resistivity indicates poorer surface conductivity.

[0014] In this application, the epitaxial thin film has a layer thickness of 200±10 nm and a carrier concentration of 6×10⁻⁶. 17 ~1.2×10 20 cm -3 The resistivity is <0.4Ω·cm.

[0015] Secondly, this application provides a method for preparing Si:Ga2O3 thin films, employing the following technical solution:

[0016] A method for preparing a Si:Ga2O3 thin film includes the following steps: cleaning a Fe:Ga2O3 substrate; then placing the Fe:Ga2O3 substrate in an MOCVD reaction chamber, using an organic gallium compound as a gallium source, inorganic silicon as a silicon doping source, and argon as a carrier gas, heating the reaction chamber to grow an epitaxial thin film on the surface of the Fe:Ga2O3 substrate; finally, obtaining the Si:Ga2O3 thin film by in-situ annealing.

[0017] This application provides a method for preparing Si:Ga2O3 thin films. The method uses (010) oriented Fe:Ga2O3 as a substrate, an organogallium compound as a gallium source, and inorganic silicon as a silicon dopant source. A gallium oxide homoepitaxial thin film is grown on the substrate surface via metal-organic chemical vapor deposition. This method enables precise control of the silicon dopant source amount, and the obtained Si:Ga2O3 thin film has a smooth and dense surface, uniform thickness, and tight lattice bonding with high matching degree.

[0018] In this application, an inorganic silicon source control system is connected to the MOCVD equipment to achieve precise control of the silicon doping source amount.

[0019] Furthermore, during the epitaxial film growth process, the flow rate of Si atoms entering the reaction chamber is 9.8 × 10⁻⁶. -12 ~1.2×10 -7 The flow rate of Ga atoms entering the reaction chamber is 1.4 × 10 mol / min. -4 ~1.5×10 -4mol / min.

[0020] In this application, the molar ratio of Si atoms to Ga atoms can be controlled by adjusting the flow rates of silane, argon gas, and the gallium source. By controlling the flow rates of Si atoms and Ga atoms within the aforementioned range, this application maintains the molar ratio of Si atoms to Ga atoms at (6.97 × 10⁻⁶). -6 ~9.06×10 -2 Within the range of 100 nm, the obtained Si:Ga2O3 thin films exhibit good surface roughness, thickness uniformity, and electrical properties, with a surface roughness ≤ 6.8 nm, a thickness difference < 10 nm, and a carrier concentration of 6 × 10⁻⁶. 17 ~1.2×10 20 cm -3 The resistivity is <0.4Ω·cm.

[0021] In one specific implementation, the flow rate of Si atoms entering the reaction chamber can be 9.8 × 10⁻⁶. - 12 mol / min, 4.44×10 -11 mol / min, 8.91×10 -11 mol / min, 4.25×10 -10 mol / min, 3.43×10 -9 mol / min, 1.23×10 -8 mol / min, 4.78×10 -8 mol / min or 1.27×10 -7 mol / min.

[0022] In one specific implementation, the flow rate of Ga atoms entering the reaction chamber is 1.41 × 10⁻⁶. -4 mol / min.

[0023] Furthermore, the flow rate of Si atoms entering the reaction chamber can be 4.44 × 10⁻⁶. -11 ~1.2×10 -8 mol / min, the molar ratio of Si atoms to Ga atoms is (3.16 × 10⁻⁶). -5 ~8.75×10 -3 With a resistivity of 100, the obtained Si:Ga2O3 thin film has a lower resistivity, which is <0.1Ω·cm.

[0024] Furthermore, the organogallium compound is selected from one or both of trimethylgallium and triethylgallium; the inorganic silicon is selected from one or both of silane and silane.

[0025] Furthermore, the growth temperature inside the reaction chamber is 600-850℃, the growth pressure is 20-30 Torr, and the oxygen concentration is 99.999%.

[0026] Furthermore, the in-situ annealing atmosphere is nitrogen or oxygen, and the in-situ annealing time is 25-40 minutes.

[0027] Preferably, the atmosphere for the in-situ annealing is nitrogen.

[0028] In this application, annealing in a nitrogen atmosphere can further improve the activation efficiency of Si atoms, thereby resulting in a higher carrier concentration and lower resistivity in the epitaxial film.

[0029] Furthermore, the specific steps for cleaning the Fe:Ga2O3 substrate are as follows: Select a 010 oriented Fe:Ga2O3 substrate, and ultrasonically clean the Fe:Ga2O3 substrate in acetone, anhydrous ethanol, and deionized water for 15-20 minutes each, and then dry it.

[0030] In summary, this application has the following beneficial effects:

[0031] 1. The method for preparing Si:Ga2O3 thin films in this application uses inorganic silane as the silicon doping source. Compared with the TEOS silicon doping source in related technologies, the amount of silicon doping source is easier to control precisely, enabling micro-doping and obtaining Si:Ga2O3 thin films with Si doping amount <0.5mol%.

[0032] 2. The method for preparing Si:Ga2O3 thin films in this application uses (010) oriented Fe:Ga2O3 as a substrate to grow Ga2O3 homoepitaxial thin films. Therefore, the lattice matching degree is high, the inter-lattice bonding is tight, and the epitaxial layer is not easy to fall off.

[0033] 3. In this application, the molar ratio of Si atoms to Ga atoms in the Si:Ga2O3 thin film is controlled at (6.97 × 10⁻⁶). -6 ~9.06×10 -2 Within the range of 100, the carrier concentration of the obtained Si:Ga2O3 thin film was 6×10⁻⁶. 17 ~1.2×10 20 cm -3 The resistivity is <0.4 Ω·cm; furthermore, the molar ratio of Si atoms to Ga atoms is controlled at (3.16 × 10⁻⁶). -5 ~8.75×10 -3 Within the range of 100, the resistivity of the obtained Si:Ga2O3 thin film is <0.1Ω·cm.

[0034] 4. The preparation method of Si:Ga2O3 thin film provided in this application is simple, easy to operate, and highly controllable. The Si:Ga2O3 thin film obtained has a smooth and dense surface, good crystal quality, and uniform thickness, and can be mass-produced. Attached Figure Description

[0035] Figure 1 This is the AFM image of the epitaxial thin film obtained in Example 1 of this application;

[0036] Figure 2 This is the AFM image of the epitaxial thin film obtained in Example 2 of this application;

[0037] Figure 3 This is the AFM image of the epitaxial thin film obtained in Example 3 of this application;

[0038] Figure 4 This is the AFM image of the epitaxial thin film obtained in Example 4 of this application;

[0039] Figure 5 This is the AFM image of the epitaxial thin film obtained in Example 5 of this application;

[0040] Figure 6 This is the AFM image of the epitaxial thin film obtained in Example 6 of this application;

[0041] Figure 7 This is the AFM image of the epitaxial thin film obtained in Example 7 of this application;

[0042] Figure 8 This is the AFM image of the epitaxial thin film obtained in Example 8 of this application;

[0043] Figure 9 This is the AFM image of the epitaxial thin film obtained in Example 9 of this application;

[0044] Figure 10 This is an AFM image of the epitaxial thin film obtained in Example 10 of this application;

[0045] Figure 11 This is the AFM image of the epitaxial thin film obtained in Example 11 of this application;

[0046] Figure 12 This is the AFM image of the epitaxial thin film obtained in Comparative Example 1 of this application;

[0047] Figure 13 This is the AFM image of the epitaxial thin film obtained in Comparative Example 2 of this application;

[0048] Figure 14 This is the AFM image of the epitaxial thin film obtained in Comparative Example 3 of this application. Detailed Implementation

[0049] This application provides a method for preparing Si:Ga2O3 thin films, comprising the following steps:

[0050] (1) Cleaning Fe:Ga2O3 substrate: Select (010) oriented Fe:Ga2O3 substrate, and ultrasonically clean the Fe:Ga2O3 substrate in acetone, anhydrous ethanol and deionized water for 15-20 min each. After taking it out, rinse off the residual reagents with running deionized water, and finally blow it dry with dry nitrogen gas for later use.

[0051] (2) The Fe:Ga2O3 substrate obtained in step (1) is placed in the MOCVD reaction chamber. An organic gallium compound is used as the gallium source, an inorganic silicon source is used as the dopant source, and argon is used as the carrier gas. In 99.999% high-purity oxygen, the flow rate of Si atoms entering the reaction chamber is set to 9.8 × 10⁻⁶. -12 ~1.2×10 -7 The flow rate of Ga atoms entering the reaction chamber is 1.4 × 10 mol / min. -4 ~1.5×10 -4 The growth rate was mol / min, the growth temperature in the reaction chamber was 600-850℃, the growth pressure was 20-30 Torr, and an epitaxial film with a thickness of 200±10 nm was obtained. After the growth was completed, the film was annealed in situ for 25-40 min in a nitrogen or oxygen atmosphere to obtain a Si:Ga2O3 film.

[0052] The organogallium compound is selected from one or both of trimethylgallium and triethylgallium; the inorganic silicon source is selected from one or both of silane and silane.

[0053] In this application, triethylgallium was purchased from Jiangsu Nanda Optoelectronic Materials Co., Ltd.; silane was purchased from Jiangsu Nanda Optoelectronic Materials Co., Ltd.; the (010) oriented Fe:Ga2O3 substrate is a product manufactured by our company, with product code 2023032000000149 and size of 10mm×15mm; the MOCVD equipment is model AGNITRON AGILIS R&D, and our company has designed and modified the MOCVD equipment to connect an inorganic silicon source control system to the MOCVD equipment; the other raw materials, reagents, solvents, etc. in this application can all be obtained commercially.

[0054] The present application will be further described in detail below with reference to embodiments, performance testing tests and accompanying drawings.

[0055] Example

[0056] Examples 1-8

[0057] Examples 1-8 each provide a Si:Ga2O3 thin film.

[0058] The difference between the above-mentioned Si:Ga2O3 thin films lies in the flow rate of Si atoms entering the reaction chamber, as shown in Table 1 below.

[0059] In this application, the flow rate of Si atoms entering the reaction chamber is achieved by adjusting the flow rates of silane and dilution gas Ar through an inorganic silicon source control system; the flow rate of Ga atoms entering the reaction chamber is achieved by adjusting the flow rate of the carrier gas Ar from the triethylgallium source through an MOCVD control system. That is, the molar ratio of Si atoms to Ga atoms is achieved jointly by the flow rates of silane, triethylgallium, and Ar.

[0060] The preparation method of Si:Ga2O3 thin films provided in Examples 1-8 includes the following steps:

[0061] (1) Cleaning of Fe:Ga2O3 substrate: Select Fe:Ga2O3 substrate with (010) orientation, and clean the Fe:Ga2O3 substrate by ultrasonic cleaning in acetone, anhydrous ethanol and deionized water for 20 min each. After taking it out, rinse off the residual reagents with running deionized water, and finally dry it with dry nitrogen gas for later use.

[0062] (2) The Fe:Ga2O3 substrate obtained in step (1) was placed in the MOCVD reaction chamber. Triethylgallium was used as the gallium source, silane as the dopant source, and argon as the carrier gas. In 99.999% high-purity oxygen, the flow rates of Si atoms entering the reaction chamber and Ga atoms entering the reaction chamber were set as shown in Table 1. The growth temperature in the reaction chamber was 750℃ and the growth pressure was 25 Torr. An epitaxial film with a thickness of 200 nm was obtained. After the growth was completed, the film was annealed in situ in an oxygen atmosphere for 30 min to obtain the Si:Ga2O3 film.

[0063] Table 1. Flow rates of Si atoms entering the reaction chamber in Examples 1-8

[0064]

[0065]

[0066] Examples 9-11

[0067] Examples 9-11 provide a method for preparing Si:Ga2O3 thin films.

[0068] Examples 9, 10, and 11 were carried out according to the methods of Examples 1, 2, and 4, with the difference that the in-situ annealing atmosphere was replaced with nitrogen.

[0069] Comparative Example 1

[0070] Comparative Example 1 provides a Si:Ga2O3 thin film.

[0071] The above-mentioned method for preparing Si:Ga2O3 thin films includes the following steps:

[0072] (1) Target material synthesis: Weigh 0.0113g of SiO2 powder and 6.9947g of Ga2O3 powder, i.e., Si content is 0.5%, put them into a mortar and grind them evenly. Then pour the evenly mixed powder into a stainless steel mold and press it into a round cake with a diameter of 1 inch using a tablet press with a pressure of 8MPa. Then put it into a high-temperature muffle furnace and calcine it at 1350℃ for 24h with a heating rate of 10℃ / min and a cooling rate of 5℃ / min.

[0073] (2) Clean a 5×5mm single-sided polished Ga2O3 substrate with acetone, isopropanol and deionized water for 1 min, and dry it with a nitrogen gun. Fix the clean substrate on the sample stage with silver paste and bake at 200℃ for 15 min. After the silver paste is completely dry, send the sample stage into the vacuum chamber of the pulsed laser deposition system.

[0074] (3) Adjust the distance between the target and the substrate to 50 mm. First, use a mechanical pump to evacuate the gas pressure inside the cavity to below 10 Pa, then use a molecular pump to evacuate the vacuum to 10 Pa. -5 Pa. Turn on the heater and heat the sample stage to 650°C at a heating rate of 25°C / min, and maintain the temperature constant.

[0075] (4) Turn on the flow rate controller to introduce oxygen into the vacuum chamber, and use the bypass valve to fine-tune the gas pressure inside the chamber to maintain the background oxygen partial pressure at 1 Pa. Set the laser energy to 200 mJ, the pulse number to 10000 pulses, and the pulse frequency to 5 Hz. Block the sample stage with a baffle, turn on the laser, and first bombard the target material with the laser for 8 minutes to remove surface contaminants. After that, unscrew the baffle and begin the formal deposition of the thin film on the Ga2O3 substrate.

[0076] (5) After deposition, maintain the background oxygen partial pressure at 1 Pa, cool the sample stage to below 200 °C at a cooling rate of 25 °C / min, and then use a molecular pump to evacuate the cavity to restore the background vacuum. -5 Pa. The sample stage was removed to obtain a 0.5 mol% Si-doped Si:Ga2O3 thin film with a thickness of 200 nm.

[0077] Comparative Example 2

[0078] A Si:Ga2O3 thin film is provided.

[0079] The silicon doping source used in the above Si:Ga2O3 thin film is the organic substance tetraethoxysilane (TEOS).

[0080] The method for preparing the Si:Ga2O3 thin film provided in Comparative Example 2 was carried out according to the method of Example 1, except that: the silicon doping source tetraethoxysilane (TEOS) used in step (2) was a liquid metal-organic compound source, and the Si atoms entering the reaction chamber were adjusted by the MOCVD control system to regulate the flow rate of the carrier gas Ar gas of the TEOS source, and finally the Si:Ga2O3 thin film was obtained; in this Si:Ga2O3 thin film, the molar ratio of Si atoms to Ga atoms was 5.05 × 10⁻⁶. -4 :100.

[0081] Comparative Example 3

[0082] Comparative Example 3 provides a Ga2O3 thin film.

[0083] Comparative Example 3 was carried out according to the method of Example 1, except that the flow rate of Si atoms entering the reaction chamber in step (2) was 0.

[0084] The epitaxial film obtained in Comparative Example 3 was an unintentionally doped Ga2O3 film.

[0085] Performance testing

[0086] The physical and electrical properties of the Si:Ga2O3 films obtained in Examples 1-11, Comparative Examples 1-2, and the Ga2O3 film obtained in Comparative Example 3 were tested, and the results are shown in Table 2 below.

[0087] 1. Physical properties

[0088] (1) Surface roughness: The Si:Ga2O3 films obtained in Examples 1-11, Comparative Examples 1-3, and the Ga2O3 film obtained in Comparative Example 3 were tested using AFM (Oxford Instruments Technology (Shanghai) Co., Ltd., model: MFP-3D Origin). The results are as follows: Figure 1-14 As shown.

[0089] (2) Thickness uniformity: The thickness of the epitaxial film was detected by an ellipsometry (Wuhan Yiguang Technology Co., Ltd., model: SE-Mapping-L). The thickness of the epitaxial film was recorded 200±x at different positions. The larger the x value, the worse the thickness uniformity of the epitaxial film.

[0090] 2. Electrical performance: The carrier concentration, mobility, conductivity and resistivity of the Si:Ga2O3 thin film were tested using a Hall effect tester of model HMS-3000 and with reference to the working principle of van der Berg's law.

[0091] Table 2 Electrical parameters of the epitaxial layers of Si:Ga2O3 thin films in Examples 1-11 and Comparative Examples 1-2

[0092]

[0093]

[0094] According to the test results in Table 2, in Examples 1-11 of this application, the molar ratio of Si atoms to Ga atoms was controlled at (6.97 × 10⁻⁶) through precise control of the Si atom flux. -6 ~9.06×10 -2 The surface roughness was ≤6.8nm, the thickness difference was <10nm, and the carrier concentration was >5×10⁻⁶. 17 cm -3 Si:Ga2O3 thin films with resistivity < 0.4 Ω·cm.

[0095] The test results of Examples 1-8 show that with the increase of Si atom doping, the carrier concentration of the epitaxial film first increases and then decreases, while the resistivity first decreases and then increases. This is because Si atom doping can improve the electrical properties of the epitaxial film. However, when the Si atom doping is too high, some Si atoms are oxidized to form SiO2 during annealing in an oxygen atmosphere, which leads to a decrease in the electrical properties of the epitaxial film. Further comparison reveals that Examples 2-6 further controlled the molar ratio of Si atoms to Ga atoms to (3.16 × 10⁻⁶)⁻¹. -5 ~8.75×10 -3 Within the range of 100, the resistivity of the obtained epitaxial film is lower, with a resistivity <0.1Ω·cm.

[0096] The test results of Examples 1-2, 4, and 9-11 show that the electrical properties of the epitaxial films obtained in Examples 9-11 using nitrogen as the annealing atmosphere are better than those of the epitaxial films obtained in Examples 1-2 and 4 using oxygen as the annealing atmosphere. This is because annealing in a nitrogen atmosphere can further improve the activation efficiency of Si atoms, thereby slightly increasing the carrier concentration of the epitaxial film.

[0097] Comparative Example 1 uses pulsed laser sputtering to prepare epitaxial thin films, which has a long process flow and slow deposition rate. Furthermore, the Si doping content in the obtained Si:Ga2O3 thin film is 0.5 mol%, which cannot meet the requirements of high-voltage power devices with a withstand voltage of over 3000V.

[0098] Comparative Example 2 uses TEOS as the silicon doping source. TEOS is a liquid metal-organic compound source, therefore, appropriate and stable vapor pressure and suitable thermal decomposition temperature are required during preparation to achieve Si doping. Furthermore, it is significantly affected by the environment, and controlling trace doping is extremely difficult; the molar ratio of Si atoms to Ga atoms can only reach a minimum of 5.05 × 10⁻⁶. -4:100; In addition, the carrier concentration levels achieved in Comparative Example 2 and Example 3 are similar, but the Si atom doping amount in Example 3 is much smaller than that in Comparative Example 2, indicating that the preparation method of Si:Ga2O3 thin film of this application can achieve micro-control of Si atom flux and obtain Ga2O3 thin film with smaller Si atom doping amount.

[0099] The carrier concentration of the unintentionally doped Ga2O3 film obtained in Comparative Example 3 was only 5.924 × 10⁻⁶. 16 cm -3 The resistivity is as high as 0.6476 Ω·cm. Therefore, it can be seen that the method for preparing Si:Ga2O3 thin films provided in this application uses metal-organic chemical vapor deposition and inorganic silicon as the silicon doping source, which can achieve trace doping of Si atoms, and the obtained Si:Ga2O3 thin films have less doping, lower surface roughness, better thickness uniformity, and better electrical properties.

[0100] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A Si:Ga2O3 thin film, characterized in that, The Si:Ga2O3 thin film includes a substrate and an epitaxial thin film grown on the substrate; in the Si:Ga2O3 thin film, the molar ratio of Si atoms to Ga atoms is (6.97 × 10⁻⁶). -6 ~9.06×10 -2 ): 100; The substrate is a (010) oriented Fe:Ga2O3 substrate; The method for preparing the Si:Ga2O3 thin film includes the following steps: cleaning the Fe:Ga2O3 substrate; then placing the Fe:Ga2O3 substrate in an MOCVD reaction chamber, using an organic gallium compound as the gallium source, inorganic silicon as the silicon doping source, and argon as the carrier gas, heating the reaction chamber to grow an epitaxial thin film on the surface of the Fe:Ga2O3 substrate; finally, obtaining the Si:Ga2O3 thin film through in-situ annealing. During the epitaxial film growth process, the flow rate of Si atoms entering the reaction chamber is 9.8 × 10⁻⁶. -12 ~1.2×10 -7 The flow rate of Ga atoms entering the reaction chamber is 1.4 × 10 mol / min. -4 ~1.5×10 -4 mol / min.

2. The Si:Ga2O3 thin film according to claim 1, characterized in that, The epitaxial thin film has a thickness of 200±10 nm and a carrier concentration of 6×10⁻⁶. 17 ~1.2×10 20 cm -3 The resistivity is <0.4Ω·cm.

3. The Si:Ga2O3 thin film according to claim 1, characterized in that, The organogallium compound is selected from one or both of trimethylgallium and triethylgallium; the inorganic silicon is selected from one or both of disilane and silane.

4. The Si:Ga2O3 thin film according to claim 1, characterized in that, The growth temperature in the reaction chamber is 600-850℃, the growth pressure is 20-30 Torr, and the oxygen concentration is 99.999%.

5. The Si:Ga2O3 thin film according to claim 1, characterized in that, The in-situ annealing atmosphere is nitrogen or oxygen, and the in-situ annealing time is 25-40 minutes.

6. The Si:Ga2O3 thin film according to claim 1, characterized in that, The atmosphere for the in-situ annealing is nitrogen.

7. The Si:Ga2O3 thin film according to claim 1, characterized in that, The specific steps for cleaning the Fe:Ga2O3 substrate are as follows: Select a (010) oriented Fe:Ga2O3 substrate, and ultrasonically clean the Fe:Ga2O3 substrate in acetone, anhydrous ethanol, and deionized water for 15-20 minutes each, and then dry it.

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