Gas-collecting ring for gallium oxide epitaxy and mocvd apparatus for gallium oxide epitaxy

Abstract

The application discloses a gas collecting ring for gallium oxide epitaxy and a MOCVD equipment for gallium oxide epitaxy with the same. The gas collecting ring for gallium oxide epitaxy comprises a ring body, the ring body comprises oppositely arranged first and second end faces, and an inner surface and an outer surface between the first and second end faces, the first and second end faces, the inner surface and the outer surface jointly enclose a cavity, a plurality of first gas flow holes are formed in the inner surface and communicated with the cavity, and a plurality of second gas flow holes are formed in the outer surface and communicated with the cavity. The gas collecting ring for gallium oxide epitaxy and the MOCVD equipment for gallium oxide epitaxy can solve the problem that the components in the existing equipment are oxidized by the oxygen required by the gallium oxide epitaxy.

Description

Technical Field

[0001] This invention relates to the field of epitaxial thin film technology, and in particular to a gas collecting ring for gallium oxide epitaxial growth and an MOCVD apparatus for gallium oxide epitaxy incorporating the gas collecting ring. Background Technology

[0002] Gallium oxide (Ga2O3), a fourth-generation semiconductor material, has a bandgap greater than 4 eV, making it an ultra-wide bandgap semiconductor material. It can be used to fabricate high-power devices and operate under high-temperature conditions. Theoretically, its power loss is 1 / 3400 that of Si devices and 1 / 10 that of SiC devices. Furthermore, Ga2O3 has high breakdown voltage, low on-resistance, and good radio frequency characteristics similar to gallium nitride, and will be used in solar-blind, power electronic, and deep ultraviolet devices.

[0003] Epitaxial devices for Ga2O3 include MBE, MOCVD, Mist-CVD, and HVPE. Among these, MBE devices have extremely few defects, allowing for effective control of carrier concentration, and offer significant advantages in preparing Ga2O3-based heterojunctions and superlattices. However, they are relatively expensive and have low deposition rates, making them less suitable for industrial production. Mist-CVD... CVD equipment has a simple structure and low cost, but the technology is not yet fully developed. It is mainly used to prepare α-phase Ga2O3 thin films, so it cannot completely replace other deposition technologies in the industrialization process. HVPE obtains materials with high purity, fast growth rate, and simple process, and can prepare β-Ga2O3 and α-Ga2O3. However, the surface of the grown thick film is relatively rough, generating a large number of defects. It is difficult to control the thickness uniformity of large-size epitaxial films. The intellectual property rights related to its single crystal preparation and thin film growth technology and equipment are completely in Japan. MOCVD can form films on a large area with high growth rate, making it very suitable for industrial production. In the deposition of Ga2O3 epitaxial films, the films have very low defects and the electron mobility is close to the theoretical prediction value. It has great potential in the preparation of high-performance power devices. Since the equipment can usually achieve substrate heating above 800 degrees Celsius, it is very advantageous for achieving high-concentration aluminum (Al) doping. At present, MOCVD for epitaxial Ga2O3 is in the laboratory stage and there are no industrial mass-production models. The existing MOCVD equipment for epitaxial GaN is well-suited for epitaxial Ga2O3 films. However, the large disks, heating wires or heating plates used in GaN epitaxy, as well as the metal components inside the equipment, will be oxidized and lose their heating capacity or have their service life shortened after oxygen is introduced.

[0004] In the prior art, there have been improvements to existing MOCVD equipment for epitaxial GaN to be used for epitaxial Ga2O3 thin films. For example, utility model patent CN215404508 improves the existing MOCVD reaction chamber for GaN by using a silicon carbide (SiC) cover to cover the outer surface of the tungsten filament heater, and several grooves are formed on the outer surface of the silicon carbide cover to place the substrate and prevent oxygen from diffusing into the area where the tungsten filament is located and oxidizing it. Although the carrier disk made of SiC material has the advantages of long service life and resistance to oxidation, SiC has a high impurity content, high hardness, is difficult to machine, and its cost is much higher than that of traditional graphite disks, making it unsuitable for mass production. For example, invention patent CN114908419A discloses a method for preparing gallium oxide thin films on homogeneous gallium oxide substrates. This method uses a laser spot to cover the entire top of a graphite tray. Because the high-resistivity gallium oxide substrate absorbs very little laser light, the laser can directly irradiate the graphite tray, thereby achieving uniform heating of the high-resistivity gallium oxide substrate and preparing high-quality, uniformly thick homogeneous epitaxial gallium oxide thin films. While this method introduces laser heating, the laser power is limited, and the beam quality is not high. Large-scale mass production requires the simultaneous use of too many lasers and complex optical systems, introducing many uncertainties to the precise temperature control of the heating system.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a gas collecting ring for Ga2O3 epitaxial growth and an MOCVD device for gallium oxide epitaxy with the gas collecting ring, which can solve the problem of oxidation of internal components of existing equipment by the oxygen required for gallium oxide epitaxy.

[0007] To achieve the above objectives, embodiments of the present invention provide a gas collecting ring for gallium oxide epitaxy, comprising an annular body, wherein the annular body includes a first end face, a second end face, and an inner surface and an outer surface located between the first end face and the second end face, the first end face, the second end face, the inner surface and the outer surface together enclosing a cavity, a plurality of first gas flow holes communicating with the cavity are provided on the inner surface, and a plurality of second gas flow holes communicating with the cavity are provided on the outer surface.

[0008] In one or more embodiments of the present invention, a plurality of the first airflow holes are uniformly distributed on the inner surface of the annular body.

[0009] In one or more embodiments of the present invention, a plurality of second airflow holes are arranged circumferentially along the annular body, and the distance between the second airflow holes and the second end face is less than the distance between the second airflow holes and the first end face.

[0010] In one or more embodiments of the present invention, the diameter of the first airflow hole and / or the second airflow hole is 2 to 10 mm, and the spacing between adjacent first airflow holes and / or adjacent second airflow holes is 2 to 10 mm.

[0011] In one or more embodiments of the present invention, the diameter of the first airflow hole and / or the second airflow hole is 3-5 mm, and the spacing between adjacent first airflow holes and / or adjacent second airflow holes is 3-5 mm.

[0012] In one or more embodiments of the present invention, a plurality of third airflow holes communicating with the chamber are provided on the first end face.

[0013] In one or more embodiments of the present invention, the diameter of the third airflow hole is 2 to 10 mm, and the spacing between adjacent third airflow holes is 2 to 10 mm.

[0014] In one or more embodiments of the present invention, the diameter of the third airflow hole is 3-5 mm, and the spacing between adjacent third airflow holes is 3-5 mm.

[0015] In one or more embodiments of the present invention, an anti-oxidation coating is deposited on all or part of the first end face, the second end face, the inner surface, and the outer surface.

[0016] In one or more embodiments of the present invention, the anti-oxidation coating includes a SiC coating.

[0017] In one or more embodiments of the present invention, the material of the annular body includes molybdenum.

[0018] In one or more embodiments of the present invention, the straight-line distance between the inner and outer surfaces of the annular body is 5 to 15 mm.

[0019] The present invention also provides an MOCVD apparatus for gallium oxide epitaxy, comprising a housing, the aforementioned gas collecting ring for gallium oxide epitaxy, a carrier plate, and a heating assembly. A reaction chamber is formed within the housing, and an inlet and an outlet are provided on the housing. The gas collecting ring is disposed within the reaction chamber, and a mounting cavity is formed in the middle of the gas collecting ring. The carrier plate is disposed within the mounting cavity for supporting a substrate. The heating assembly is disposed within the mounting cavity and located below the carrier plate, and the heating assembly is used to heat the carrier plate.

[0020] In one or more embodiments of the present invention, the carrier disk is rotatably disposed within the mounting cavity, and the material of the carrier disk includes graphite.

[0021] In one or more embodiments of the present invention, both the surface of the carrier plate and the surface of the heating component are deposited with an anti-oxidation coating.

[0022] In one or more embodiments of the present invention, the anti-oxidation coating includes a SiC coating.

[0023] In one or more embodiments of the present invention, the heating assembly includes a heating plate, which is formed by winding a heating wire. The heating wire is made of a material including an iron-chromium-aluminum alloy, a nickel-chromium alloy, an iron-chromium-aluminum alloy with Al2O3 coating, or a nickel-chromium alloy with Al2O3 coating.

[0024] In one or more embodiments of the present invention, the heating assembly includes a heating electrode connected to the heating plate.

[0025] Compared with the prior art, the gas collecting ring for gallium oxide epitaxy in the embodiments of the present invention, through the setting of the internal cavity of the gas collecting ring and the air flow holes on the inner and outer surfaces, allows the reaction gas to flow into the internal cavity of the gas collecting ring through the first air flow hole on the inner surface of the gas collecting ring, and then be discharged through the second air flow hole below the outer surface of the gas collecting ring. This reduces the amount of gas inside the mounting cavity where the support plate is located, and also allows the gas to flow out of the mounting cavity and the reaction cavity evenly. At the same time, it reduces the contact deposition of the reaction gas with the inner wall of the reaction cavity and reduces the number of times the reaction cavity needs to be cleaned.

[0026] The gas collecting ring for gallium oxide epitaxy according to the embodiments of the present invention can effectively prevent oxidation by oxygen used in gallium oxide epitaxy by depositing an anti-oxidation coating, thereby extending its service life.

[0027] The MOCVD equipment for gallium oxide epitaxy according to the present invention reduces the amount of reaction gas flowing into the lower space of the support disk by adjusting the gas collecting ring with a suitable inner diameter and cooperating with a support disk of appropriate size, so that more reaction gas flows out from the second gas flow hole below the gas collecting ring, thereby extending the life of internal metal components and heating components.

[0028] The MOCVD apparatus for gallium oxide epitaxy according to embodiments of the present invention can further prevent the introduced oxygen from oxidizing it by depositing an anti-oxidation coating on the surface of internal components and by changing the material of the heating wire to use an anti-oxidation material. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the gas collecting ring for gallium oxide epitaxy according to one embodiment of the present invention;

[0030] Figure 2This is a schematic diagram of the structure of an MOCVD device for gallium oxide epitaxy according to an embodiment of the present invention. Detailed Implementation

[0031] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0032] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0033] As mentioned in the background section, Ga2O3 is widely used in solar-blind, power electronics, and deep ultraviolet devices due to its excellent properties. However, existing MOCVD equipment for Ga2O3 epitaxy is still in the laboratory stage, with no industrial-scale production models available. Since the existing MOCVD equipment structure for GaN epitaxy is well-suited for Ga2O3 thin film epitaxy, various techniques have emerged to improve the structure of GaN MOCVD equipment to make it suitable for Ga2O3 thin film epitaxy. However, these improved MOCVD equipment all have some drawbacks, such as high cost, difficulty in fabrication, or difficulty in controlling the heating temperature.

[0034] Therefore, this invention improves upon existing MOCVD equipment for epitaxial GaN to propose a MOCVD device suitable for Ga2O3 epitaxy. This device utilizes the configuration of airflow holes on the inner and outer surfaces of the gas collecting ring's internal chamber. The reaction gas flows into the internal chamber through a first airflow hole on the inner surface of the gas collecting ring and then exits through a second airflow hole below the outer surface of the gas collecting ring. This reduces the contact time between the reaction gas (oxygen) and the reaction chamber and its internal components, preventing oxidation of the components and extending their lifespan. Furthermore, the use of a heating wire made of a special material improves the temperature control accuracy of the reaction chamber while maintaining low cost.

[0035] like Figure 1As shown, one embodiment of the present invention provides a gas collecting ring 10 for gallium oxide epitaxy, applied in an MOCVD device for epitaxial Ga2O3 thin films. The gas collecting ring 10 includes an annular body, comprising a first end face 101, a second end face 102 disposed opposite to each other, and an inner surface 103 and an outer surface 104 located between the first end face 101 and the second end face 102. The inner surface 103 and the outer surface 104 are nested together, with a linear distance of 5-15 mm between them. The first end face 101 and the second end face 102 are respectively disposed at both ends of the inner surface 103 and the outer surface 104 and connect the inner surface 103 and the outer surface 104. The first end face 101, the second end face 102, the inner surface 103, and the outer surface 104 together enclose a cavity. In this embodiment, the first end face 101 and the second end face 102 are two annular end faces. An anti-oxidation coating is deposited on all or part of the inner surface 103, outer surface 104, first end face 101, and second end face 102 of the annular body. In one specific embodiment, the anti-oxidation coating is made of SiC, and the annular body is made of molybdenum.

[0036] A plurality of first airflow holes 1031 are formed on the inner surface 103 of the annular body. In this embodiment, the diameter of the first airflow holes 1031 is 2-10 mm, preferably 3-5 mm. The plurality of first airflow holes 1031 are evenly distributed on the inner surface 103, and the spacing between adjacent first airflow holes 1031 is 2-10 mm, preferably 3-5 mm.

[0037] A plurality of second airflow holes 1041 are formed on the outer surface 104 of the annular body. The plurality of second airflow holes 1041 are evenly arranged along the circumference of the annular body, and the distance between the second airflow hole 1041 and the second end face 102 is much smaller than the distance between the second airflow hole 1041 and the first end face 101; that is, the second airflow holes 1041 are formed on the edge of the outer surface 104 near the second end face 102. In this embodiment, the diameter of the second airflow hole 1041 is 2~10mm, preferably 3~5mm. The spacing between adjacent second airflow holes 1041 is 2~10mm, preferably 3~5mm.

[0038] In other embodiments, a plurality of third airflow holes 1011 are further provided on the first end face 101 of the annular body. In this embodiment, the diameter of the third airflow holes 1011 is 2-10 mm, preferably 3-5 mm. The plurality of third airflow holes 1011 are evenly distributed on the first end face 101, and the spacing between adjacent third airflow holes 1011 is 2-10 mm, preferably 3-5 mm.

[0039] In the above embodiment, the reaction gas enters the cavity inside the annular body from the first airflow hole 1031 on the inner surface 103 of the annular body and / or the third airflow hole 1011 on the first end face 101, and then flows out through the second airflow hole 1041 at the lower end of the outer surface 104 of the annular body. When the gas collecting ring 10 is set in the reaction cavity, it can effectively prevent the reaction gas from having too much contact with the side wall of the reaction cavity, causing oxidation deposition.

[0040] like Figure 2 According to one embodiment of the present invention, an MOCVD apparatus for gallium oxide epitaxy is provided, including a housing 20, a gas collecting ring 10 for gallium oxide epitaxy, a support disk 30, and a heating assembly 40. A cylindrical reaction chamber 21 is formed inside the housing 20, and the gas collecting ring 10, the support disk 30, and the heating assembly 40 are disposed inside the reaction chamber 21, with the support disk 30 and the heating assembly 40 located in the middle of the gas collecting ring 10.

[0041] The housing 20 has an openable cover 22 with an air inlet. In this embodiment, the cover 22 has two stacked but non-communicating cavities, each connected to an air inlet and the reaction chamber 21. The two air inlets are used to supply two different reaction gases. An exhaust port is also provided at the bottom of the housing 20.

[0042] A gas collecting ring 10 is disposed within the reaction chamber 21. One end (second end face 102) of the gas collecting ring 10, which has a second gas flow hole 1041, is located at the bottom of the reaction chamber, and the exhaust port on the housing 20 is located on the housing 20 corresponding to the second gas flow hole 1041. The height of the gas collecting ring 10 is equal to or slightly less than the height of the reaction chamber 21, so that when the cover 22 is closed, it can fit as closely as possible to the first end face 101 of the gas collecting ring 10, thereby reducing the flow of reaction gases between the two into the space between the outer surface 104 of the gas collecting ring 10 and the cavity wall of the reaction chamber 21. A mounting cavity 12 is formed in the middle of the inner surface 103 of the gas collecting ring 10. A support disk 30 is rotatably disposed within the mounting cavity 12 for supporting the substrate. In this embodiment, the support disk 30 is a graphite disk, and the surface of the graphite disk is also deposited with an anti-oxidation coating using PECVD, the anti-oxidation coating including a SiC coating.

[0043] Most of the reactant gas entering through the inlet is collected in the mounting cavity 12 by the gas collecting ring 10. Under certain temperature and pressure conditions, a portion of the reactant gas is deposited on the substrate of the support plate 30 after reaction. The gas generated by the reaction and the excess unreacted gas are discharged from the second air flow hole 1041 below the outer surface 104 of the gas collecting ring 10 after passing through the internal cavity of the gas collecting ring 10 through the first air flow hole 1031 on the inner surface 103 of the gas collecting ring 10 and the third air flow hole 1011 on the first end face 101. The aforementioned gas flow pattern reduces the residence time of excess reactive gas in the reaction chamber while continuously injecting reactive gas, shortens the movement path of reactive gas inside the gas collecting ring 10, and lowers the probability of reactive gas diffusing to the areas where the support plate 30 and heating component 40 are located. This prevents other components in the reaction chamber from being oxidized by unreacted reactive gas—oxygen, thereby protecting the support plate 30, heating component 40, and other related components. Furthermore, the reactive gas is discharged from the second airflow hole 1041 below the outer surface 104 of the gas collecting ring 10, which prevents the reactive gas from contacting the cavity wall of the reaction chamber, causing oxidation deposits, and increasing the difficulty and frequency of equipment cleaning.

[0044] A heating assembly 40 is disposed within the mounting cavity 12 and located below the support plate 30. The heating assembly 40 is used to heat the support plate 30. The heating assembly 40 includes a heating plate 41 and heating electrodes. The heating plate 41 is formed by winding a heating wire, which is made of an anti-oxidation material, such as an iron-chromium-aluminum alloy, a nickel-chromium alloy, an iron-chromium-aluminum alloy coated with Al2O3, or a nickel-chromium alloy coated with Al2O3. The heating electrodes are connected to the heating plate 42 and are used to electrically heat the heating plate 42. In this embodiment, the surface of the heating assembly 40 is also deposited with an anti-oxidation coating, which includes a SiC coating.

[0045] Compared with the prior art, the gas collecting ring for gallium oxide epitaxy in the embodiments of the present invention, through the setting of the internal cavity of the gas collecting ring and the air flow holes on the inner and outer surfaces, allows the reaction gas to flow into the internal cavity of the gas collecting ring through the first air flow hole on the inner surface of the gas collecting ring, and then be discharged through the second air flow hole below the outer surface of the gas collecting ring. This reduces the amount of gas inside the mounting cavity where the support plate is located, and also allows the gas to flow out of the mounting cavity and the reaction cavity evenly. At the same time, it reduces the contact deposition of the reaction gas with the inner wall of the reaction cavity and reduces the number of times the reaction cavity needs to be cleaned.

[0046] The gas collecting ring for gallium oxide epitaxy according to embodiments of the present invention can effectively prevent oxidation and extend service life by depositing an anti-oxidation coating.

[0047] The MOCVD equipment for gallium oxide epitaxy according to the present invention reduces the amount of reaction gas flowing into the lower space of the support disk by adjusting the gas collecting ring with a suitable inner diameter and cooperating with a support disk of appropriate size, so that more reaction gas flows out from the second gas flow hole below the gas collecting ring, thereby extending the life of internal metal components and heating components.

[0048] The MOCVD apparatus for gallium oxide epitaxy according to embodiments of the present invention can further prevent the introduced oxygen from oxidizing it by depositing an anti-oxidation coating on the surface of internal components and by changing the material of the heating wire to use an anti-oxidation material.

[0049] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A gas collecting ring for gallium oxide epitaxy, characterized in that, include: The annular body includes a first end face, a second end face, and an inner surface and an outer surface located between the first end face and the second end face. A mounting cavity for accommodating a carrier plate and a heating assembly is formed in the middle of the inner surface. The first end face, the second end face, the inner surface, and the outer surface together enclose a chamber. A plurality of first airflow holes communicating with the chamber are opened on the inner surface, and a plurality of second airflow holes communicating with the chamber are opened on the outer surface. The first airflow holes, the chamber, and the second airflow holes are used to guide the reaction generated gas and excess unreacted reaction gas in the gallium oxide epitaxy process to be discharged from the second airflow holes, reducing contact with the carrier plate and the heating assembly.

2. The gas collecting ring for gallium oxide epitaxy as described in claim 1, characterized in that, Multiple first airflow holes are evenly distributed on the inner surface of the annular body.

3. The gas collecting ring for gallium oxide epitaxy as described in claim 1, characterized in that, Multiple second airflow holes are arranged circumferentially along the annular body, and the distance between the second airflow holes and the second end face is less than the distance between the second airflow holes and the first end face.

4. The gas collecting ring for gallium oxide epitaxy as described in claim 1, characterized in that, The diameter of the first airflow hole and / or the second airflow hole is 2~10mm, and the spacing between adjacent first airflow holes and / or adjacent second airflow holes is 2~10mm.

5. The gas collecting ring for gallium oxide epitaxy as described in claim 4, characterized in that, The diameter of the first airflow hole and / or the second airflow hole is 3~5mm, and the spacing between adjacent first airflow holes and / or adjacent second airflow holes is 3~5mm.

6. The gas collecting ring for gallium oxide epitaxy as described in claim 1, characterized in that, The first end face has a plurality of third airflow holes that communicate with the chamber.

7. The gas collecting ring for gallium oxide epitaxy as described in claim 6, characterized in that, The diameter of the third airflow hole is 2~10mm, and the spacing between adjacent third airflow holes is 2~10mm.

8. The gas collecting ring for gallium oxide epitaxy as described in claim 7, characterized in that, The diameter of the third airflow hole is 3~5mm, and the spacing between adjacent third airflow holes is 3~5mm.

9. The gas collecting ring for gallium oxide epitaxy as described in claim 1, characterized in that, An anti-oxidation coating is deposited on all or part of the first end face, the second end face, the inner surface, and the outer surface.

10. The gas collecting ring for gallium oxide epitaxy as described in claim 1, characterized in that, The straight-line distance between the inner and outer surfaces of the annular body is 5~15mm.

11. An MOCVD apparatus for gallium oxide epitaxy, characterized in that, include: A housing having a reaction chamber inside, and an air inlet and an exhaust outlet provided on the housing; The gas collecting ring for gallium oxide epitaxy as described in any one of claims 1 to 10 is disposed within the reaction chamber, and a mounting cavity is formed in the middle of the gas collecting ring; A support plate, disposed within the mounting cavity, is used to support the substrate; A heating assembly is disposed within the mounting cavity and located below the support plate, the heating assembly being used to heat the support plate.

12. The MOCVD apparatus for gallium oxide epitaxy as described in claim 11, characterized in that, Both the surface of the support plate and the surface of the heating component are coated with an anti-oxidation coating.

13. The MOCVD apparatus for gallium oxide epitaxy as described in claim 11, characterized in that, The heating assembly includes a heating plate, which is formed by winding a heating wire. The heating wire is an iron-chromium-aluminum alloy, a nickel-chromium alloy, an iron-chromium-aluminum alloy with Al2O3 coating, or a nickel-chromium alloy with Al2O3 coating.

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