Gallium oxide epitaxial wafer and method for manufacturing the same

Abstract

This invention relates to the field of semiconductor technology, specifically disclosing a gallium oxide epitaxial wafer and its preparation method. The preparation method of the gallium oxide epitaxial wafer includes the following steps: S1, placing a (011)-plane gallium oxide substrate in a reaction chamber, introducing a carrier gas, and then introducing oxygen, chlorine, and hydrogen for a first growth; S2, introducing oxygen and hydrogen chloride for a second growth on the first-grown gallium oxide substrate to obtain a gallium oxide epitaxial wafer; wherein, in S1, the flow rate ratio of oxygen to chlorine is (2~3):1; in S2, the flow rate of oxygen is 200~400 sccm, and the flow rate ratio of oxygen to hydrogen chloride is (5~20):1. This invention optimizes the number of growth cycles and growth conditions during the preparation of the gallium oxide epitaxial wafer, reduces epitaxial defect density, improves epitaxial film quality, and realizes the preparation of high-thickness gallium oxide epitaxial wafers with low surface defects and nanoscale surfaces.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a gallium oxide epitaxial wafer and its preparation method. Background Technology

[0002] Gallium oxide (GaO), as a fourth-generation ultra-wide bandgap semiconductor material, has significant application prospects in high-power power electronic devices and optoelectronic devices due to its excellent properties, and has become a new generation of strategic semiconductor material. Currently, the rapid development of GaO power devices has placed higher demands on GaO substrate materials, especially the GaO homoepitaxial layer, which serves as the functional layer of the device. This requires high-speed, high-thickness, and high-quality epitaxial growth to meet the requirements of higher voltage and higher power GaO devices.

[0003] Currently, homoepitaxial gallium oxide (GaO) layers for high-power devices are mainly obtained through high-chloride vapor phase epitaxy (HVPE), which involves epitaxially growing micrometer-scale GaO layers on n-type GaO substrates prepared using the guided-mode method. In HVPE, oxygen is the primary oxygen source, and chlorine or hydrogen chloride is the chlorine source. Due to the anisotropy of monoclinic GaO, different crystal planes exhibit different growth rates, resulting in a striped morphology in the GaO epitaxial layer. Because of the competition between growth and etching on different crystal planes during epitaxial growth, the epitaxial morphology and surface quality are significantly affected by the substrate and epitaxial process. This is especially true for high-thickness epitaxial wafers exceeding 30 μm, where the epitaxial quality deteriorates drastically with increasing thickness. For example, stripe depths increase from tens of nanometers to micrometers, and problems such as micro-groove defects, polycrystalline particle aggregation, and stripe widening occur. This deterioration in epitaxial quality severely impacts the electrical characteristics of subsequent power devices, failing to meet practical application requirements. Therefore, developing a high-thickness GaO epitaxial wafer with low surface defects and a nanometer-scale surface is essential. Summary of the Invention

[0004] In view of this, the present invention provides a gallium oxide epitaxial wafer and its preparation method. The present invention innovatively uses HVPE technology to prepare (011)-plane gallium oxide homoepitaxial wafers. By designing the epitaxial process method, the present invention avoids problems such as groove defects, polycrystalline microparticles, and stripe widening in conventional gallium oxide epitaxial wafers, while simultaneously achieving two-dimensional step flow growth, resulting in nanoscale surface and high-thickness gallium oxide epitaxial wafers. The present invention achieves the preparation of gallium oxide epitaxial wafers with nanoscale surfaces, effectively reducing processing material removal and mechanical damage, while simultaneously achieving rapid, thick-film growth. This provides innovative technical reserves for the preparation of ultra-thick gallium oxide epitaxial wafers exceeding 30 μm, and greatly promotes the improvement of gallium oxide power device performance.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: A method for preparing a gallium oxide epitaxial wafer includes the following steps: S1. Place the (011) surface gallium oxide substrate in the reaction chamber, introduce a carrier gas with a first preset flow rate, set the pressure in the reaction chamber to a first preset pressure, heat the source region of the reaction chamber to a first preset temperature, heat the growth region to a second preset temperature, and introduce oxygen with a second preset flow rate, chlorine with a third preset flow rate and hydrogen with a fourth preset flow rate for the first growth. S2. Introduce oxygen at a fifth preset flow rate and hydrogen chloride at a sixth preset flow rate to perform a second growth on the gallium oxide substrate grown in the first growth, to obtain a gallium oxide epitaxial wafer; In S1, the flow rate ratio of oxygen to chlorine is (2~3):1; In S2, the fifth preset flow rate ranges from 200 to 400 sccm, and the flow rate ratio of oxygen to hydrogen chloride is (5 to 20):1.

[0006] Compared with existing technologies, the gallium oxide epitaxial wafer preparation method provided by this invention innovatively employs a two-stage growth method to suppress epitaxial defects. This invention uses a (011)-plane gallium oxide substrate as the epitaxial substrate. During the first growth stage, the flow ratio of oxygen to chlorine is controlled at 2-3. This specific ratio promotes the reaction of hydrogen chloride with gallium to generate a large amount of gallium chloride, thereby promoting the lateral two-dimensional diffusion of the gallium-oxygen atomic layer and reducing three-dimensional island growth, thus effectively suppressing crystal defects in the early stages of epitaxy. Furthermore, during the second growth stage, the flow ratio of oxygen to hydrogen chloride is controlled at 5-20, and the oxygen flow rate is 200-400 sccm. This specific flow rate promotes the forward reaction of gallium chloride with oxygen to generate gallium oxide, thereby rapidly increasing the growth rate. The combination of the two growth stages ultimately forms a continuous stripe morphology, reducing the epitaxial defect density and improving the quality of the epitaxial film, thus realizing the preparation of a high-thickness gallium oxide epitaxial wafer with low surface defects and a nanoscale surface.

[0007] Preferably, in S1, the first preset flow rate is 6000~8000 sccm.

[0008] Preferably, in S1, the carrier gas includes at least one of nitrogen or argon.

[0009] Preferably, in S1, the first preset pressure is 150~250 mbar.

[0010] Preferably, in S1, the first preset temperature is 850~900℃.

[0011] Preferably, in S1, the second preset temperature is 1000~1050℃.

[0012] Preferably, in S1, the second preset flow rate is 20~60 sccm.

[0013] Preferably, in S1, the third preset flow rate is 10~20 sccm.

[0014] This invention, by limiting the flow rate of oxygen and chlorine, can control slow growth to a certain extent, achieve sufficient lateral migration of atoms, and realize a flat epitaxial layer.

[0015] Preferably, in S1, the flow rate ratio of chlorine to hydrogen is (4~20):1.

[0016] The present invention further limits the flow ratio of chlorine and hydrogen to ensure that hydrogen achieves micro-etching without damaging the substrate surface, thereby suppressing the generation of defects.

[0017] Preferably, in S1, the time for the first growth is 1 to 2 hours.

[0018] Preferably, in S2, the sixth preset flow rate is 20~40 sccm.

[0019] Preferably, in S2, the second growth time is 2-5 hours.

[0020] This invention provides a gallium oxide epitaxial wafer, which is prepared by the above-described method for preparing gallium oxide epitaxial wafers.

[0021] The method for preparing gallium oxide epitaxial wafers provided by this invention includes two growth processes on (011)-plane gallium oxide as a substrate. In the first growth process, oxygen, chlorine, and hydrogen are used as raw materials. The flow ratio of oxygen to chlorine is controlled at (2~3):1 to ensure a low flow rate of raw materials. A trace amount of hydrogen is also used as an auxiliary agent. The low flow ratio of oxygen and chlorine ensures sufficient chlorine to react with gallium to generate gallium chloride, thus forming a large number of gallium nucleation sites. Simultaneously, the relatively low flow rates of oxygen and chlorine control the slow growth of the substrate, ensuring sufficient lateral migration of atoms and promoting the coherence of the gallium-oxygen atomic layer. The trace amount of hydrogen helps to etch the surface, removing surface defects and exposing a perfect surface, thereby obtaining a nanoscale two-dimensional atomic layer.

[0022] When transitioning to the second-step growth method, oxygen and hydrogen chloride are used as source gases, with the flow ratio of oxygen to hydrogen chloride controlled at (5~20):1. A high flow rate of source gas is maintained, and this high flow ratio and high flow rate of source gas are conducive to generating a large amount of gallium oxide, significantly increasing the growth rate, ensuring sufficient lateral migration of atoms, achieving a flat epitaxial layer, and thus enabling rapid, high-thickness film fabrication. Furthermore, when hydrogen chloride is used as the source gas in this growth step, the gallium oxide epitaxial growth rate is much faster than when chlorine is used, enabling rapid growth of ultra-thick films, shortening growth time, and improving efficiency. Simultaneously, the hydrogen in hydrogen chloride can simultaneously act as a micro-etching agent, suppressing the generation and inheritance of defects during epitaxy, and promoting the fabrication of nanoscale surfaces and high-quality, high-thickness films.

[0023] In the method for preparing gallium oxide epitaxial wafers provided by the present invention, the nucleation growth mode is controlled by adjusting the ratio of chlorine, oxygen and hydrogen, and the epitaxial growth rate and quality are controlled by adjusting the ratio of hydrogen chloride and oxygen, thereby finally obtaining a nanoscale surface, high-thickness (011) surface gallium oxide homoepitaxial wafer. Attached Figure Description

[0024] Figure 1 This is a surface morphology diagram of the gallium oxide epitaxial wafer provided in Embodiment 1 of the present invention; Figure 2 An atomic force microscope image of a gallium oxide epitaxial wafer provided in Embodiment 1 of the present invention; Figure 3 This is a surface morphology diagram of the gallium oxide epitaxial wafer provided in Embodiment 4 of the present invention; Figure 4 This is a surface morphology diagram of the gallium oxide epitaxial wafer provided in Comparative Example 1 of the present invention; Figure 5 This is a surface morphology diagram of the gallium oxide epitaxial wafer provided in Comparative Example 3 of the present invention; Figure 6 The figure shows the forward current-voltage (IV) characteristic curve of the SBD vertical power device fabricated using the gallium oxide epitaxial wafer provided in Example 1 of this invention. Figure 7 The reverse current-voltage (IV) characteristic curve of the SBD vertical power device fabricated using the gallium oxide epitaxial wafer provided in Example 1 of this invention is shown. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] Unless otherwise specified, the raw materials and reagents used in this invention are all conventional commercially available products; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0027] Example 1 This embodiment provides a method for preparing gallium oxide epitaxial wafers, including the following steps: S100: Place the gallium oxide substrate on the (011) side into the epitaxial growth system, use nitrogen gas at 8000 sccm as the carrier gas, and set the pressure in the epitaxial growth system to 150 mbar. S200: Set the source region temperature of the epitaxial growth system to 900℃ and the growth region temperature to 1000℃; S300: After the temperature stabilizes, oxygen, chlorine and hydrogen are used as source gases. Oxygen, chlorine and hydrogen are introduced at the same time. The flow ratio of oxygen and chlorine is controlled at 3:1. The flow rate of oxygen is set to 60 sccm, the flow rate of chlorine is 20 sccm and the flow rate of hydrogen is 5 sccm. S400: Set the growth time to 1 hour; S500: After the growth in step S400 is completed, oxygen and hydrogen chloride are used as source gases. Oxygen and hydrogen chloride are introduced in situ at the same time, and the flow rate ratio of oxygen to hydrogen chloride is controlled at 12:1. The flow rate of oxygen is set to 360 sccm and the flow rate of hydrogen chloride is set to 30 sccm. S600: Set the growth time to 3 hours; S700: After epitaxial growth is complete, set the epitaxial growth system temperature to 23℃ and wait for it to cool naturally to room temperature.

[0028] Example 2 This embodiment provides a method for preparing gallium oxide epitaxial wafers, including the following steps: S100: Place the gallium oxide substrate on the (011) side into the epitaxial growth system, use nitrogen gas at 6000 sccm as the carrier gas, and set the pressure in the epitaxial growth system to 250 mbar. S200: Set the source region temperature of the epitaxial growth system to 850℃ and the growth region temperature to 1050℃; S300: After the temperature stabilizes, oxygen, chlorine and hydrogen are used as source gases. Oxygen, chlorine and hydrogen are introduced at the same time. The flow ratio of oxygen and chlorine is controlled to be 2:1. The flow rate of oxygen is set to 20 sccm, the flow rate of chlorine is 10 sccm and the flow rate of hydrogen is 1 sccm. S400: Set the growth time to 2 hours; S500: After the growth in step S400 is completed, oxygen and hydrogen chloride are used as source gases. Oxygen and hydrogen chloride are introduced in situ at the same time, and the flow rate ratio of oxygen to hydrogen chloride is controlled at 20:1. The flow rate of oxygen is set to 400 sccm and the flow rate of hydrogen chloride is set to 20 sccm. S600: Set the growth time to 5 hours; S700: After epitaxial growth is complete, set the epitaxial growth system temperature to 23℃ and wait for it to cool naturally to room temperature.

[0029] Example 3 This embodiment provides a method for preparing gallium oxide epitaxial wafers, including the following steps: S100: Place the gallium oxide substrate on the (011) side into the epitaxial growth system, use argon gas at 7000 sccm as the carrier gas, and set the pressure in the epitaxial growth system to 200 mbar. S200: Set the source region temperature of the epitaxial growth system to 850℃ and the growth region temperature to 1000℃; S300: After the temperature stabilizes, oxygen, chlorine and hydrogen are used as source gases. Oxygen, chlorine and hydrogen are introduced at the same time. The flow ratio of oxygen and chlorine is controlled to be 2:1. The flow rate of oxygen is set to 40 sccm, the flow rate of chlorine is 20 sccm and the flow rate of hydrogen is 5 sccm. S400: Set the growth time to 2 hours; S500: After the growth in step S400 is completed, oxygen and hydrogen chloride are used as source gases. Oxygen and hydrogen chloride are introduced in situ at the same time, and the flow rate ratio of oxygen to hydrogen chloride is controlled at 10:1. The flow rate of oxygen is set to 400 sccm and the flow rate of hydrogen chloride is set to 40 sccm. S600: Set the growth time to 4 hours; S700: After epitaxial growth is complete, set the epitaxial growth system temperature to 23℃ and wait for it to cool naturally to room temperature.

[0030] Example 4 This embodiment provides a method for preparing gallium oxide epitaxial wafers, which differs from Embodiment 1 in that the hydrogen flow rate in S300 is increased, including the following steps: S100: Place the gallium oxide substrate on the (011) side into the epitaxial growth system, use nitrogen gas at 8000 sccm as the carrier gas, and set the pressure in the epitaxial growth system to 150 mbar. S200: Set the source region temperature of the epitaxial growth system to 900℃ and the growth region temperature to 1000℃; S300: After the temperature stabilizes, oxygen, chlorine and hydrogen are used as source gases. Oxygen, chlorine and hydrogen are introduced at the same time. The flow ratio of oxygen and chlorine is controlled at 3:1. The flow rate of oxygen is set to 60 sccm, the flow rate of chlorine is 20 sccm and the flow rate of hydrogen is 20 sccm. S400: Set the growth time to 1 hour; S500: After the growth in step S400 is completed, oxygen and hydrogen chloride are used as source gases. Oxygen and hydrogen chloride are introduced in situ at the same time, and the flow rate ratio of oxygen to hydrogen chloride is controlled at 12:1. The flow rate of oxygen is set to 360 sccm and the flow rate of hydrogen chloride is set to 30 sccm. S600: Set the growth time to 3 hours; S700: After epitaxial growth is complete, set the epitaxial growth system temperature to 23℃ and wait for it to cool naturally to room temperature.

[0031] Comparative Example 1 This comparative example provides a method for preparing a gallium oxide epitaxial wafer, which differs from Example 1 in that the flow ratio of oxygen to chlorine in S300 is 10:1, and specifically includes the following steps: S100: Place the gallium oxide substrate on the (011) side into the epitaxial growth system, use nitrogen gas at 8000 sccm as the carrier gas, and set the pressure in the epitaxial growth system to 150 mbar. S200: Set the source region temperature of the epitaxial growth system to 900℃ and the growth region temperature to 1000℃; S300: After the temperature stabilizes, oxygen, chlorine and hydrogen are used as source gases. Oxygen, chlorine and hydrogen are introduced at the same time. The flow ratio of oxygen and chlorine is controlled to be 10:1. The flow rate of oxygen is set to 400 sccm, the flow rate of chlorine is 40 sccm and the flow rate of hydrogen is 5 sccm. S400: Set the growth time to 1 hour; S500: After the growth in step S400 is completed, oxygen and hydrogen chloride are used as source gases. Oxygen and hydrogen chloride are introduced in situ at the same time, and the flow rate ratio of oxygen to hydrogen chloride is controlled at 12:1. The flow rate of oxygen is set to 360 sccm and the flow rate of hydrogen chloride is set to 30 sccm. S600: Set the growth time to 3 hours; S700: After epitaxial growth is complete, set the epitaxial growth system temperature to 23℃ and wait for it to cool naturally to room temperature.

[0032] Comparative Example 2 This comparative example provides a method for preparing a gallium oxide epitaxial wafer, which differs from Example 1 in that the flow ratio of oxygen to hydrogen chloride in S500 is 100:1, and specifically includes the following steps: S100: Place the gallium oxide substrate on the (011) side into the epitaxial growth system, use nitrogen gas at 8000 sccm as the carrier gas, and set the pressure in the epitaxial growth system to 150 mbar. S200: Set the source region temperature of the epitaxial growth system to 900℃ and the growth region temperature to 1000℃; S300: After the temperature stabilizes, oxygen, chlorine and hydrogen are used as source gases. Oxygen, chlorine and hydrogen are introduced at the same time. The flow ratio of oxygen and chlorine is controlled at 3:1. The flow rate of oxygen is set to 60 sccm, the flow rate of chlorine is 20 sccm and the flow rate of hydrogen is 5 sccm. S400: Set the growth time to 1 hour; S500: After the growth in step S400 is completed, oxygen and hydrogen chloride are used as source gases. Oxygen and hydrogen chloride are introduced in situ at the same time, and the flow rate ratio of oxygen to hydrogen chloride is controlled to be 100:1. The flow rate of oxygen is set to 400 sccm and the flow rate of hydrogen chloride is set to 4 sccm. S600: Set the growth time to 3 hours; S700: After epitaxial growth is complete, set the epitaxial growth system temperature to 23℃ and wait for it to cool naturally to room temperature.

[0033] Comparative Example 3 S100: Place the (011) surface gallium oxide substrate in the reaction chamber, use 5200 sccm nitrogen as the carrier gas, and set the pressure in the reaction chamber to 200 mbar; S200: Heat the epitaxial growth system to ensure the chamber temperature reaches 500℃; S300: After the temperature stabilizes, hydrogen gas is introduced into the chamber to pretreat the substrate, wherein the hydrogen flow rate is 20 sccm and the treatment time is 15 min. S400: After the preset time is reached, stop the hydrogen supply and set the pressure in the chamber to 0 mbar until the hydrogen is completely removed. S500: Reset the pressure in the reaction chamber to 200 mbar, raise the source region temperature of the epitaxial growth system to 850°C, and raise the growth region temperature to 1000°C; S600: After the temperature stabilizes, hydrogen chloride and oxygen are introduced into the chamber as reaction source gases, with the flow rate of hydrogen chloride ranging from 10 sccm and the flow rate of oxygen ranging from 200 sccm. S700: Introduce a small amount of hydrogen gas, with a flow rate of 1 sccm; S800: After epitaxial growth is complete, set the chamber temperature to 23℃ and wait for it to cool naturally to room temperature.

[0034] Example of effect Depend on Figures 1-2As can be seen, the surface morphology of the epitaxial layer of the gallium oxide epitaxial wafer provided by the present invention is flat and free of any structural defects. The thickness of the epitaxial layer is 30.1 μm and the epitaxial speed is 10 μm / h, realizing the rapid and high surface quality preparation of a high-thickness gallium oxide epitaxial layer. Figures 2-3 The image is an atomic force microscope image of a gallium oxide epitaxial wafer with a (011) face. The surface roughness Ra of the epitaxial layer is 7.22 nm, and a nanoscale surface of the epitaxial layer is obtained. The epitaxial layer has high flatness.

[0035] Figure 3 The surface morphology image of the gallium oxide epitaxial wafer provided in Embodiment 4 of the present invention is obtained from... Figure 3 It can be seen that when the hydrogen flow rate is increased during the first growth, a raised quadrilateral defect appears on the surface of the epitaxial layer of the gallium oxide epitaxial wafer. The excessive hydrogen flow rate damages the substrate surface and the defect is not suppressed.

[0036] Figure 4 This is a surface morphology diagram of the gallium oxide epitaxial wafer provided in Comparative Example 1 of the present invention. Figure 4 It can be seen that when the flow ratio of oxygen and chlorine is increased during the first growth, the epitaxial layer of the gallium oxide epitaxial wafer is uneven and has polycrystalline particles (black spot areas) on the surface.

[0037] The epitaxial layer thickness of the gallium oxide epitaxial wafer prepared in Comparative Example 2 was 9 μm. Under these conditions, the epitaxial speed was 3 μm / h and the growth time was 3 h. The gallium oxide epitaxial speed was too slow and the growth efficiency was low, which is not conducive to the preparation of thick films with a thickness of more than 30 μm required for high voltage-resistant device applications.

[0038] Figure 5 This is a surface morphology diagram of the gallium oxide epitaxial wafer provided in Comparative Example 3 of the present invention. Figure 5 It can be seen that the epitaxial layer thickness of the gallium oxide epitaxial wafer prepared in Comparative Example 3 is 6 μm, but the epitaxial film quality is very poor, with many grain boundaries, a rough surface, and disordered arrangement, making it impossible to obtain a nanoscale flat surface and a high-thickness epitaxial wafer. This result proves that only the method provided by this invention can produce a nanoscale surface and a high-thickness gallium oxide epitaxial wafer.

[0039] The gallium oxide epitaxial wafer provided in Example 1 of this invention was used to prepare an SBD vertical power device using conventional methods in the art. Ti / Au was deposited on the entire back side of the gallium oxide epitaxial wafer to form an ohmic contact, and Ni / Au was deposited on the epitaxial layer to form a Schottky contact. The size of the SBD vertical power device was 200μm×200μm, and the IV characteristics of the SBD device were measured at room temperature.

[0040] Figures 6-7 To obtain the current-voltage (IV) characteristic curves of the SBD vertical power devices fabricated using the gallium oxide epitaxial wafer provided in Example 1 of this invention, five fabricated devices were selected and denoted as L1 to L5, respectively. Figures 6-7It is known that the SBD vertical power device fabricated using the gallium oxide epitaxial wafer provided by this invention has a reverse withstand voltage of 1000V and exhibits excellent high voltage withstand performance.

[0041] Embodiments 2-3 and Embodiment 1 of the present invention can achieve similar technical effects.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a gallium oxide epitaxial wafer, characterized in that, Includes the following steps: S1. Place the (011) surface gallium oxide substrate in the reaction chamber, introduce a carrier gas with a first preset flow rate, set the pressure in the reaction chamber to a first preset pressure, heat the source region of the reaction chamber to a first preset temperature, heat the growth region to a second preset temperature, and introduce oxygen with a second preset flow rate, chlorine with a third preset flow rate and hydrogen with a fourth preset flow rate for the first growth. S2. Introduce oxygen at a fifth preset flow rate and hydrogen chloride at a sixth preset flow rate to perform a second growth on the gallium oxide substrate grown in the first growth, to obtain a gallium oxide epitaxial wafer; In S1, the flow rate ratio of oxygen to chlorine is (2~3):1; In S2, the fifth preset flow rate is 200~400 sccm, and the flow rate ratio of oxygen to hydrogen chloride is (5~20):

1.

2. The method for preparing gallium oxide epitaxial wafers as described in claim 1, characterized in that, In S1, the first preset flow rate is 6000~8000 sccm; In S1, the first preset pressure is 150~250mbar.

3. The method for preparing gallium oxide epitaxial wafers as described in claim 1, characterized in that, In S1, the first preset temperature is 850~900℃; In S1, the second preset temperature is 1000~1050℃.

4. The method for preparing gallium oxide epitaxial wafers as described in claim 1, characterized in that, In S1, the second preset flow rate is 20~60 sccm.

5. The method for preparing gallium oxide epitaxial wafers as described in claim 1, characterized in that, In S1, the third preset flow rate is 10~20 sccm.

6. The method for preparing gallium oxide epitaxial wafers as described in claim 1 or 5, characterized in that, In S1, the flow rate ratio of chlorine to hydrogen is (4~20):

1.

7. The method for preparing gallium oxide epitaxial wafers as described in claim 1, characterized in that, In S1, the time for the first growth is 1 to 2 hours.

8. The method for preparing gallium oxide epitaxial wafers as described in claim 1, characterized in that, In S2, the sixth preset flow rate is 20~40 sccm.

9. The method for preparing gallium oxide epitaxial wafers as described in claim 1, characterized in that, In S2, the second growth period is 2-5 hours.

10. A gallium oxide epitaxial wafer, characterized in that, It is prepared by the method for preparing gallium oxide epitaxial wafer according to any one of claims 1 to 9.

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