Epitaxial growth methods of gallium oxide

Abstract

This invention discloses a method for epitaxial growth of gallium oxide, comprising: setting an oxygen ionization device in a reaction chamber and controlling the output power of the oxygen ionization device to be not less than 100 watts to grow gallium oxide on a gallium oxide substrate; controlling the temperature in the reaction chamber to a first temperature not exceeding 1000°C, the pressure to a first pressure not exceeding 200 mbar, controlling the oxygen source flow rate to be not more than 300 mL / min, and controlling the first molar flow ratio of oxygen to gallium to be not more than 30; growing a first gallium oxide layer on the gallium oxide substrate at a growth rate of not less than 2 μm / h; controlling the temperature in the reaction chamber to decrease, maintaining or reducing the oxygen source flow rate, and reducing the gallium source flow rate to control the second molar flow ratio of oxygen to gallium to be increased to not less than 50; growing a second gallium oxide layer on the first gallium oxide layer at a growth rate of not more than 1 μm / h; repeating the growth of the first and second gallium oxide layers until the grown gallium oxide layer reaches a predetermined thickness, which is beneficial for obtaining a high-quality gallium oxide epitaxial wafer with high electron mobility.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material preparation technology, specifically to an epitaxial growth method for gallium oxide. Background Technology

[0002] Gallium oxide (GaO) is a direct wide-bandgap semiconductor material with a large bandgap (4.2 eV ~ 4.9 eV), a breakdown field strength second only to diamond, good thermal and chemical stability, and very high transmittance (>80%) in the visible and ultraviolet regions. Based on these excellent properties, GaO materials have broad application prospects in solar-blind ultraviolet detection and high-power devices.

[0003] Currently, epitaxial growth equipment for gallium oxide (GaO) is typically vapor phase epitaxy (VPE). This equipment utilizes gallium-containing organometallic compounds and oxygen-containing gases as source materials, controlling the temperature and pressure within the equipment to perform epitaxial growth on a substrate. For homoepitaxial growth of GaO, compared to heteroepitaxial growth, the problem of a large difference in thermal expansion coefficients between the hetero substrate and the GaO material is not present, making it relatively easier.

[0004] Nevertheless, oxygen-containing gases, such as oxygen, have low decomposition efficiency. Even with increased temperatures above 700°C and increased flow rates, insufficient decomposition still occurs, affecting the growth rate of homoepitaxial gallium oxide. It can also lead to a shortage of active oxygen atoms participating in the reaction to form gallium oxide material, resulting in numerous material defects and low electron mobility. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an epitaxial growth method for gallium oxide to improve the growth quality of gallium oxide layers.

[0006] To achieve the above and other related objectives, the present invention provides a method for epitaxial growth of gallium oxide, comprising:

[0007] S0: Provides a reaction chamber and an oxygen ionization device. The oxygen ionization device is located on the oxygen source injection path outside the reaction chamber so that the oxygen source enters the reaction chamber after being acted upon by the oxygen ionization device.

[0008] S1: Place the gallium oxide substrate in the reaction chamber and control the output power of the oxygen ionization device to be no less than 100 watts;

[0009] S2: Control the temperature in the reaction chamber to a first temperature not exceeding 1000℃ and the pressure to a first pressure not exceeding 200mbar, introduce an oxygen source and a gallium source into the reaction chamber, control the oxygen source flow rate not exceeding 300mL / min, and control the first molar flow ratio of oxygen and gallium not exceeding 30, so as to grow a first gallium oxide layer on the gallium oxide substrate at a growth rate of not less than 2μm / h.

[0010] S3: Control the temperature drop in the reaction chamber, maintain or reduce the oxygen source flow rate, and reduce the gallium source flow rate to control the second molar flow ratio of oxygen and gallium to increase and not be lower than 50, and grow a second gallium oxide layer on the first gallium oxide layer at a growth rate not exceeding 1 μm / h.

[0011] S4: Repeat steps S2 and S3 until the gallium oxide layer grown reaches the predetermined thickness.

[0012] Optionally, in step S2, the first temperature is 800℃ ~ 1000℃ and the first pressure is 20 mbar ~ 100 mbar.

[0013] Optionally, the first molar flow ratio is 10 to 30.

[0014] Optionally, in step S3:

[0015] The second temperature in the reaction chamber is controlled at 500℃~900℃, and the second pressure is controlled at 10 mbar~200 mbar.

[0016] Optionally, the second molar flow ratio is 50 to 100.

[0017] Optionally, in step S2, the oxygen source flow rate is not less than 100 mL / min, and the gallium source flow rate is 100 mL / min ~ 500 mL / min.

[0018] Optionally, in step S3, the oxygen source flow rate is 60 mL / min ~ 120 mL / min, and the gallium source flow rate is 15 mL / min ~ 30 mL / min.

[0019] Optionally, after step S4 is completed, the following steps may also be performed:

[0020] S5: Control the temperature in the reaction chamber to rise to a third temperature of not less than 1000°C, increase the flow rates of the oxygen source and gallium source, and grow a third gallium oxide layer on the gallium oxide layer obtained in step S4 at a growth rate of not less than 20 μm / h.

[0021] Optionally, in step S5:

[0022] The third temperature is controlled at 1000℃~1200℃, the third pressure in the reaction chamber is 10 mbar~100 mbar, and the third molar flow ratio of oxygen to gallium is 10~30.

[0023] Optionally, the gallium source flow rate in step S5 is 600 mL / min ~ 1500 mL / min, and the oxygen source flow rate is 400 mL / min ~ 600 mL / min.

[0024] Optionally, the output power of the oxygen ionization device is controlled to be 100 watts to 500 watts, and the pressure of the oxygen source ionization channel in the oxygen ionization device is equivalent to the pressure in the reaction chamber.

[0025] Optionally, the reaction chamber is an MOCVD reaction chamber and is equipped with a gas injection device. The gallium source enters the reaction chamber through the gas injection device at a controlled flow rate, and the oxygen source flows through the oxygen ionization device and then enters the reaction chamber through the gas injection device at a controlled flow rate. The gas ejection end face of the gas injection device in the reaction chamber is arranged opposite to the base located in the reaction chamber, and the gallium oxide substrate is supported on the support surface.

[0026] Optionally, the oxygen ionization device is located above the gas injection device, and the distance h between the gas output end of the oxygen ionization device and the oxygen source injection port of the gas injection device does not exceed 10 cm; the distance between the gas ejection end face of the gas injection device and the bearing surface of the base does not exceed 10 cm.

[0027] Optionally, the oxygen source includes an oxygen-containing gas, and the gallium source includes a mixture of a non-reactive carrier gas and a gallium-organic metal compound.

[0028] Compared with the prior art, the gallium oxide epitaxial growth method of the present invention has at least the following beneficial effects:

[0029] An oxygen ionization device is installed on the oxygen source injection path outside the reaction chamber to ionize the oxygen source before it enters the reaction chamber, thereby increasing the concentration of reactive oxygen species.

[0030] During the growth of the first gallium oxide layer, the temperature in the reaction chamber is controlled to be no more than 1000°C, the pressure is controlled to be no more than 200 mbar, an oxygen source and a gallium source are introduced into the reaction chamber, the oxygen source flow rate is controlled to be no more than 300 mL / min, and the first molar flow ratio of oxygen to gallium is controlled to be no more than 30, so as to grow the first gallium oxide layer on the gallium oxide substrate at a growth rate of no less than 2 μm / h.

[0031] During the growth of the second gallium oxide layer, the temperature in the reaction chamber is controlled to decrease, the oxygen source flow rate is maintained or reduced, and the gallium source flow rate is reduced to control the second molar flow ratio of oxygen and gallium to increase and not be lower than 50, and the second gallium oxide layer is grown on the first gallium oxide layer at a growth rate not exceeding 1 μm / h.

[0032] By growing the first gallium oxide layer, impurities and defects on the gallium oxide substrate can be quickly removed and the defects can be quickly buried. By growing the second gallium oxide layer, the surface reconstruction of the Ga2O3 material can be better realized, improving the surface roughness and material quality. By repeatedly growing the first gallium oxide layer and the second gallium oxide layer, the point defects brought by the gallium oxide substrate can be buried to achieve better surface reconstruction and realize the growth of high-quality gallium oxide material layers. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the steps of the gallium oxide epitaxial growth method in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the epitaxial growth equipment in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the gallium nitride epitaxial structure in an embodiment of the present invention;

[0036] Figure 4 This is a longitudinal cross-sectional schematic diagram of the oxygen ionization device in an embodiment of the present invention;

[0037] Figure 5 This is a schematic cross-sectional view of the oxygen ionization device in an embodiment of the present invention.

[0038] Illustration of reference numerals in the attached diagram:

[0039] 100. Gallium oxide substrate; 201. First gallium oxide layer; 202. Second gallium oxide layer; 203. Third gallium oxide layer.

[0040] 10. Reaction chamber; 11. Exhaust port; 12. Oxygen source injection pipeline; 121. First injection pipeline; 122. Second injection pipeline; 13. Gallium source injection pipeline; 14. Oxygen ionization device; 141. Protective layer; 142. External electrode; 143. Dielectric material layer; 144. Oxygen source ionization channel; 145. Internal electrode; 146. Cooling water channel; 15. Rotation device; 16. Base; 17. Heating device; 18. Isolation device; 19. Purge pipeline; 20. Pressure gauge; 21. Gas injection device; 211. First chamber; 212. Second chamber; 213. Gas ejection end face. Detailed Implementation

[0041] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0042] It should be understood that the illustrations provided in the embodiments of this invention are merely schematic representations of the basic concept of the invention. Although the illustrations only show components relevant to the invention and are not drawn according to the actual number, shape, and size of components in implementation, the shape, quantity, and proportion of each component can be arbitrarily changed in actual implementation, and the component layout may also be more complex. The structures, proportions, sizes, etc., shown in the accompanying drawings are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that the invention can produce, should still fall within the scope of the technical content disclosed in this application.

[0043] In this embodiment of the invention, the term "between" used to define the numerical range includes the endpoint values ​​of the numerical range.

[0044] Example 1

[0045] This embodiment provides a gallium oxide epitaxial growth method, referring to... Figure 1 The epitaxial growth method for gallium oxide includes:

[0046] S0: Provides a reaction chamber and an oxygen ionization device. The oxygen ionization device is located on the oxygen source injection path outside the reaction chamber so that the oxygen source enters the reaction chamber after being acted upon by the oxygen ionization device.

[0047] S1: Place the gallium oxide substrate in the reaction chamber and control the output power of the oxygen ionization device to be no less than 100 watts;

[0048] S2: Control the temperature in the reaction chamber to a first temperature not exceeding 1000℃ and the pressure to a first pressure not exceeding 200mbar, introduce the oxygen source and gallium source into the reaction chamber, control the flow rate of the oxygen source to not exceed 300mL / min, and control the first molar flow ratio of oxygen and gallium to not exceed 30, so as to grow a first gallium oxide layer on the gallium oxide substrate at a growth rate of not less than 2μm / h.

[0049] S3: Control the temperature drop in the reaction chamber, maintain or reduce the oxygen source flow rate, and reduce the gallium source flow rate to control the second molar flow ratio of oxygen and gallium to increase and not be lower than 50, and grow a second gallium oxide layer on the first gallium oxide layer at a growth rate not exceeding 1 μm / h.

[0050] S4: Repeat steps S2 and S3 until the gallium oxide layer grown reaches the predetermined thickness.

[0051] In step S0 of some embodiments, reference is made to Figure 2 The system provides a reaction chamber 10 and an oxygen ionization device 14. The oxygen ionization device 14 is installed on the oxygen source injection line 12 outside the reaction chamber 10. By adding the oxygen ionization device 14 to the oxygen source injection line 12 of the reaction chamber 10 to promote oxygen decomposition, the oxygen decomposition efficiency can be improved, especially avoiding the problem of insufficient oxygen decomposition at high temperatures. This avoids the quality problem of gallium oxide film caused by insufficient O / Ga ratio, and also solves the problem of slow growth rate of Ga2O3 material, thus improving the growth efficiency of Ga2O3.

[0052] In existing technologies, PECVD equipment can also achieve oxygen plasmaization. However, in PECVD equipment, the voltage applied to the internal space of the reaction chamber affects not only the oxygen source but also the gallium source. This means that after the gallium source enters the reaction chamber 10, its decomposition is affected by both heat and ionization, making the decomposition mechanism complex and its controllability low. Furthermore, since the substrate is located in the plasma region, high-energy ions and electrons will continuously attack the thin film already formed on the substrate. This reaction space atmosphere is not conducive to high-quality gallium oxide epitaxial growth.

[0053] In this embodiment, the reaction chamber 10 is an MOCVD reaction chamber. This embodiment combines the oxygen ionization device 14 with the MOCVD reaction chamber: the oxygen ionization device 14 is positioned upstream of the gas injection device 21, avoiding the need to place the substrate within the plasma region, which is beneficial for high-quality gallium oxide epitaxial growth; the oxygen source undergoes plasma activation before entering the gas injection device 21, and the activation level of the oxygen source can be easily controlled by adjusting the output power of the oxygen ionization device 14 (i.e., the plasma power acting on the oxygen source) and the flow rate of the oxygen source into the oxygen ionization device 14; on the other hand, the gallium source enters the reaction chamber 10 directly via the gas injection device 21 and is activated through thermal decomposition, and the activation level of the gallium source can also be easily controlled by adjusting the gallium source flow rate and the temperature within the reaction chamber 10. More importantly, the diffusion of both the ionized oxygen source and the entering gallium source within the reaction chamber 10 follows the principles of MOCVD control, which is beneficial for achieving epitaxial growth with better film uniformity compared to PECVD.

[0054] In this embodiment, the pressure inside the oxygen ionization device 14 is controlled to be consistent with the pressure inside the reaction chamber 10. Oxygen is supplied to the oxygen ionization device 14 at a controlled flow rate by its supply device, and then enters the reaction chamber 10 after ionization. Specifically, refer to... Figure 2 and Figure 3 The oxygen source injection pipeline 12 includes a first injection pipeline 121 and a second injection pipeline 122. The oxygen source enters the oxygen ionization device 14 from the first injection pipeline 121, and the oxygen source after ionization is ejected from the second injection pipeline 122 and enters the gas injection device 21.

[0055] In this embodiment, refer to Figure 3 The gas injection device 21 includes a first chamber 211 and a second chamber 212 that are not interconnected. Both the first chamber 211 and the second chamber 212 are connected to the outside (i.e., the space inside the reaction chamber 10), so that the gallium source and the oxygen source do not undergo premixing or pre-reaction upon entering the gas injection device 21. The gallium source enters the gallium source injection pipe 13, which is connected to the second chamber 212, allowing the gallium source to enter the interior of the reaction chamber 10 via the second chamber 212. The ionized oxygen source enters the first chamber 211 via the second injection pipe 122, and then enters the interior of the reaction chamber 10 from the first chamber 211.

[0056] In this embodiment, refer to Figure 2 and Figure 3 The reaction chamber 10 is provided with a gas injection device 21 and a base 16. The gas ejection end face 213 of the gas injection device 21 is positioned opposite to the base 16 located in the reaction chamber 10. The distance between the gas ejection end face 213 of the gas injection device 21 and the bearing surface of the base 16 does not exceed 10 cm. This is to prevent the loss of activity due to the mutual coupling between different types of active oxygen after ionization caused by the excessive distance. This ensures that the active oxygen decomposed by ionization can participate in the gas phase reaction of O and Ga near the substrate surface in a timely manner and be deposited on the substrate.

[0057] In some embodiments, the distance between the gas ejection end face 213 and the bearing surface of the base 16 does not exceed 7 cm.

[0058] In some embodiments, the distance between the gas ejection end face 213 and the bearing surface of the base 16 is between 1 cm and 5 cm.

[0059] In some embodiments, reference is made to Figure 3The oxygen ionization device 14 is positioned above the gas injection device 21. The distance h between the gas output end of the oxygen ionization device 14 and the oxygen source injection port of the gas injection device 21 does not exceed 10 cm, ensuring that the decomposed oxygen can be promptly applied to the reaction of O and Ga in the reaction chamber 10. In some embodiments, the support surface of this embodiment has several recesses for placing the gallium oxide substrate. The recesses are arranged around the central region of the substrate carrier, exposing each recess to the environment of the reaction space.

[0060] In this embodiment, the gallium oxide epitaxial growth method is performed using an MOCVD epitaxial growth device. Specifically, refer to... Figure 2 The epitaxial growth apparatus includes a reaction chamber 10, within which a base 16, a heating device 17, and an isolation device 18 are disposed. The heating device 17 is located at the bottom of the base 16, and the isolation device 18 surrounds the edge of the base 16, enclosing the area below the base 16 to form an isolation space, thereby isolating the heating device 17 located at the bottom of the base 16. Optionally, a gap exists between the isolation device 18 and the base 16 to make the isolation space non-sealed. In this case, a purging device is also provided outside the reaction chamber 10, and this purging device communicates with the isolation space inside the reaction chamber 10. During epitaxial growth, a chemically inert purge gas can be introduced into the isolation space via a purge device. Driven by gas pressure, the purge gas enters the reaction chamber 10 through the isolation gap between the isolation device 18 and the base 16. This maintains a slightly positive pressure between the isolation space and the reaction chamber 10, preventing gas from the reaction chamber 10 from entering the isolation space and corroding the heating device 17, thereby improving the reliability and service life of the epitaxial growth equipment. In some specific embodiments, the isolation device 18 is made of graphite or molybdenum.

[0061] In step S1 of some embodiments, referring to Figure 2 and Figure 4 The gallium oxide substrate 100 is placed on the recess of the base 16 in the reaction chamber 10, and the output power applied to the oxygen ionization device 14 is controlled to be no less than 100 watts.

[0062] In some embodiments, the output power is controlled to be 100 watts to 500 watts.

[0063] In some embodiments, the pressure in the oxygen supply channel of the oxygen ionization device 14 is controlled to be consistent with the pressure inside the reaction chamber. That is, during the pressure adjustment process in each step, the pressure in the oxygen supply channel of the oxygen ionization device 14 is simultaneously adjusted to be consistent with the pressure inside the reaction chamber.

[0064] In some embodiments, the ionization of the oxygen ionization device is stopped during the temperature and / or pressure adjustment between steps to reduce energy consumption.

[0065] In some embodiments, the rotating device 15 is driven to rotate so that the base 16 in the reaction chamber 10 rotates about the central axis of the rotating device 15, while the homogeneous substrate on the base 16 also rotates synchronously.

[0066] In some embodiments, the rotational speed of the rotating device 15 is controlled to not exceed 120 rpm.

[0067] In step S2 of some embodiments: Refer to Figure 2 and Figure 4 After placing the gallium oxide substrate 100, a first gallium oxide layer 201 is formed on the gallium oxide substrate 100. Specifically, the temperature inside the reaction chamber 10 is controlled to be a first temperature not exceeding 1000°C, and the pressure is controlled to be a first pressure not exceeding 200 mbar. An oxygen source and a gallium source are introduced into the reaction chamber 10, the oxygen source flow rate is controlled to be not exceeding 300 mL / min, and the first molar flow ratio of oxygen to gallium is controlled to be not exceeding 30, so as to grow the first gallium oxide layer 201 on the gallium oxide substrate 100 at a growth rate of not less than 2 μm / h.

[0068] Optionally, the first temperature is between 800℃ and 1000℃.

[0069] Optionally, the first pressure is between 20 mbar and 100 mbar. The first molar flow ratio is between 10 and 30, for example, 12.5, 20, or 25.

[0070] In step S2, growing the first gallium oxide layer 201 at a first temperature and a first pressure is beneficial for quickly removing impurities and defects on the gallium oxide substrate and rapidly burying the defects to prevent them from extending into subsequent epitaxial layers. This layer growth requires a higher temperature and a lower molar ratio of oxygen to gallium (i.e., the O / Ga ratio) to ensure high-quality epitaxial growth. Since the oxygen source enters the reaction chamber 10 after ionization by the oxygen ionization device 14, the amount of effective active oxygen participating in the reaction is large at this temperature and pressure. Controlling the O / Ga ratio to no more than 30 avoids the formation of significant point defects in the gallium oxide layer due to excessive effective active oxygen, which could affect the background concentration (i.e., intrinsic carrier concentration) and electron mobility.

[0071] Optionally, the flow rate of the oxygen source is not less than 100 mL / min, and the flow rate of the gallium source is between 100 mL / min and 500 mL / min, for example, it can be 120 mL / min, 150 mL / min, 240 mL / min, 480 mL / min, etc.

[0072] In this embodiment, the growth rate of the first gallium oxide layer 201 is 4 μm / h ~ 10 μm / h, and the thickness of the first gallium oxide layer 201 is between 100 nm and 500 nm.

[0073] In this embodiment, the oxygen source is oxygen gas, and the gallium source is a mixture of a non-reactive carrier gas and a gallium organometallic compound. The non-reactive carrier gas can be at least one of argon, nitrogen, and hydrogen chloride, or other suitable carrier gases.

[0074] In step S3 of some embodiments, reference is made to Figure 2 and Figure 4 After the formation of the first gallium oxide layer 201, the temperature in the reaction chamber 10 is controlled to decrease, the oxygen source flow rate is maintained or reduced, and the gallium source flow rate is reduced to control the second molar flow ratio of oxygen and gallium to increase and not be lower than 50, and the second gallium oxide layer 202 is grown on the first gallium oxide layer 201 at a growth rate not exceeding 1 μm / h.

[0075] Optionally, the temperature difference between the second temperature and the first temperature shall not exceed 500 °C, and the pressure difference between the second pressure and the first pressure shall not exceed 30 mbar.

[0076] Optionally, the second temperature is 500℃~900℃. The second pressure is 10 mbar~200 mbar.

[0077] Optionally, the second molar flow ratio is between 50 and 100. Thus, the second gallium oxide layer 202 is grown under conditions of a lower O / Ga ratio, higher temperature, and lower pressure. Compared to the growth conditions for the first gallium oxide layer 201, this appropriately reduces the growth temperature and growth rate, better achieving surface reconstruction and helping to reduce surface roughness, thereby improving background concentration and electron mobility. Simultaneously, the O / Ga ratio is also controlled within a low range, avoiding the formation of significant point defects in the gallium oxide layer due to excessive effective active oxygen, which could negatively impact background concentration and electron mobility.

[0078] Optionally, the reduction in oxygen source flow rate shall not exceed 180 mL / min, for example, the oxygen source flow rate shall not exceed 120 mL / min, such as 60 mL / min to 120 mL / min. The reduction in gallium source flow rate shall not be less than 90 mL / min, for example, the difference in gallium source flow rate reduction shall be between 90 mL / min and 480 mL / min. The gallium source flow rate shall not exceed 30 mL / min and shall not be less than 15 mL / min.

[0079] Optionally, the growth rate of the second gallium oxide layer 202 is lower than the growth rate of the first gallium oxide layer 201, and the difference between the growth rates of the first gallium oxide layer 201 and the second gallium oxide layer 202 does not exceed 10 μm / h. Optionally, the growth rate of the second gallium oxide layer 202 is 0.2 μm / h to 1 μm / h.

[0080] Optionally, the thickness of the second gallium oxide layer 202 is less than the thickness of the first gallium oxide layer 201, and the difference between the thickness of the first gallium oxide layer 201 and the thickness of the second gallium oxide layer 202 does not exceed 400 nm. The thickness of the second gallium oxide layer 202 is between 100 nm and 200 nm.

[0081] In S4 of some embodiments, reference is made to Figure 4 The first gallium oxide layer 201 and the second gallium oxide layer 202 are repeatedly grown on the second gallium oxide layer 202 obtained in step S3 according to the above steps S2~S3, and the number of cycles is 2~50 times. The repeatedly grown first gallium oxide layer 201 and second gallium oxide layer 202 can cover the point defects brought by the gallium oxide substrate and achieve better surface reconstruction, thereby improving the surface quality and the crystal quality of the material.

[0082] In an optional embodiment, after step S4 is completed, step S5 is further included: controlling the temperature in the reaction chamber to rise to a third temperature not lower than 1000°C, increasing the flow rates of the oxygen source and gallium source, so as to grow a third gallium oxide layer on the gallium oxide layer obtained in step S4 at a growth rate not lower than 20 μm / h.

[0083] Reference Figure 2 and Figure 4 In step S4, a third gallium oxide layer 203 is grown on the last second gallium oxide layer 202. Specifically, the third temperature is 1000℃~1200℃, the third pressure in the reaction chamber is 10 mbar~100 mbar, and the third molar flow rate ratio of the oxygen source to the gallium source is 10~30. The temperature difference between the third temperature and the second temperature does not exceed 600℃, the pressure difference between the third pressure and the second pressure is 0 mbar~100 mbar, and the decrease in the third molar flow rate ratio does not exceed 90%, for example, 25~90. Therefore, the growth of the third gallium oxide layer 203 increases the growth temperature and reduces the growth pressure compared to the second gallium oxide layer 202, ensuring high-quality growth of the final material layer.

[0084] Optionally, the gallium source flow rate decrease is between 600 mL / min and 1500 mL / min. The gallium source flow rate is not less than 600 mL / min. The oxygen source flow rate increase is between 360 mL / min and 540 mL / min. The oxygen source flow rate is not less than 480 mL / min, for example, between 480 mL / min and 600 mL / min.

[0085] Optionally, the growth rate of the third gallium oxide layer 203 is greater than the growth rate of the first gallium oxide layer 201, and the difference between the growth rate of the third gallium oxide layer 203 and the growth rate of the first gallium oxide layer 201 does not exceed 40 μm / h and is not less than 19 μm / h. Optionally, the growth rate of the third gallium oxide layer 203 is 20 μm / h to 40 μm / h.

[0086] Optionally, the thickness of the third gallium oxide layer 203 is greater than the thickness of the first gallium oxide layer 201, and the difference between the thickness of the third gallium oxide layer 203 and the thickness of the first gallium oxide layer 201 is not less than 9900 nm. Optionally, the thickness of the third gallium oxide layer 203 is between 10000 nm and 50000 nm.

[0087] The gallium oxide epitaxial growth method in this embodiment benefits from the improved oxygen source decomposition efficiency assisted by oxygen ionization, thereby ensuring an effective supply of active oxygen in the reaction and achieving high growth rate and high epitaxial quality.

[0088] Example 2

[0089] This embodiment provides an epitaxial growth apparatus for performing the gallium oxide epitaxial growth method in Embodiment 1.

[0090] Specifically, refer to Figure 2 The epitaxial growth apparatus includes a reaction chamber 10, a base 16, a heating device 17, an oxygen source injection device, and an oxygen ionization device 14. The base 16 is disposed inside the reaction chamber 10 and is used to support the substrate for gallium oxide growth. The heating device 17 is disposed at the bottom of the base 16 and is used to control the reaction temperature inside the reaction chamber 10. The oxygen source injection device is disposed outside the reaction chamber 10 and is connected to the reaction chamber 10 via an oxygen source injection pipe 12, used to inject oxygen into the reaction chamber 10. The oxygen ionization device 14 is disposed outside the reaction chamber 10 and is disposed on the oxygen source injection pipe 12 connecting the oxygen source injection device and the reaction chamber 10. The oxygen ionization device 14 is used to ionize the oxygen introduced into the reaction chamber 10, promoting oxygen decomposition efficiency. Optionally, the distance between the output end of the oxygen ionization device 14 and the oxygen source injection port of the reaction chamber 10 does not exceed 10 cm to ensure that the decomposed oxygen can be promptly applied to the reaction of O and Ga in the reaction chamber 10. Optionally, the epitaxial growth apparatus further includes a gallium source injection device, which injects gallium source into the reaction chamber 10 through a gallium source injection pipe 13. Optionally, a rotating device 15 is also provided inside the reaction chamber 10, which supports the base 16 and drives the base 16 to rotate during the reaction. Optionally, an exhaust port 11 is also provided at the bottom of the reaction chamber 10 for exhausting the reaction chamber.

[0091] Optionally, refer to Figure 2The epitaxial growth apparatus also includes an isolation device 18, which is disposed below the base 16 and surrounds the edge of the base 16 to enclose the area below the base 16 to form an isolation space, within which the heating device 17 is located. Thus, the isolation device 18 can isolate the heating device 17 at the bottom of the base 16, preventing contamination or corrosion from the gas inside the reaction chamber 10.

[0092] Optionally, refer to Figure 2 An isolation device 18 and a base 16 are spaced apart to ensure the isolation space is not sealed. The reaction chamber 10 also includes a purging device connected to the isolation space within the reaction chamber 10 via a purging pipe 19. During epitaxial growth, gas can be introduced into the isolation space through the purging device to maintain a slightly positive pressure compared to the reaction chamber 10. This prevents gas from entering the isolation space and damaging the heating device 17 located within it, thus improving the reliability and lifespan of the epitaxial growth equipment. Optionally, a pressure gauge 20 is also provided in the reaction chamber 10 to monitor the pressure within the chamber.

[0093] The oxygen ionization device 14 can be implemented in a manner that is necessary to achieve the plasmaization of an oxygen source, such as oxygen, for example, a plasma generator.

[0094] In some embodiments, reference is made to Figure 2 and Figure 5 The oxygen ionization device 14 has a cylindrical core component for plasma generation. The central core is a cooling water channel 146. Surrounding the cooling water channel 146, from the inside out, are an inner electrode 145, an oxygen source ionization channel 144, a dielectric material layer 143, an outer electrode 142, and a protective layer 141. An insulating layer exists between the inner electrode 145 and the cooling water. The oxygen source ionization channel 144, adjacent to the inner electrode 145, is a hollow layer. The dielectric material layer 143 surrounding the oxygen source ionization channel 144 is made of ceramic. The outer electrode 142, adjacent to the dielectric material layer 143, is covered by a protective layer 141 made of insulating material, which also serves a heat dissipation function. Optionally, both the inner electrode 145 and the outer electrode 142 are made of copper. Oxygen enters the oxygen source ionization channel 144 and is ionized under the action of the inner and outer electrodes. This oxygen ionization device 14 is a common structure in the prior art and will not be described in detail here.

[0095] Optionally, the epitaxial growth apparatus also includes a gas injection device 21, as shown in the reference. Figure 3 The structure of the gas injection device 21 is the same as that in Embodiment 1, and will not be described again here.

[0096] The present invention will now be described in detail with reference to specific embodiments. The oxygen ionization device used in each specific embodiment is an FG5001 plasma generator. The growth rate is calculated using the MOCVD online monitoring system viperRTC-LSS by measuring the change in reflectivity of light on the surface of the grown film. This system is specifically installed on top of the gas injection device 21, and its installation and operation are conventional techniques in the art. Background concentration and electron mobility are measured using a Nanometrics Hall effect meter.

[0097] The present invention will now be described in detail with reference to specific embodiments.

[0098] Example 1

[0099] This embodiment provides a homoepitaxial growth method for gallium oxide using an MOCVD epitaxial growth apparatus. The specific structure of the epitaxial growth apparatus is as follows: Figure 2 and Figure 3 As shown, the grown gallium oxide epitaxial structure is as follows: Figure 4 As shown.

[0100] Six recesses are circumferentially arranged on the base 16 within the reaction chamber, each recess configured to support a 2-inch substrate. The base 16 is a graphite disk with a top surface diameter of 150 mm. The distance from the gas ejection end face 213 of the gas injection device 21 to the support surface of the base 16 is 1 cm. The gallium source is a mixture of trimethylgallium and nitrogen as the carrier gas, and the oxygen source is O2. An oxygen ionization device 14 is positioned h = 5 cm above the top surface of the gas injection device 21 in the MOCVD reaction chamber 10 on the oxygen source injection line 12. In this embodiment, the oxygen ionization device 14 is a plasma generator.

[0101] Epitaxial growth methods for gallium oxide include:

[0102] S1: Place each gallium oxide substrate in each cavity, control the application of 30 kV AC current to the inner and outer electrodes of the oxygen ionization device 14, and control the pressure in the oxygen source ionization channel to be 20 mbar, so that the output power of the oxygen ionization device 14 is controlled to be 100 watts.

[0103] S2: Control the temperature of reaction chamber 10 to rise to 800℃, the pressure of reaction chamber 10 to 20 mBar, control the rotation speed of rotating device 15 to 30 rpm, introduce trimethylgallium and nitrogen as gallium source mixed gas into gallium source injection pipe 13 and control the flow rate to 120 mL / min, introduce oxygen as oxygen source into first injection pipe 121 and control the flow rate to 120 mL / min, wherein the molar flow ratio of oxygen to gallium, i.e. O / Ga ratio, is 25, until the growth thickness of the first gallium oxide layer 201 is 100 nm, and the growth rate of the first gallium oxide layer 201 is 4 μm / h;

[0104] S3: Stop the supply of gallium source, maintain the rotation control of base 16, stop the ionization of plasma generator and supply oxygen through first injection pipe 121 until the control temperature drops to 600 ℃, adjust the growth pressure and the pressure in the oxygen source ionization channel to 10 mBar, control the output power of plasma generator to be consistent with step S1, maintain the rotation control of base 16 at 30 rpm, introduce trimethylgallium and nitrogen as a mixed gas of gallium source into gallium source injection pipe 13 and control the flow rate to 30 mL / min, adjust the oxygen flow rate into first injection pipe 121 to 120 mL / min, control the O / Ga ratio to 100, until the growth thickness of the second gallium oxide layer 202 is 200 nm and the growth rate of the second gallium oxide layer 202 is 1 μm / h;

[0105] S4: Repeat steps S2 and S3 to execute the loop 40 times;

[0106] S5: Stop the supply of gallium source, maintain the rotation control of base 16, stop the ionization of plasma generator and supply oxygen through first injection pipe 121 until the control temperature is raised to 1000 ℃. After adjusting the growth pressure and the pressure in the oxygen source ionization channel to 10 mBar, control the output power of plasma generator to be consistent with step S1. Maintain the rotation control of base 16 at 30 rpm. Introduce trimethylgallium and nitrogen as a mixed gas for gallium source into gallium source injection pipe 13 and control the flow rate to 600 mL / min. Introduce oxygen into first injection pipe 121 and control the flow rate to 480 mL / min. The O / Ga ratio is 20 until the growth thickness of the third gallium oxide layer 203 is 10000 nm and the growth rate of the third gallium oxide layer 203 is 20 μm / h.

[0107] The epitaxial wafer obtained through the above steps was cut into 1 cm × 1 cm square test samples, and Hall effect measurements were performed. The electron mobility of the test sample was found to be 150 cm⁻¹. 2 The background concentration (i.e., intrinsic carrier concentration) is 1.3 × 10⁻⁶ (V·s). 16 cm -3 .

[0108] Example 2

[0109] This embodiment provides a homoepitaxial growth method for gallium oxide using an MOCVD epitaxial growth apparatus. The specific structure of the epitaxial growth apparatus is as follows: Figure 2 and Figure 3 As shown, the grown gallium oxide epitaxial structure is as follows: Figure 4 As shown.

[0110] The difference between this epitaxial growth apparatus and the apparatus used in Example 1 is that: 12 recesses are arranged circumferentially on the base of the reaction chamber, each recess being configured to support a 2-inch substrate. The diameter of the top surface of the base 16 is 260 mm, and the distance from the gas ejection end face 213 of the gas injection device 21 to the supporting surface of the base 16 is 2 cm.

[0111] Epitaxial growth methods for gallium oxide include:

[0112] S1: Place each gallium oxide substrate in each cavity, control the application of 30 kV AC current to the inner and outer electrodes of the oxygen ionization device 14, and control the pressure in the oxygen source ionization channel to be 50 mbar, so that the output power of the oxygen ionization device 14 is controlled to be 200 watts.

[0113] S2: Control the temperature of reaction chamber 10 to rise to 850℃, the pressure of reaction chamber 10 to 50 mBar, control the rotation speed of rotating device 15 to 50 rpm, introduce trimethylgallium and nitrogen as gallium source mixed gas into gallium source injection pipe 13 and control the flow rate to 150 mL / min, introduce oxygen as oxygen source into first injection pipe 121 and control the flow rate to 120 mL / min, wherein the molar flow ratio of oxygen to gallium, i.e. O / Ga ratio, is 20, until the growth thickness of the first gallium oxide layer 201 is 300 nm, and the growth rate of the first gallium oxide layer 201 is 4 μm / h;

[0114] S3: Stop the supply of gallium source, maintain the rotation control of base 16, stop the ionization of plasma generator and supply oxygen through first injection pipe 121 until the control temperature drops to 800 ℃, adjust the growth pressure and the pressure in the oxygen source ionization channel to 50 mBar, control the output power of plasma generator to be consistent with step S1, maintain the rotation control of base 16 at 50 rpm, introduce trimethylgallium and nitrogen as a mixed gas of gallium source into gallium source injection pipe 13 and control the flow rate to 15 mL / min, adjust the oxygen flow rate into first injection pipe 121 to 60 mL / min, control the O / Ga ratio to 100, until the growth thickness of the second gallium oxide layer 202 is 100 nm and the growth rate of the second gallium oxide layer 202 is 0.4 μm / h;

[0115] S4: Repeat steps S2 and S3 to execute the loop 30 times;

[0116] S5: Stop the supply of gallium source, maintain the rotation control of the base 16, stop the ionization of the plasma generator and supply oxygen through the first injection pipe 121 until the control temperature is raised to 1100 ℃. After adjusting the growth pressure and the pressure in the oxygen source ionization channel to 20 mBar, control the output power of the plasma generator to be consistent with step S1, maintain the rotation control of the base 16 at 50 rpm, introduce trimethylgallium and nitrogen as a mixed gas for gallium source into the gallium source injection pipe 13 and control the flow rate to 720 mL / min, introduce oxygen into the first injection pipe 121 and control the flow rate to 600 mL / min, with an O / Ga ratio of 25, until the growth thickness of the third gallium oxide layer 203 is 10000 nm and the growth rate of the third gallium oxide layer 203 is 20 μm / h.

[0117] The epitaxial wafer obtained through the above steps was cut into 1 cm × 1 cm square test samples, and Hall effect measurements were performed. The electron mobility of the test sample was found to be 160 cm⁻¹. 2 The background concentration (i.e., intrinsic carrier concentration) is 1.2 × 10⁻⁶ (V·s). 16 cm -3 .

[0118] Example 3

[0119] This embodiment provides a homoepitaxial growth method for gallium oxide using an MOCVD epitaxial growth apparatus. The specific structure of the epitaxial growth apparatus is as follows: Figure 2 and Figure 3 As shown, the grown gallium oxide epitaxial structure is as follows: Figure 4 As shown.

[0120] The difference between this epitaxial growth equipment and the equipment used in Example 1 is that:

[0121] The base of the reaction chamber has 19 recesses circumferentially arranged, each recess configured to support a 2-inch substrate. The diameter of the top surface of the base 16 is 300 mm. The distance from the gas ejection end face 213 of the gas injection device 21 to the supporting surface of the base 16 is 3 cm.

[0122] Epitaxial growth methods for gallium oxide include:

[0123] S1: Place each gallium oxide substrate in each cavity, control the application of 30 kV AC current to the inner and outer electrodes of the oxygen ionization device 14, and control the pressure in the oxygen source ionization channel to be 80 mbar, so that the output power of the oxygen ionization device 14 is controlled to be 300 watts.

[0124] S2: Control the temperature of reaction chamber 10 to rise to 900℃, the pressure of reaction chamber 10 to 80 mBar, control the rotation speed of rotating device 15 to 80 rpm, introduce trimethylgallium and nitrogen as gallium source mixed gas into gallium source injection pipe 13 and control the flow rate to 240 mL / min, introduce oxygen as oxygen source into first injection pipe 121 and control the flow rate to 240 mL / min, wherein the molar flow ratio of oxygen to gallium, i.e. O / Ga ratio, is 25, until the growth thickness of the first gallium oxide layer 201 is 200 nm, and the growth rate of the first gallium oxide layer 201 is 6 μm / h;

[0125] S3: Stop the supply of gallium source, maintain the rotation control of base 16, stop the ionization of plasma generator and supply oxygen through first injection pipe 121 until the control temperature drops to 800 ℃. After adjusting the growth pressure and the pressure in the oxygen source ionization channel to 100 mBar, control the output power of plasma generator to be consistent with step S1, maintain the rotation control of base 16 at 80 rpm, introduce trimethylgallium and nitrogen as a mixed gas of gallium source into gallium source injection pipe 13 and control the flow rate to 30 mL / min, adjust the oxygen flow rate into first injection pipe 121 to 60 mL / min, control the O / Ga ratio to 50, until the growth thickness of the second gallium oxide layer 202 is 120 nm and the growth rate of the second gallium oxide layer 202 is 0.5 μm / h;

[0126] S4: Repeat steps S2 and S3 to execute the loop 20 times;

[0127] S5: Stop the supply of gallium source, maintain the rotation control of base 16, stop the ionization of plasma generator and supply oxygen through first injection pipe 121 until the control temperature is raised to 1050 ℃. After adjusting the growth pressure and the pressure in the oxygen source ionization channel to 50 mBar, control the output power of plasma generator to be consistent with step S1, maintain the rotation control of base 16 at 80 rpm, introduce trimethylgallium and nitrogen as a mixed gas of gallium source into gallium source injection pipe 13 and control the flow rate to 1200 mL / min, introduce oxygen into first injection pipe 121 and control the flow rate to 480 mL / min, O / Ga ratio is 10, until the growth thickness of the third gallium oxide layer 203 is 20000 nm and the growth rate of the third gallium oxide layer 203 is 35 μm / h.

[0128] The epitaxial wafer obtained through the above steps was cut into 1 cm × 1 cm square test samples, and Hall effect measurements were performed. The electron mobility of the test sample was found to be 180 cm⁻¹. 2 The background concentration (i.e., intrinsic carrier concentration) is 1.1 × 10⁻⁶ (V·s). 16 cm -3.

[0129] Example 4

[0130] This embodiment provides a homoepitaxial growth method for gallium oxide using an MOCVD epitaxial growth apparatus. The specific structure of the epitaxial growth apparatus is as follows: Figure 2 and Figure 3 As shown, the grown gallium oxide epitaxial structure is as follows: Figure 4 As shown.

[0131] The difference between this epitaxial growth equipment and the equipment used in Example 1 is that:

[0132] A recess is provided circumferentially on the base of the reaction chamber, and each recess supports a 6-inch substrate. The distance from the gas ejection end face 213 of the gas injection device 21 to the bearing surface of the base 16 is 5 cm.

[0133] Epitaxial growth methods for gallium oxide include:

[0134] S1: Place each gallium oxide substrate in each cavity, control the application of 50 kV AC current to the inner and outer electrodes of the oxygen ionization device 14, and control the pressure in the oxygen source ionization channel to be 100 mbar, so that the output power of the oxygen ionization device 14 is controlled to be 500 watts.

[0135] S2: Control the temperature of reaction chamber 10 to rise to 1000℃, the pressure of reaction chamber 10 to 100 mBar, control the rotation speed of rotating device 15 to 120 rpm, introduce trimethylgallium and nitrogen as gallium source mixed gas into gallium source injection pipe 13 and control the flow rate to 480 mL / min, introduce oxygen as oxygen source into first injection pipe 121 and control the flow rate to 240 mL / min, wherein the molar flow ratio of oxygen to gallium, i.e. O / Ga ratio, is 12.5, until the growth thickness of the first gallium oxide layer 201 is 500 nm, and the growth rate of the first gallium oxide layer 201 is 10 μm / h;

[0136] S3: Stop the supply of gallium source, maintain the rotation control of base 16, stop the ionization of plasma generator and supply oxygen through first injection pipe 121 until the control temperature drops to 900 ℃, adjust the growth pressure and the pressure in the oxygen source ionization channel to 200 mBar, control the output power of plasma generator to be consistent with step S1, maintain the rotation control of base 16 at 120 rpm, introduce trimethylgallium and nitrogen as a mixed gas of gallium source into gallium source injection pipe 13 and control the flow rate to 30 mL / min, adjust the oxygen flow rate into first injection pipe 121 to 60 mL / min, control the O / Ga ratio to 50, until the growth thickness of the second gallium oxide layer 202 is 150 nm and the growth rate of the second gallium oxide layer 202 is 0.2 μm / h;

[0137] S4: Repeat steps S2 and S3 to execute the loop 50 times;

[0138] S5: Stop the supply of gallium source, maintain the rotation control of base 16, stop the ionization of plasma generator and supply oxygen through first injection pipe 121 until the control temperature is raised to 1200 ℃. After adjusting the growth pressure and the pressure in the oxygen source ionization channel to 100 mBar, control the output power of plasma generator to be consistent with step S1, maintain the rotation control of base 16 at 80 rpm, introduce trimethylgallium and nitrogen as a mixed gas of gallium source into gallium source injection pipe 13 and control the flow rate to 1500 mL / min, introduce oxygen into first injection pipe 121 and control the flow rate to 600 mL / min, O / Ga ratio is 10, until the growth thickness of the third gallium oxide layer 203 is 50000 nm and the growth rate of the third gallium oxide layer 203 is 40 μm / h.

[0139] The epitaxial wafer obtained through the above steps was cut into 1 cm × 1 cm square test samples, and Hall effect measurements were performed. The electron mobility of the test sample was found to be 200 cm⁻¹. 2 / (V·s), the background concentration (i.e., intrinsic carrier concentration) is: 1×10 16 cm -3 .

[0140] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for epitaxial growth of gallium oxide, characterized in that, Includes the following steps: S0: Provides a reaction chamber and an oxygen ionization device, wherein the oxygen ionization device is disposed on the oxygen source injection path outside the reaction chamber so that the oxygen source enters the reaction chamber after being acted upon by the oxygen ionization device, and the reaction chamber is an MOCVD reaction chamber; S1: Place the gallium oxide substrate in the reaction chamber and control the output power of the oxygen ionization device to be no less than 100 watts; S2: Control the temperature in the reaction chamber to a first temperature not exceeding 1000℃ and the pressure to a first pressure not exceeding 200mbar, introduce the oxygen source and gallium source into the reaction chamber, control the flow rate of the oxygen source to not exceed 300mL / min, and control the first molar flow ratio of oxygen and gallium to not exceed 30, so as to grow a first gallium oxide layer on the gallium oxide substrate at a growth rate of not less than 2μm / h. S3: Control the temperature in the reaction chamber to drop to a second temperature of 500°C ~ 900°C, maintain or reduce the oxygen source flow rate, and reduce the gallium source flow rate to control the second molar flow ratio of oxygen and gallium to increase and not be lower than 50, and grow a second gallium oxide layer on the first gallium oxide layer at a growth rate not exceeding 1 μm / h. S4: Repeat steps S2 and S3 until the gallium oxide layer grown reaches the predetermined thickness. S5: Control the temperature in the reaction chamber to rise to a third temperature of not less than 1000°C, and increase the flow rates of the oxygen source and the gallium source to grow a third gallium oxide layer on the gallium oxide layer obtained in step S4 at a growth rate of not less than 20 μm / h.

2. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, In step S2, the first temperature is 800℃ ~ 1000℃, and the first pressure is 20 mbar ~ 100 mbar.

3. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, The first molar flow ratio is 10 to 30.

4. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, In step S3: The second pressure in the reaction chamber is controlled to be 10 mbar to 200 mbar.

5. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, The second molar flow ratio is 50~100.

6. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, In step S2, the oxygen source flow rate is not less than 100 mL / min, and the gallium source flow rate is 100 mL / min ~ 500 mL / min.

7. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, In step S3, the oxygen source flow rate is 60 mL / min ~ 120 mL / min, and the gallium source flow rate is 15 mL / min ~ 30 mL / min.

8. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, In step S5: The third temperature is controlled at 1000℃~1200℃, the third pressure in the reaction chamber is 10 mbar~100 mbar, and the third molar flow ratio of oxygen to gallium is 10~30.

9. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, In step S5, the gallium source flow rate is 600 mL / min ~ 1500 mL / min, and the oxygen source flow rate is 400 mL / min ~ 600 mL / min.

10. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, The output power of the oxygen ionization device is controlled to be 100 watts to 500 watts, and the pressure of the oxygen source ionization channel in the oxygen ionization device is consistent with the pressure in the reaction chamber.

11. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, The MOCVD reaction chamber is equipped with a gas injection device. The gallium source enters the reaction chamber through the gas injection device at a controlled flow rate. The oxygen source flows through the oxygen ionization device at a controlled flow rate and then enters the reaction chamber through the gas injection device. The gas ejection end face of the gas injection device in the reaction chamber is disposed opposite to the base located in the reaction chamber. The gallium oxide substrate is supported on the support surface of the base.

12. The method for epitaxial growth of gallium oxide according to claim 11, characterized in that, The oxygen ionization device is located above the gas injection device, and the distance h between the gas output end of the oxygen ionization device and the oxygen source injection port of the gas injection device does not exceed 10 cm; the distance between the gas ejection end face of the gas injection device and the bearing surface of the base does not exceed 10 cm.

13. The method for epitaxial growth of gallium oxide according to claim 1, characterized in that, The oxygen source includes an oxygen-containing gas, and the gallium source includes a mixture of a non-reactive carrier gas and a gallium-organic metal compound.

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