heteroepitaxial growth method of gallium oxide

Abstract

This invention discloses a method for heteroepitaxial growth of gallium oxide (GaO). The method includes installing an oxygen ionization device within a reaction chamber. The temperature within the reaction chamber is controlled at a first temperature not exceeding 500°C, and the pressure is controlled at a first pressure not less than 100 mbar. An oxygen source and a gallium source are introduced into the reaction chamber, with the oxygen source flow rate controlled at a minimum of 1200 mL / min, and the first molar flow ratio of oxygen to gallium controlled at a minimum of 1000. The temperature within the reaction chamber is then increased to a second temperature not exceeding 800°C, and the pressure is decreased to a second pressure not exceeding 20 mbar. The gallium source flow rate is increased, and the oxygen source flow rate is decreased to control the second molar flow ratio of oxygen to gallium not exceeding 100. A second GaO layer is grown on a first GaO layer at a growth rate of at least 5 μm / h. The growth of the first and second GaO layers is repeated to improve electron mobility and obtain a GaO epitaxial wafer with good growth quality.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material preparation technology, specifically to a heteroepitaxial 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 materials is usually vapor phase epitaxy equipment, which uses gallium-containing organometallic compounds and oxygen-containing gases as source materials, and controls the temperature and pressure inside the vapor phase epitaxy equipment to carry out epitaxial growth on the substrate.

[0004] However, for heteroepitaxial growth of gallium oxide, the large difference in thermal expansion coefficients between the heterosubstrate and the gallium oxide material, along with significant lattice mismatch, easily leads to high dislocation density. Furthermore, the decomposition efficiency of oxygen-containing gases, such as oxygen, is low. Even with increased temperatures above 700°C and increased flux, insufficient decomposition still occurs, resulting in a shortage of active oxygen atoms participating in the reaction to form gallium oxide. This easily introduces vacancies, leading to numerous defects, poor quality, and low electron mobility in the gallium oxide material. Simultaneously, the insufficient active oxygen atoms and low material growth efficiency limit the fabrication of semiconductor devices requiring thick Ga2O3 materials, resulting in very high production costs. Summary of the Invention

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

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

[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 heterogeneous 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 500℃ and the pressure to a first pressure not less than 100mbar, introduce an oxygen source and a gallium source into the reaction chamber, control the oxygen source flow rate to be not less than 1200mL / min, and control the first molar flow ratio of oxygen and gallium to be not less than 1000, so as to grow a first gallium oxide layer on the heterostructure at a growth rate of not less than 0.5μm / h;

[0010] S3: Control the temperature in the reaction chamber to rise to a second temperature not exceeding 800°C, and the pressure to drop to a second pressure not exceeding 20 mbar. Increase the gallium source flow rate and decrease the oxygen source flow rate to control the second molar flow ratio of oxygen and gallium not exceeding 100, so as to grow a second gallium oxide layer on the first gallium oxide layer at a growth rate of not less than 5 μm / h.

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

[0012] Optionally, after step S4 is completed, the following steps may also be performed:

[0013] S5: Control the temperature in the reaction chamber to rise to a third temperature not exceeding 1000°C, increase the flow rate of the gallium source, and control the third molar flow ratio of oxygen and gallium to not exceed 20, so as 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.

[0014] Optionally, in step S5, the third pressure in the reaction chamber is controlled to not exceed 20 mbar.

[0015] Optionally, in step S5, the third temperature is between 800℃ and 1000℃, the third pressure is between 10mbar and 20mbar, and the third molar flow ratio is between 10 and 20.

[0016] Optionally, the gallium source flow rate in step S5 is controlled to be 600 mL / min ~ 1200 mL / min.

[0017] Optionally, the output power of the oxygen ionization device is controlled to be between 100 watts and 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.

[0018] Optionally, in step S3, the second temperature is controlled to be between 600°C and 800°C, the second pressure is controlled to be between 10 mbar and 20 mbar, and the second molar flow ratio is controlled to be between 10 and 100.

[0019] Optionally, in step S2, the first temperature is between 400℃ and 500℃, the first pressure is between 100mbar and 500mbar, and the first molar flow ratio is between 1000 and 2000.

[0020] Optionally, the gallium source flow rate in step S3 is controlled to be no less than 150 mL / min.

[0021] Optionally, the gallium source flow rate in step S3 is 150 mL / min ~ 300 mL / min, and the gallium source flow rate in step S2 does not exceed 100 mL / min.

[0022] Optionally, the oxygen source flow rate in step S2 is 1200 mL / min to 3000 mL / min, and the oxygen source flow rate in step S3 is 120 mL / min to 1200 mL / min.

[0023] Optionally, it also includes driving the heterostructure substrate to rotate about its axis and controlling the rotation rate to not exceed 120 rpm.

[0024] 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. 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 positioned opposite to the base located in the reaction chamber. The heterogeneous substrate is supported on the support surface.

[0025] 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.

[0026] Optionally, the heterogeneous substrate includes one of an alumina substrate, a silicon substrate, a gallium nitride substrate, and an aluminum nitride substrate.

[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 heteroepitaxial growth method for gallium oxide described in this 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] When growing the first gallium oxide layer, the first temperature is controlled to not exceed 500°C and the first pressure is not less than 100 mbar. Growing the first gallium oxide layer, which plays a buffer transition role, at a lower temperature and higher pressure is beneficial to alleviate lattice mismatch and thermal mismatch. At the aforementioned temperature and pressure, combined with controlling the oxygen source flow rate to not less than 1200 mL / min and controlling the first molar flow ratio of oxygen to gallium to not less than 1000, the growth layer with this buffer transition role can grow rapidly at a growth rate of not less than 0.5 μm / h.

[0031] When growing the second gallium oxide layer, the temperature is controlled to rise to no more than 800 °C and the pressure is controlled to drop to no more than 20 mbar. By increasing the gallium source flow rate and decreasing the oxygen source flow rate to control the second molar flow ratio of oxygen and gallium to be no more than 100, the second gallium oxide layer can be grown rapidly at a growth rate of no less than 5 μm / h, reducing surface defects and promoting surface smoothness to improve electron mobility.

[0032] The growth of the first gallium oxide layer can quickly alleviate lattice mismatch and thermal mismatch, and the growth of the second gallium oxide layer can quickly achieve good quality growth. Repeated growth of the first gallium oxide layer and the second gallium oxide layer can help to cover up dislocation bending that may occur during the growth process, thereby improving electron mobility. 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 gas injection device of the epitaxial growth equipment in an embodiment of the present invention.

[0036] Figure 4 This is a schematic diagram of a gallium nitride epitaxial structure 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. Heterogeneous 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 method for heteroepitaxial growth of gallium oxide, referring to... Figure 1 The gallium oxide heteroepitaxial growth method 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 heterogeneous 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 500℃ and the pressure to a first pressure not less than 100mbar, introduce an oxygen source and a gallium source into the reaction chamber, control the oxygen source flow rate to be not less than 1200mL / min, and control the first molar flow ratio of oxygen and gallium to be not less than 1000, so as to grow a first gallium oxide layer on the heterostructure at a growth rate of not less than 0.5μm / h;

[0049] S3: Control the temperature in the reaction chamber to rise to a second temperature not exceeding 800°C, and the pressure to drop to a second pressure not exceeding 20 mbar. Increase the gallium source flow rate and decrease the oxygen source flow rate to control the second molar flow ratio of oxygen and gallium not exceeding 100, so as to grow a second gallium oxide layer on the first gallium oxide layer at a growth rate of not less than 5 μm / h.

[0050] S4: Repeat steps S2 to 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 an 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, avoiding the problem of insufficient oxygen decomposition. 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, refer to Figure 2The reaction chamber 10 is an MOCVD reaction chamber. In this embodiment, the oxygen ionization device 14 is used in conjunction with the MOCVD reaction chamber 10: the oxygen ionization device 14 is located upstream of the gas injection device 21, avoiding the need to place the substrate in the plasma region, which is beneficial for high-quality gallium oxide epitaxial growth; the oxygen source is activated by plasma before entering the gas injection device 21, and the activation level of the oxygen source can be easily controlled by controlling 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 entering the oxygen ionization device 14; on the other hand, the gallium source enters the reaction chamber 10 directly through the gas injection device 21 and is activated by thermal decomposition, and the activation level of the gallium source can also be easily controlled by controlling the flow rate of the gallium source and the temperature inside the reaction chamber 10. More importantly, the diffusion of the ionized oxygen source and the entering gallium source in 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 3The 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 3 The oxygen ionization device 14 is located 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 applied in time to the reaction of O and Ga in the reaction chamber 10.

[0060] In some embodiments, the heterostructure 100 can be one of an Al2O3 substrate, a Si substrate, a GaN substrate, and an AlN substrate. However, the growth of the heterostructure 100 involves significant lattice mismatch and thermal mismatch, and it is necessary to minimize the impact of this mismatch on epitaxial quality during gallium oxide growth.

[0061] In some embodiments, the carrier surface of this embodiment has a plurality of recesses for placing a heterogeneous substrate. The recesses are arranged around the central region of the substrate carrier so that each recess is exposed to the environment of the reaction space.

[0062] In this embodiment, the gallium oxide heteroepitaxial growth method is performed using an MOCVD epitaxial growth apparatus. Specifically, refer to... Figure 2The 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 substrate to form an isolation space, thus 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, communicating with the isolation space within the reaction chamber 10. During epitaxial growth, a chemically inert purging gas can be introduced into the isolation space through the purging device. Driven by gas pressure, the purging gas enters the reaction chamber 10 through the gap between the isolation device 18 and the base 16, maintaining a slightly positive pressure in the isolation space compared to the gas pressure in the reaction chamber 10. This prevents 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 apparatus. In some specific embodiments, the isolation device 18 is made of graphite or molybdenum.

[0063] In step S1 of some embodiments, referring to Figure 2 and Figure 4 The heterogeneous substrate 100 is placed in the recess on the base 16 inside the reaction chamber 10, and the output power applied to the oxygen ionization device 14 is controlled to be no less than 100 watts.

[0064] In some embodiments, the output power is controlled to be 100 watts to 500 watts.

[0065] In some embodiments, the pressure in the oxygen supply ionization 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 ionization channel of the oxygen ionization device 14 is simultaneously adjusted to be consistent with the pressure inside the reaction chamber.

[0066] 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.

[0067] 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 heterogeneous substrate on the base 16 also rotates synchronously.

[0068] In some embodiments, the rotational speed of the rotating device 15 is controlled to not exceed 120 rpm.

[0069] In step S2 of some embodiments, reference is made to Figure 2 and Figure 4After the heterostructure 100 is placed, a first gallium oxide layer 201 is formed on the heterostructure 100. Specifically, after controlling the temperature in the reaction chamber 10 to a first temperature not exceeding 500°C and the pressure to a first pressure not less than 100 mbar, a certain flow rate of gallium source is introduced into the reaction chamber 10 through the gallium source injection pipe 13, and a certain flow rate of oxygen source is introduced into the oxygen ionization device 14 through the first injection pipe 121. The oxygen source is ionized and then ejected through the second injection pipe 122. The flow rate of oxygen source entering the first injection pipe 121 is controlled to be not less than 1200 mL / min, and the first molar flow ratio of oxygen to gallium is controlled to be not less than 1000, so that the first gallium oxide layer 201 is grown on the heterostructure 100 at a growth rate of not less than 0.5 μm / h.

[0070] 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.

[0071] In this embodiment, since a heterogeneous substrate is used for gallium oxide epitaxy, directly depositing a gallium oxide epitaxial layer on a heterogeneous substrate with a large difference in lattice constant from gallium oxide can easily lead to significant dislocations and / or stress at the interface. Therefore, it is necessary to first grow a buffer layer on the heterogeneous substrate. In this embodiment, the first gallium oxide layer 201 is grown under conditions of a first temperature not exceeding 500°C and a first pressure not less than 100 mbar as a buffer transition growth layer. Gallium oxide layers grown under lower temperature and higher pressure conditions tend to exhibit a three-dimensional island-like growth pattern, which can alleviate dislocations caused by large lattice mismatch and thermal mismatch, thus benefiting the quality of subsequently grown gallium oxide layers. Furthermore, considering that the oxygen source enters the reaction chamber 10 only after being ionized by the oxygen ionization device 14, and that the high temperature (above 700°C) in the reaction chamber 10, combined with the effect of active oxygen, is more conducive to accelerating the growth rate, the chamber temperature of no more than 500°C combined with the pressure control of no less than 100 mbar can easily suppress the reaction level of active oxygen. Therefore, in this step, the oxygen source flow rate is controlled to be no less than 1200 mL / min, and the first molar flow ratio of oxygen to gallium is controlled to be no less than 1000. By increasing the oxygen flow rate supplied to the oxygen ionization device 14, the amount of active oxygen required to cooperate with the decomposed gallium source for epitaxial growth in the reaction chamber 10 is increased, and the growth rate of the first gallium oxide layer is ensured to be no less than 0.5 μm / h.

[0072] Optionally, the first temperature shall not exceed 500°C, for example, it may be 400°C to 500°C.

[0073] Optionally, the first pressure is not less than 100 mbar. Preferably, the first pressure is between 100 mbar and 500 mbar.

[0074] Optionally, the first molar flow rate ratio of oxygen to gallium is not less than 1000, for example, it can be 1000~2000. Optionally, the flow rate of the oxygen source is between 1000 mL / min and 3000 mL / min, and the flow rate of the gallium source does not exceed 100 mL / min, for example, it can be 30 mL / min, 60 mL / min, 90 mL / min, etc. Here, the first molar flow rate ratio of oxygen to gallium refers to the molar flow rate ratio of oxygen atoms to gallium atoms.

[0075] In this application, the gallium source comprises a mixture of a non-reactive carrier gas and a gallium-containing organometallic compound. The oxygen source includes an oxygen-containing gas.

[0076] In this embodiment, the growth rate of the first gallium oxide layer 201 is 0.8 μm / h ~ 2 μm / h.

[0077] In some embodiments, the thickness of the first gallium oxide layer 201 is between 50 nm and 100 nm. The specific thickness can be flexibly adapted according to process requirements.

[0078] In step S3 of some embodiments, reference is made to Figure 2 and Figure 4 After forming the first gallium oxide layer 201, a second gallium oxide layer 202 is grown on the first gallium oxide layer 201. Specifically, the temperature in the reaction chamber 10 is controlled to rise to a second temperature not exceeding 800°C, and the pressure is controlled to drop to a second pressure not exceeding 20 mbar. The gallium source flow rate is increased and the oxygen source flow rate is decreased to control the second molar flow ratio of oxygen to gallium not exceeding 100, so that the second gallium oxide layer 202 is grown on the first gallium oxide layer 201 at a growth rate of not less than 5 μm / h. Thus, this step, through higher temperature and lower pressure, can quickly achieve lateral growth and merging of gallium oxide material, which is beneficial to surface flatness. At the same time, controlling the second molar flow ratio of oxygen to gallium not exceeding 100 is beneficial because if too much active oxygen is supplied to the reaction chamber 10 after ionization by the oxygen ionization device 14, the excess active oxygen can easily lead to too many point defects in the epitaxial layer, which is detrimental to the epitaxial quality. The control in step S3 is beneficial to reduce point defects in the gallium oxide material and improve crystal quality and electron mobility.

[0079] Optionally, the second temperature does not exceed 800°C, for example, the second temperature is between 600°C and 800°C. The second pressure does not exceed 20 mbar, for example, it can be between 10 mbar and 20 mbar. The second molar flow ratio of the oxygen source and the gallium source is 10 to 100.

[0080] Optionally, the increase in the gallium source flow rate does not exceed 270 mL / min, for example, the gallium source flow rate is not less than 150 mL / min, for example, 150 mL / min ~ 300 mL / min. Optionally, the decrease in the oxygen source flow rate does not exceed 2400 mL / min, for example, the oxygen source flow rate is 120 mL / min ~ 1200 mL / min.

[0081] Optionally, refer to Figure 4 The growth rate of the second gallium oxide layer 202 is relatively higher than that of the first gallium oxide layer 201, enabling rapid lateral growth and merging of gallium oxide material and reducing point defects. The growth rate of the second gallium oxide layer 202 is greater than that 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 6 μm / h to 10 μm / h.

[0082] Optionally, refer to Figure 4 The thickness of the second gallium oxide layer 202 is greater 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 450 nm. Optionally, the thickness of the second gallium oxide layer 202 is 50 nm to 500 nm.

[0083] In step S4 of some embodiments, referring 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 repeated growth of the first gallium oxide layer 201 and the second gallium oxide layer 202 helps to bury the dislocation bending generated at the bottom.

[0084] 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 exceeding 1000°C, increasing the flow rate of the gallium source, and controlling the third molar flow ratio of oxygen and gallium not exceeding 20, so as 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.

[0085] Reference Figure 2 and Figure 4A third gallium oxide layer 203 is grown on the last second gallium oxide layer 202 grown in step S4. Specifically, the temperature inside the reaction chamber 10 is controlled to rise to a third temperature not exceeding 1000°C, the flow rate of the gallium source is increased, and the third molar flow rate ratio of oxygen to gallium is controlled to not exceed 20, so that the third gallium oxide layer 203 is grown on the gallium oxide layer obtained in step S4 at a growth rate of not less than 20 μm / h. The temperature difference between the third temperature and the second temperature does not exceed 400°C, the pressure difference between the third pressure and the second pressure does not exceed 10 mbar, and the difference between the third molar flow rate ratio of oxygen source to gallium source and the first molar flow rate ratio of oxygen source to gallium source does not exceed 2000. This embodiment uses the above-mentioned low O / Ga ratio, high temperature, and low pressure to grow the third gallium oxide layer 203, which can rapidly increase the thickness of the Ga2O3 material and further improve the quality of the Ga2O3 material.

[0086] Optionally, the third temperature does not exceed 1000℃, for example, it can be 800℃~1000℃. The third pressure does not exceed 20 mbar, for example, it can be 10 mbar~20 mbar. The third molar flow ratio of the oxygen source and the gallium source does not exceed 20, for example, it can be 10~20.

[0087] Optionally, the increase in the gallium source flow rate does not exceed 1000 mL / min. For example, the gallium source flow rate does not exceed 1200 mL / min, and preferably, the gallium source flow rate is 600 mL / min to 1200 mL / min.

[0088] Optionally, the flow rate of the oxygen source shall not exceed 500 mL / min, for example, the flow rate of the oxygen source is 480 mL / min.

[0089] Optionally, refer to Figure 4 The growth rate of the third gallium oxide layer 203 is greater than the growth rate of the second gallium oxide layer 202. The difference between the growth rate of the third gallium oxide layer 203 and the growth rate of the second gallium oxide layer 202 does not exceed 30 μm / h. 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. Optionally, the growth rate of the third gallium oxide layer 203 does not exceed 40 μm / h.

[0090] Optionally, refer to Figure 4 The thickness of the third gallium oxide layer 203 is greater than the thickness of the first gallium oxide layer 201, and the thickness of the third gallium oxide layer 203 is greater than the thickness of the second gallium oxide layer 202. The difference between the thickness of the third gallium oxide layer 203 and the thickness of the second gallium oxide layer 202 is greater than 9500 nm. Alternatively, the thickness of the third gallium nitride layer may not exceed 10000 nm.

[0091] The implementation of the gallium oxide heteroepitaxial 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.

[0092] Example 2

[0093] This embodiment provides an epitaxial growth apparatus for performing the heteroepitaxial growth method of gallium oxide in Embodiment 1.

[0094] 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.

[0095] Optionally, refer to Figure 2 The 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.

[0096] Optionally, refer to Figure 2An 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] The present invention will now be described in detail with reference to specific embodiments. An FG5001 plasma generator is used as the oxygen ionization device. The growth rate is calculated using the MOCVD online monitoring system viperRTC-LSS, which is specifically installed on top of the gas injection device 21, and the installation and operation methods are conventional techniques in the art. Background concentration and electron mobility are measured using a Nanometrics Hall effect meter.

[0101] Example 1

[0102] This embodiment provides a heteroepitaxial 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.

[0103] Six circumferential recesses are arranged on the base 16 within the reaction chamber 10, each recess being sized 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, which is a plasma generator, 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.

[0104] Heteroepitaxy methods for gallium oxide include:

[0105] S1: Place each alumina substrate in each cavity, control the application of 10 kV AC current to the inner and outer electrodes of the oxygen ionization device 14 (i.e., the plasma generator), and the pressure in the oxygen source ionization channel is 100 mbar, so that the output power of the oxygen ionization device 14 is controlled to 100 watts.

[0106] S2: Control the temperature of reaction chamber 10 to rise to 400℃, the pressure of reaction chamber 10 to 100 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 60 mL / min, introduce oxygen as oxygen source into first injection pipe 121 and control the flow rate to 2400 mL / min, wherein the molar flow ratio of oxygen to gallium, i.e. O / Ga ratio, is 1000, 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 2 μm / h;

[0107] 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 is raised to 700 ℃. After adjusting the growth pressure and the pressure in the oxygen source ionization channel to 20 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 240 mL / min, adjust the oxygen flow rate into first injection pipe 121 to 300 mL / min, control the O / Ga ratio to 30, until the growth thickness of the second gallium oxide layer 202 is 500 nm and the growth rate of the second gallium oxide layer 202 is 9 μm / h;

[0108] S4: Repeat steps S2 and S3 to execute the loop 20 times;

[0109] 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 20 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 for 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. The O / Ga ratio is 10 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 40 μm / h.

[0110] 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 60 cm⁻¹. 2 / (V·s), the background concentration (i.e., intrinsic carrier concentration) is: 5 × 10 16 cm -3 .

[0111] Example 2

[0112] This embodiment provides a heteroepitaxial 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.

[0113] The difference between this epitaxial growth equipment and the equipment used in Example 1 is that:

[0114] The base 16 within the reaction chamber has 12 circumferential recesses, each configured to support a 2-inch substrate; the diameter of the top surface of the base 16 is 260 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 2 cm.

[0115] Heteroepitaxy methods for gallium oxide include:

[0116] S1: Place each silicon substrate in each cavity, control the application of 10 kV AC current to the inner and outer electrodes of the oxygen ionization device, and control the pressure in the oxygen source ionization channel to be 400 mbar, so that the output power of the oxygen ionization device is controlled to be 100 watts.

[0117] S2: Control the temperature of the reaction chamber to rise to 450℃, the pressure of the reaction chamber to 400 mBar, control the rotation speed of the rotating device 15 to 50 rpm, introduce trimethylgallium and nitrogen as a mixed gas into the gallium source injection pipe 13 and control the flow rate to 60 mL / min, introduce oxygen as an oxygen source into the first injection pipe 121 and control the flow rate to 2400 mL / min, wherein the molar flow ratio of oxygen to gallium, i.e. O / Ga ratio, is 1000, 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 1 μm / h;

[0118] 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 is raised to 600 ℃. 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 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 300 mL / min, adjust the oxygen flow rate into first injection pipe 121 to 1200 mL / min, control the O / Ga ratio to 100, until the growth thickness of the second gallium oxide is 500 nm and the growth rate of the second gallium oxide layer 202 is 10 μm / h;

[0119] S4: Repeat steps S2 and S3, so that the loop is executed 20 times;

[0120] 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 800°C. After adjusting the growth pressure and the pressure in the oxygen source ionization channel to 10 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 600 mL / min, introduce oxygen into the first injection pipe 121 and control the flow rate to 480 mL / min, with an O / Ga ratio of 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.

[0121] 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 70 cm⁻¹. 2 / (V·s), the background concentration (i.e., intrinsic carrier concentration) is: 5 × 10 16 cm -3 .

[0122] Example 3

[0123] This embodiment provides a heteroepitaxial 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.

[0124] The difference between this epitaxial growth equipment and the equipment in Example 1 is:

[0125] The base 16 within the reaction chamber 10 has 19 recesses arranged in different circumferential rings, each recess being sized to support a 2-inch substrate. The base 16 is a graphite disk, and the diameter of its top surface 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.

[0126] Heteroepitaxy methods for gallium oxide include:

[0127] S1: Place each alumina substrate in each cavity, control the application of 10 kV AC current to the inner and outer electrodes of the oxygen ionization device 14, and control the pressure inside the oxygen source ionization channel 144 to be 100 mbar, so that the output power of the oxygen ionization device 14 is controlled to be 100 watts.

[0128] S2: Control the temperature of reaction chamber 10 to rise to 450℃, the pressure of reaction chamber 10 to 100 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 30 mL / min, introduce oxygen as oxygen source into first injection pipe 121 and control the flow rate to 2400 mL / min, wherein the molar flow ratio of oxygen to gallium, i.e. O / Ga ratio, is 2000, 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 1 μm / h;

[0129] 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 is raised to 800 ℃, 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 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 150 mL / min, adjust the oxygen flow rate into first injection pipe 121 to 120 mL / min, control the O / Ga ratio to 20, 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 6 μm / h;

[0130] S4: Repeat steps S2 and S3 to execute the loop 20 times;

[0131] 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 900 ℃. 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 600 mL / min, introduce oxygen into the first injection pipe 121 and control the flow rate to 480 mL / min, with an O / Ga ratio of 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.

[0132] 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 70 cm⁻¹. 2 / (V·s), the background concentration (i.e., intrinsic carrier concentration) is: 4 × 10 16 cm -3 .

[0133] Example 4

[0134] This embodiment provides a heteroepitaxial 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.

[0135] The difference between the epitaxial growth equipment and Example 1 is that the distance from the gas ejection end face 213 of the gas injection device 21 to the base bearing surface is 5cm.

[0136] Heteroepitaxy methods for gallium oxide include:

[0137] S1: Place each alumina 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 inside the oxygen source ionization channel 144 to be 200 mbar, so that the output power of the oxygen ionization device 14 is controlled to be 500 watts.

[0138] S2: Control the temperature of reaction chamber 10 to rise to 500℃, the pressure of reaction chamber 10 to 200 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 30 mL / min, introduce oxygen as oxygen source into first injection pipe 121 and control the flow rate to 1200 mL / min, wherein the molar flow ratio of oxygen to gallium, i.e. O / Ga ratio, is 1000, until the growth thickness of the first gallium oxide layer 201 is 50 nm, and the growth rate of the first gallium oxide layer 201 is 0.8 μm / h;

[0139] 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 is raised to 800 ℃, after adjusting the growth pressure and the pressure in the oxygen source ionization channel to 20 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 300 mL / min, adjust the oxygen flow rate into first injection pipe 121 to 120 mL / min, control the O / Ga ratio to 10, 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 10 μm / h;

[0140] S4: Repeat steps S2 and S3 to execute the loop 20 times;

[0141] 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 900 ℃. 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 600 mL / min, introduce oxygen into the first injection pipe 121 and control the flow rate to 480 mL / min, with an O / Ga ratio of 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.

[0142] 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 50 cm⁻¹. 2 / (V·s), the background concentration (i.e., intrinsic carrier concentration) is: 5 × 10 16 cm -3 .

[0143] 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 heteroepitaxial 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 heterogeneous 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 of 400℃~500℃ and the pressure to a first pressure of 100mbar~500mbar, introduce an oxygen source and a gallium source into the reaction chamber, control the oxygen source flow rate to be between 1200mL / min~3000mL / min, and control the first molar flow ratio of oxygen to gallium to be between 1000~2000, so as to grow a first gallium oxide layer on the heterostructure at a growth rate of not less than 0.5μm / h; S3: Control the temperature in the reaction chamber to rise to a second temperature of 600℃~800℃, and the pressure to drop to a second pressure of 10mbar~20mbar. Increase the gallium source flow rate and decrease the oxygen source flow rate to control the second molar flow ratio of oxygen and gallium to be between 10 and 100, so as to grow a second gallium oxide layer on the first gallium oxide layer at a growth rate of not less than 5μm / h. S4: Repeat steps S2 to 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 800℃~1000℃, increase the flow rate of the gallium source, control the third pressure in the reaction chamber to be between 10mbar and 20mbar, and control the third molar flow ratio of oxygen and gallium to be between 10 and 20, so as to grow a third gallium oxide layer on the gallium oxide layer obtained in step S4 at a growth rate of not less than 20μm / h.

2. The heteroepitaxial growth method for gallium oxide according to claim 1, characterized in that, In step S5, the third pressure in the reaction chamber is controlled to not exceed 20 mbar.

3. The heteroepitaxial growth method for gallium oxide according to claim 1, characterized in that, The gallium source flow rate in step S5 is controlled to be 600 mL / min ~ 1200 mL / min.

4. The heteroepitaxial growth method for gallium oxide according to claim 1, characterized in that, The output power of the oxygen ionization device is controlled to be between 100 watts and 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.

5. The heteroepitaxial growth method for gallium oxide according to claim 1, characterized in that, The gallium source flow rate in step S3 shall not be less than 150 mL / min.

6. The heteroepitaxial growth method for gallium oxide according to claim 5, characterized in that, The gallium source flow rate in step S3 is 150 mL / min ~ 300 mL / min, and the gallium source flow rate in step S2 does not exceed 100 mL / min.

7. The heteroepitaxial growth method for gallium oxide according to claim 1, characterized in that, The oxygen source in step S3 is 120 mL / min ~ 1200 mL / min.

8. The heteroepitaxial growth method for gallium oxide according to claim 1, characterized in that, It also includes driving the heterogeneous substrate to rotate about its axis, and controlling the rotation speed to not exceed 120 rpm.

9. The method for heteroepitaxial 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 heterogeneous substrate is supported on the support surface of the base.

10. The method for heteroepitaxial growth of gallium oxide according to claim 9, 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.

11. The method for heteroepitaxial growth of gallium oxide according to claim 1, characterized in that, The heterogeneous substrate includes one of an alumina substrate, a silicon substrate, a gallium nitride substrate, and an aluminum nitride substrate.

12. The method for heteroepitaxial 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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