Epitaxial growth method of gallium oxide material, gallium oxide epitaxial structure and ultraviolet detector

Abstract

The invention relates to an epitaxial growth method of a gallium oxide material, a gallium oxide epitaxial structure and an ultraviolet detector. The epitaxial growth method of the gallium oxide material comprises the following steps: providing a substrate; forming an aluminum nitride layer on the substrate; epitaxially growing at least one composite interface layer on the aluminum nitride layer, wherein the composite interface layer comprises an aluminum oxide layer and an indium oxide layer which are stacked in sequence; and epitaxially growing a gallium oxide layer on the composite interface layer. Therefore, the dislocation density and thermal stress in the gallium oxide layer can be reduced, and the quality and performance of the gallium oxide epitaxial structure can be improved. When the prepared gallium oxide epitaxial structure is applied to a photoelectric detector, the performance and the reliability of the device can be remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular, to a method for epitaxial growth of gallium oxide material, a gallium oxide epitaxial structure, and an ultraviolet detection device. Background Art

[0002] Ultraviolet detection technology has a wide range of applications in the fields of environmental monitoring, solar-blind imaging, flame detection, missile warning, secure communication, biomedicine, etc. In particular, ultraviolet detection devices operating in the solar-blind band (200 nm - 280 nm) are hardly interfered by solar background radiation, and have advantages such as strong anti-interference ability, high sensitivity, and low background noise, and thus have more important application prospects.

[0003] Gallium oxide has shown significant advantages in the fields of power electronic devices and ultraviolet optoelectronic devices due to its ultra-wide bandgap width (4.8 eV - 4.9 eV), high breakdown field strength (8 MV·cm -1 ), and relatively high Baliga figure of merit. Since the bandgap width of gallium oxide is well matched with the solar-blind ultraviolet band, gallium oxide is very suitable for application in solar-blind ultraviolet detection devices.

[0004] Currently, gallium oxide is usually obtained by epitaxially growing gallium oxide material on a substrate. However, there are problems such as lattice mismatch and differences in thermal expansion coefficients in the heteroepitaxial growth of gallium oxide material. The prepared gallium oxide thin film is prone to have a high dislocation density and thermal stress, which seriously affects the performance and reliability of the devices prepared using the gallium oxide thin film and hinders the industrialization process of gallium oxide devices. Summary of the Invention

[0005] In view of this, embodiments of the present application provide a method for epitaxial growth of gallium oxide material, a gallium oxide epitaxial structure, and an ultraviolet detection device to solve at least one problem in the background art.

[0006] In a first aspect, embodiments of the present application provide a method for epitaxial growth of gallium oxide material, the method comprising: providing a substrate; forming an aluminum nitride layer on the substrate; epitaxially growing at least one composite interface layer on the aluminum nitride layer, the composite interface layer comprising an aluminum oxide layer and an indium oxide layer stacked in sequence; epitaxially growing a gallium oxide layer on the composite interface layer.

[0007] In combination with the first aspect of the present application, in an optional embodiment, epitaxially growing the composite interface layer comprises: introducing a first aluminum source and a first oxygen source to epitaxially grow the aluminum oxide layer; when epitaxially growing the aluminum oxide layer, at least one of the following conditions is satisfied: (1) The temperature of the epitaxial growth is 600°C to 800°C; (2) The pressure of the epitaxial growth is 20 mbar to 150 mbar; (3) The flow rate of the first aluminum source is greater than or equal to 5 sccm and less than or equal to 20 sccm; (4) The flow rate of the first oxygen source is greater than 0 sccm and less than or equal to 100 sccm; (5) The time of the epitaxial growth is 1 s to 5 s.

[0008] Combining with the first aspect of the present application, in an alternative embodiment, the epitaxial growth of the composite interface layer further includes: Introducing an indium source and a second oxygen source, and epitaxially growing the indium oxide layer on the aluminum oxide layer; the epitaxial growth of the indium oxide layer satisfies at least one of the following conditions: (1) The temperature of the epitaxial growth is 600°C to 800°C; (2) The pressure of the epitaxial growth is 20 mbar to 150 mbar; (3) The flow rate of the indium source is greater than or equal to 5 sccm and less than or equal to 20 sccm; (4) The flow rate of the second oxygen source is greater than 0 sccm and less than or equal to 100 sccm; (5) The time of the epitaxial growth is 1 s to 10 s.

[0009] Combining with the first aspect of the present application, in an alternative embodiment, before epitaxially growing at least one layer of the composite interface layer on the aluminum nitride layer, the method further includes: Introducing a second aluminum source, a gallium source and a nitrogen source, and epitaxially growing an Al x Ga 1-x N layer on the aluminum nitride layer, where 0.2 ≤ x ≤ 0.5; the epitaxial growth of the Al x Ga 1-x N layer satisfies at least one of the following conditions: (1) The temperature of the epitaxial growth is 1000°C to 1200°C; (2) The pressure of the epitaxial growth is 50 mbar to 100 mbar; (3) The flow rate of the second aluminum source is greater than or equal to 50 sccm and less than or equal to 300 sccm; (4) The flow rate of the gallium source is greater than or equal to 20 sccm and less than or equal to 100 sccm; (5) The flow rate of the nitrogen source is greater than or equal to 0.5 slm and less than or equal to 2 slm; (6) The thickness of the Al x Ga 1-x N layer is 5 nm to 30 nm.

[0010] In combination with the first aspect of the present application, in an alternative embodiment, before epitaxially growing the gallium oxide layer on the composite interface layer, the method further includes: Performing heat treatment on the composite interface layer; the heat treatment satisfies at least one of the following conditions: (1) The temperature of the heat treatment is 1000 °C to 1400 °C; (2) The time of the heat treatment is 10 min to 30 min; (3) The heat treatment is performed in an atmosphere including hydrogen.

[0011] In combination with the first aspect of the present application, in an alternative embodiment, the method satisfies at least one of the following conditions: (1) The thickness of the composite interface layer is 1 nm to 5 nm; (2) The thickness of the aluminum oxide layer is 0.5 nm to 3 nm; (3) The thickness of the indium oxide layer is 0.5 nm to 2 nm; (4) The thickness of the aluminum nitride layer is 5 nm to 50 nm; (5) The thickness of the gallium oxide layer is 500 nm to 2500 nm; (6) The number of layers of the composite interface layer is greater than or equal to 2, and each of the composite interface layers is the same.

[0012] In a second aspect, an embodiment of the present application provides a gallium oxide epitaxial structure, including: A substrate; An aluminum nitride layer located on the substrate; At least one composite interface layer located on the aluminum nitride layer, the composite interface layer including an aluminum oxide layer and an indium oxide layer stacked in sequence; A gallium oxide layer located on the composite interface layer.

[0013] In combination with the second aspect of the present application, in an alternative embodiment, the gallium oxide epitaxial structure satisfies at least one of the following conditions: (1) The thickness of the composite interface layer is 1 nm to 5 nm; (2) The thickness of the aluminum oxide layer is 0.5 nm to 3 nm; (3) The thickness of the indium oxide layer is 0.5 nm to 2 nm; (4) The thickness of the aluminum nitride layer is 5 nm to 50 nm; (5) The thickness of the gallium oxide layer is 500 nm to 2500 nm; (6) The number of layers of the composite interface layer is greater than or equal to 2, and each of the composite interface layers is the same.

[0014] Combined with the second aspect of the present application, in an optional embodiment, the gallium oxide epitaxial structure further includes an Al x Ga 1-x N layer located between the aluminum nitride layer and the composite interface layer, where 0.2 ≤ x ≤ 0.5.

[0015] In a third aspect, an embodiment of the present application provides an ultraviolet detection device, including the gallium oxide epitaxial structure prepared by the epitaxial growth method of the gallium oxide material according to any item of the first aspect or including the gallium oxide epitaxial structure according to any item of the second aspect.

[0016] Compared with the prior art, the embodiments of the present application have the following beneficial effects: The epitaxial growth method of the gallium oxide material, the gallium oxide epitaxial structure, and the ultraviolet detection device provided by the embodiments of the present application. The epitaxial growth method of the gallium oxide material includes: providing a substrate; forming an aluminum nitride layer on the substrate; epitaxially growing at least one composite interface layer on the aluminum nitride layer, and the composite interface layer includes an aluminum oxide layer and an indium oxide layer stacked in sequence; and epitaxially growing a gallium oxide layer on the composite interface layer. In the embodiments of the present application, first, an aluminum nitride layer is formed on the substrate, and the aluminum nitride layer can improve the lattice mismatch problem between the substrate and the subsequently epitaxially grown composite interface layer, which is beneficial to ensuring the high-quality growth of the composite interface layer; next, at least one composite interface layer is epitaxially grown on the aluminum nitride layer, and the composite interface layer is composed of an aluminum oxide layer and an indium oxide layer stacked in sequence, which has the functions of blocking the diffusion of defects, forming low interface states, and reducing phonon scattering, which is beneficial to forming better interface heat transfer, reducing the generation of thermal stress and the proliferation of defects caused by thermal stress, so as to be able to reduce the dislocation density and thermal stress in the gallium oxide layer epitaxially grown on the composite interface layer, and further improve the quality and performance of the gallium oxide epitaxial structure. When the prepared gallium oxide epitaxial structure is applied to a photoelectric detection device, the performance and reliability of the device can be significantly improved.

[0017] The additional aspects and advantages of the present application will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present application. Description of the Drawings

[0018] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation to the present application. In the drawings: Figure 1 It is a schematic flow chart of the epitaxial growth method of the gallium oxide material provided by the embodiment of the present application; Figures 2 to 6Schematic cross-sectional structure diagram of the epitaxial structure during the growth of the gallium oxide material epitaxial growth method provided by the embodiments of the present application; Figure 7 Atomic force microscope image of the surface of the gallium oxide epitaxial structure prepared in Example 1; Figure 8 Atomic force microscope image of the surface of the gallium oxide epitaxial structure prepared in Comparative Example 1. Detailed implementation manners

[0019] The exemplary embodiments disclosed in the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the specific embodiments set forth herein. On the contrary, these embodiments are provided so that the present application can be more thoroughly understood and the scope of the present application disclosed can be fully conveyed to those skilled in the art.

[0020] In the following description, numerous specific details are given to provide a more thorough understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some well-known technical features are not described; that is, not all features of the actual embodiments are described here, and the well-known functions and structures are not described in detail.

[0021] In the drawings, for clarity, the dimensions of layers, regions, elements and their relative dimensions may be exaggerated. The same reference numerals throughout the drawings denote the same elements.

[0022] When an element or layer is referred to as "on...", "adjacent to...", "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected or coupled to the other element or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as "directly on...", "directly adjacent to...", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers. Although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below may be denoted as the second element, component, region, layer or part. And when discussing the second element, component, region, layer or part, it does not indicate that the present application necessarily has a first element, component, region, layer or part.

[0023] Spatial relationship terms such as "under", "below", "beneath", "underneath", "above", "over", etc. may be used herein for convenience of description to describe the relationship of one element or feature shown in the figures with other elements or features. In addition to the orientations shown in the figures, the spatial relationship terms are also intended to include different orientations of the device in use and operation. For example, if the device in the attached drawings is flipped, then an element or feature described as "under other elements" or "beneath them" or "under it" will be oriented "above" the other elements or features. Thus, the exemplary terms "under" and "beneath" can include both the upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are to be interpreted accordingly.

[0024] The purpose of the terms used herein is only to describe specific embodiments and is not a limitation of the present application. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. The terms "comprising" and / or "including", when used in this specification, identify the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups. As used herein, the term "and / or" includes any and all combinations of the related listed items.

[0025] To thoroughly understand the present application, detailed steps and detailed structures will be presented in the following description to illustrate the technical solutions of the present application. The preferred embodiments of the present application are described in detail below. However, in addition to these detailed descriptions, the present application may have other embodiments.

[0026] Based on this, an embodiment of the present application provides a method for epitaxial growth of gallium oxide material. Figure 1 It is a schematic flow chart of the method for epitaxial growth of gallium oxide material provided by the embodiment of the present application; as Figure 1 shown, the method includes: Step S1, providing a substrate; Step S2, forming an aluminum nitride layer on the substrate; Step S3, epitaxially growing at least one composite interface layer on the aluminum nitride layer, the composite interface layer including an aluminum oxide layer and an indium oxide layer stacked in sequence; Step S4, epitaxially growing a gallium oxide layer on the composite interface layer.

[0027] It can be understood that through the above method, first, an aluminum nitride layer is formed on the substrate. The aluminum nitride layer can improve the lattice mismatch problem between the substrate and the subsequent epitaxially grown composite interface layer, which is beneficial to ensuring the high-quality growth of the composite interface layer. Next, at least one composite interface layer is epitaxially grown on the aluminum nitride layer. The composite interface layer is composed of an aluminum oxide layer and an indium oxide layer stacked in sequence, which has the functions of blocking the diffusion of defects, forming low interface states, and reducing phonon scattering, and is beneficial to forming better interface heat transfer, reducing the generation of thermal stress and the defect proliferation caused by thermal stress. Therefore, the dislocation density and thermal stress in the gallium oxide layer epitaxially grown on the composite interface layer can be reduced, and further the quality and performance of the obtained gallium oxide epitaxial structure can be improved. When the obtained gallium oxide epitaxial structure is applied to a photodetector device, the performance and reliability of the device can be significantly improved.

[0028] Next, in conjunction with Figures 2 to 6 , the epitaxial growth method of the gallium oxide material provided by the embodiments of the present application, the gallium oxide epitaxial structure, and the corresponding beneficial effects will be further described in detail.

[0029] First, please refer to Figure 2 , and perform step S1 to provide a substrate 100.

[0030] Here, the substrate 100 may include, for example, a sapphire substrate, a silicon substrate, a silicon carbide substrate, an Al2O3 / AlN composite substrate, a Si / AlN composite substrate, or a SiC / AlN composite substrate, etc. In a specific embodiment, the substrate 100 is a sapphire substrate or a silicon substrate.

[0031] Next, please refer to Figure 3 , and perform step S2 to form an aluminum nitride layer 200 on the substrate 100. In this way, the lattice mismatch and interface stress problems between the substrate 100 and the subsequent epitaxially grown composite interface layer can be improved, which is beneficial to ensuring the high-quality growth of the composite interface layer, and further improving the quality of the subsequently grown gallium oxide layer.

[0032] In the actual preparation process, for example, at least one of a physical vapor deposition process (specifically, magnetron sputtering), a chemical vapor deposition process (specifically, metalorganic chemical vapor deposition), and an atomic layer deposition process can be used to form the aluminum nitride layer 200.

[0033] In some embodiments, a magnetron sputtering process can be used to form the aluminum nitride layer 200 on the substrate 100. Using the magnetron sputtering process to form the aluminum nitride layer 200 has stronger process controllability compared to heteroepitaxially growing the aluminum nitride layer 200 on the substrate 100, and is convenient to form a higher-quality aluminum nitride layer 200 on the substrate 100.

[0034] Specifically, the temperature of magnetron sputtering can be 200°C to 800°C; the power can be 20 W to 200 W; the flow rate of nitrogen can be greater than 0 sccm and less than or equal to 200 sccm; the flow rate of oxygen can be greater than 0 sccm and less than or equal to 1 sccm; the flow rate of the carrier gas (specifically, argon for example) can be greater than 0 sccm and less than or equal to 200 sccm; the time of magnetron sputtering can be 10 s to 100 s. Meeting at least one of the above conditions is beneficial to preparing the aluminum nitride layer 200 with higher quality.

[0035] In some embodiments, the thickness of the aluminum nitride layer 200 can be 5 nm to 50 nm, for example, it can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm or any value between any two of the above numerical ranges. In this way, not only can the lattice mismatch and interface stress problems between the substrate 100 and the subsequent epitaxially grown composite interface layer be better improved, which is beneficial to ensuring the high-quality growth of the composite interface layer, but also the problems such as the influence on carrier transport that may be caused by the over-thick aluminum nitride layer 200 can be avoided.

[0036] In some embodiments, after the aluminum nitride layer 200 is formed on the substrate 100, the epitaxial growth method of the gallium oxide material may further include: performing high-temperature annealing on the aluminum nitride layer 200. In this way, the interface quality between the aluminum nitride layer 200 and the substrate 100 can be improved, and it is beneficial to the subsequent epitaxial growth of a high-quality film layer on the aluminum nitride layer 200.

[0037] In the actual preparation process, for example, high-temperature annealing can be performed in an inert gas (specifically, nitrogen for example) atmosphere. Specifically, the high-temperature annealing temperature can be 1600°C to 1700°C; the high-temperature annealing time can be 30 min to 60 min.

[0038] In some embodiments, please refer to Figure 4 , before epitaxially growing at least one composite interface layer on the aluminum nitride layer 200, the epitaxial growth method of the gallium oxide material may further include: introducing a second aluminum source, a gallium source, and a nitrogen source, and epitaxially growing an Al x Ga 1-x N layer 300 on the aluminum nitride layer 200, where 0.2 ≤ x ≤ 0.5.

[0039] In the embodiments of the present application, when epitaxially growing an Al x Ga 1-x N layer 300 on the aluminum nitride layer 200, Al x Ga 1-xThe lattice matching degree between the N-layer 300 and the subsequently grown composite interface layer is higher. Thus, it is beneficial to the high-quality growth of the subsequent composite interface layer, reduce defects such as dislocations and interface stress at the epitaxial layer interface, and further improve the quality and performance of the finally obtained gallium oxide epitaxial structure.

[0040] Specifically, during the epitaxial growth of the Al x Ga 1-x N-layer 300, the epitaxial growth temperature can be 1000°C to 1200°C. The epitaxial growth pressure can be 50 mbar to 100 mbar. The flow rate of the second aluminum source can be greater than or equal to 50 sccm and less than or equal to 350 sccm, and further optionally greater than or equal to 80 sccm and less than or equal to 300 sccm. The flow rate of the gallium source can be greater than or equal to 20 sccm and less than or equal to 35 sccm. The flow rate of the nitrogen source can be greater than or equal to 0.5 slm and less than or equal to 2 slm. Meeting at least one of the above conditions is beneficial to the formation of an Al x Ga 1-x N-layer 300 with higher quality and appropriate Al composition.

[0041] Among them, the second aluminum source can include, for example, trimethylaluminum (TMAl). The gallium source can include, for example, triethylgallium (TEGa) and / or trimethylgallium (TMGa). The nitrogen source can include, for example, ammonia (NH3).

[0042] In some embodiments, element doping can also be performed during the epitaxial growth of the Al x Ga 1-x N-layer 300 to form an n-type Al x Ga 1-x N-layer.

[0043] Exemplarily, a silicon source (specifically, silane for example) can be introduced during the epitaxial growth of the Al x Ga 1-x N-layer 300 to form an n-type Al x Ga 1-x N-layer. Among them, in the n-type Al x Ga 1-x N-layer, the doping concentration of Si can be greater than or equal to 1E17 atoms / cm³.

[0044] In some embodiments, the thickness of the Al x Ga 1-x N-layer 300 can be 5 nm to 30 nm, for example, it can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm or any value between any two of the above numerical ranges. Thus, not only can the Al x Ga 1-xThe lattice matching degree between the N-layer 300 and the composite interface layer is higher, and it can also avoid the problems such as carrier transport caused by the excessive thickness of the Al x Ga 1-x N-layer 300.

[0045] Next, please refer to Figure 5 , and perform step S3 to epitaxially grow at least one composite interface layer 400 on the aluminum nitride layer 200. The composite interface layer 400 includes an aluminum oxide layer 401 and an indium oxide layer 402 stacked in sequence.

[0046] In the embodiment of the present application, at least one composite interface layer 400 epitaxially grown on the aluminum nitride layer 200 has the following functions: First, blocking defect diffusion; the composite interface layer 400 can effectively block the diffusion of defects from the underlying heteroepitaxy upward. In heteroepitaxy, due to lattice mismatch, a large number of defects will inevitably be generated at the interface. These defects caused by high interface traps as recombination centers and generation centers will seriously affect the carrier transport at the interface, shorten the carrier lifetime, and increase the dark current of the photodetector device. The composite interface layer 400 can not only block the diffusion of defects, but also play a buffering role under thermal stress, thereby improving the interface quality and reducing the dislocation density and thermal stress in the subsequent epitaxially grown film layer. Second, forming a low interface state; the composite interface layer 400 can form an interface with a low state density at the interface, having a sufficiently low density of recombination centers and generation centers on the interface, reducing the interface state density, and passivating the surface, so that electrons and holes can pass through with minimal loss. Third, reducing phonon scattering; the composite interface layer 400 can enhance the interaction between interface atoms, weaken phonon mismatch, reduce phonon scattering, and thus enhance the thermal transport of the device, reduce the generation of thermal stress, and further inhibit the rapid proliferation of defects caused by thermal stress. Therefore, by epitaxially growing at least one composite interface layer 400, the quality and performance of the gallium oxide epitaxial structure can be significantly improved.

[0047] It should be noted that Figure 5 shows the situation where an Al x Ga 1-x N-layer 300 has been epitaxially grown on the aluminum nitride layer 200 before the epitaxial growth of the composite interface layer 400, that is, the composite interface layer 400 is epitaxially grown on the surface of the Al x Ga 1-x N-layer 300. Of course, in some other embodiments of the present application, the composite interface layer 400 can also be epitaxially grown on the surface of the aluminum nitride layer 200.

[0048] In some embodiments, please continue to refer to Figure 5, the epitaxial growth composite interface layer 400 may include: First, a first aluminum source and a first oxygen source are introduced to epitaxially grow an aluminum oxide layer 401; then, an indium source and a second oxygen source are introduced to epitaxially grow an indium oxide layer 402 on the aluminum oxide layer 401.

[0049] Specifically, during the process of epitaxially growing the aluminum oxide layer 401, the epitaxial growth temperature may be 600°C to 800°C, for example, it may be 600°C, 700°C, 800°C, or any value between any two of the above numerical ranges. The epitaxial growth pressure may be 20 mbar to 150 mbar, for example, it may be 20 mbar, 50 mbar, 80 mbar, 110 mbar, 130 mbar, 150 mbar, or any value between any two of the above numerical ranges. The flow rate of the first aluminum source may be greater than or equal to 5 sccm and less than or equal to 20 sccm, for example, it may be 5 sccm, 10 sccm, 15 sccm, 20 sccm, or any value between any two of the above numerical ranges. The flow rate of the first oxygen source may be greater than 0 sccm and less than or equal to 100 sccm, for example, it may be 10 sccm, 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, 100 sccm, or any value between any two of the above numerical ranges. The epitaxial growth time may be 1 s to 5 s, for example, it may be 1 s, 2 s, 3 s, 4 s, 5 s, or any value between any two of the above numerical ranges. Meeting at least one of the above conditions is beneficial to forming an aluminum oxide layer 401 with higher quality and appropriate thickness. Exemplarily, the first aluminum source may include trimethylaluminum (TMAl). The first oxygen source may include oxygen.

[0050] Specifically, during the process of epitaxially growing the indium oxide layer 402, the epitaxial growth temperature can be 600°C to 800°C, for example, it can be 600°C, 700°C, 800°C, or any value between any two of the above numerical ranges. The epitaxial growth pressure can be 20 mbar to 150 mbar, for example, it can be 20 mbar, 50 mbar, 80 mbar, 110 mbar, 130 mbar, 150 mbar, or any value between any two of the above numerical ranges. The flow rate of the indium source can be greater than or equal to 5 sccm and less than or equal to 20 sccm, for example, it can be 5 sccm, 10 sccm, 15 sccm, 20 sccm, or any value between any two of the above numerical ranges. The flow rate of the second oxygen source can be greater than 0 sccm and less than or equal to 100 sccm, for example, it can be 10 sccm, 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, 100 sccm, or any value between any two of the above numerical ranges. Meeting at least one of the above conditions is beneficial to forming an indium oxide layer 402 with higher quality and appropriate thickness. Exemplarily, the indium source can include trimethylindium (TMIn). The second oxygen source can include oxygen.

[0051] In the actual preparation process, the temperatures and pressures of epitaxially growing the aluminum oxide layer 401 and the indium oxide layer 402 can be the same or different. The types and flow rates of the first oxygen source and the second oxygen source can be the same or different. In a specific embodiment, at least one of the temperatures and pressures of epitaxially growing the aluminum oxide layer 401 and the indium oxide layer 402 is the same. In this way, when switching between the epitaxial growth of the aluminum oxide layer 401 and the indium oxide layer 402, there is no need to adjust the temperature and / or pressure again, which can simplify the process and improve the efficiency. Further, the types and flow rates of the first oxygen source and the second oxygen source are the same. In this way, when switching between the epitaxial growth of the aluminum oxide layer 401 and the indium oxide layer 402, there is no need to switch and adjust the oxygen source, which can further simplify the process and improve the efficiency. In a more specific embodiment, the temperatures and pressures of epitaxially growing the aluminum oxide layer 401 and the indium oxide layer 402 are the same, and the types and flow rates of the first oxygen source and the second oxygen source are the same. In this way, when switching between the epitaxial growth of the aluminum oxide layer 401 and the indium oxide layer 402, only the aluminum source and the indium source need to be switched, making the process simpler, the epitaxial growth efficiency higher, and the quality of the epitaxial layer more uniform and stable.

[0052] It can be understood that in the above embodiments, only the steps of epitaxially growing a single layer of the composite interface layer 400 are given by way of example. In some specific embodiments, the number of layers of the composite interface layer 400 can be greater than or equal to 2. When epitaxially growing multiple layers of the composite interface layer 400, the steps of epitaxially growing the aluminum oxide layer 401 and the indium oxide layer 402 in the above embodiments can be alternated (which can be referred to as the growth of a superlattice cyclic structure). For example, first, the aluminum oxide layer 401 is epitaxially grown, then the indium oxide layer 402 is epitaxially grown on the aluminum oxide layer 401, then the aluminum oxide layer 401 is epitaxially grown on the indium oxide layer 402, and then the indium oxide layer 402 is epitaxially grown on the aluminum oxide layer 401 again... until the composite interface layer 400 with the target number of layers is epitaxially grown. That is, in the formed multiple layers of the composite interface layer 400, the aluminum oxide layer 401 and the indium oxide layer 402 are arranged alternately in sequence. Further, when the number of layers of the composite interface layer 400 is greater than or equal to 2, each composite interface layer 400 can be the same. In this way, not only can the preparation process be simplified, but also the quality and performance of the multiple layers of the composite interface layer 400 can be made more uniform and stable, which is beneficial to improving the quality and performance of the finally obtained gallium oxide epitaxial structure.

[0053] When the thickness of the composite interface layer 400 is too thin, it may affect its function of blocking the diffusion of defects, forming low interface states, and reducing phonon scattering; when the thickness of the composite interface layer 400 is too thick, it will extend the carrier transmission path and affect the thermal conductivity, and may generate thermal stress, which further leads to the proliferation of defects. Therefore, in some embodiments, the thickness of the composite interface layer 400 can be 1 nm to 5 nm, for example, it can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, or any value between any two of the above numerical ranges. Controlling the thickness of the composite interface layer 400 within the above range is beneficial to giving full play to the function of the composite interface layer 400, better reducing the dislocation density and thermal stress in the subsequently obtained gallium oxide layer, and thus improving the quality and performance of the gallium oxide epitaxial structure.

[0054] In some embodiments, the thickness of the aluminum oxide layer 401 can be 0.5 nm to 3 nm, for example, it can be 0.5 nm, 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, or any value between any two of the above numerical ranges. In this way, it is beneficial to control the thickness of the composite interface layer 400 within a suitable range.

[0055] In some embodiments, the thickness of the indium oxide layer 402 can be 0.5 nm to 2 nm, for example, it can be 0.5 nm, 1 nm, 1.5 nm, 2 nm, or any value between any two of the above numerical ranges. In this way, it is beneficial to control the thickness of the composite interface layer 400 within a suitable range.

[0056] In some embodiments, after the epitaxial growth of the composite interface layer 400 and before the epitaxial growth of the gallium oxide layer on the composite interface layer 400, the epitaxial growth method of the gallium oxide material may further include: performing a heat treatment on the composite interface layer 400. Through the heat treatment (specifically, for example, annealing treatment), it is beneficial to the covalent bonding between the atoms at the film layer interface, and thus better interface heat transfer can be formed.

[0057] In the actual preparation process, the temperature of the heat treatment can be 1000°C to 1400°C, for example, it can be 1000°C, 1100°C, 1200°C, 1300°C, 1400°C or any value between any two of the above numerical ranges. The time of the heat treatment can be 10 min to 30 min, for example, it can be 10 min, 20 min, 30 min or any value between any two of the above numerical ranges. Controlling the temperature and / or time of the heat treatment within the above ranges is beneficial to improving the effect of the heat treatment, effectively promoting the covalent bonding between the interface atoms, forming better interface heat transfer, and at the same time avoiding affecting the composite interface layer 400.

[0058] Furthermore, the heat treatment can be carried out in an atmosphere including hydrogen. In this way, the effect and efficiency of the heat treatment can be improved. For example, the heat treatment can be carried out in a hydrogen atmosphere, and the flow rate of hydrogen can be 80 slm to 120 slm.

[0059] Finally, please refer to Figure 6 and perform step S4 to epitaxially grow the gallium oxide layer 500 on the composite interface layer 400.

[0060] In the embodiments of the present application, since at least one composite interface layer 400 has been epitaxially grown before the epitaxial growth of the gallium oxide layer 500, by utilizing the functions of the composite interface layer 400 to block defect diffusion, form low interface states, and reduce phonon scattering, it is beneficial to form better interface heat transfer, reduce thermal stress and the resulting defect proliferation. Therefore, the dislocation density and thermal stress in the gallium oxide layer 500 can be significantly reduced, and the quality and performance of the gallium oxide layer 500 can be improved.

[0061] In the actual preparation process, a second gallium source and a third oxygen source can be introduced to epitaxially grow the gallium oxide layer 500. Specifically, the gallium oxide layer 500 can be grown under the conditions of a temperature of 800°C to 1200°C, a pressure of 50 mbar to 100 mbar, a flow rate of the second gallium source of 50 sccm to 500 sccm, and a flow rate of the third oxygen source of 50 sccm to 100 sccm.

[0062] In some embodiments, element doping can also be performed during the epitaxial growth of the gallium oxide layer 500 to form a p-type or n-type gallium oxide layer 500.

[0063] Exemplarily, a silicon source (specifically, silane for example) can be introduced during the epitaxial growth of the gallium oxide layer 500 to form an n-type gallium oxide layer. Among them, in the n-type gallium oxide layer, the doping concentration of Si can be between 1E17 atoms / cm³ and 1E19 atoms / cm³.

[0064] In some embodiments, the thickness of the gallium oxide layer 500 can be 500 nm to 2500 nm. In this way, the requirements for preparing various types of gallium oxide devices can be met.

[0065] The embodiment of the present application also provides a gallium oxide epitaxial structure, as Figure 6 shown. This gallium oxide epitaxial structure includes: a substrate 100; an aluminum nitride layer 200 located on the substrate 100; at least one composite interface layer 400 located on the aluminum nitride layer 200, and the composite interface layer 400 includes an aluminum oxide layer 401 and an indium oxide layer 402 stacked in sequence; a gallium oxide layer 500 located on the composite interface layer 400.

[0066] In the embodiment of the present application, an aluminum nitride layer 200 is provided between the substrate 100 and the composite interface layer 400. The aluminum nitride layer 200 can improve the lattice mismatch problem between the substrate 100 and the composite interface layer 400, and can reduce interface defects and interface stress. In the actual preparation process, it is beneficial to grow a high-quality composite interface layer 400; at least one composite interface layer 400 is provided between the aluminum nitride layer 200 and the gallium oxide layer 500. The composite interface layer 400 is composed of an aluminum oxide layer 401 and an indium oxide layer 402 stacked in sequence, and has the functions of blocking defect diffusion, forming low interface states, and reducing phonon scattering, which is beneficial to forming better interface heat transfer, reducing the generation of thermal stress and the defect proliferation caused by thermal stress, so as to reduce the dislocation density and thermal stress in the gallium oxide layer 500, and further improve the quality and performance of the gallium oxide epitaxial structure. When the prepared gallium oxide epitaxial structure is applied to a photodetector device, the performance and reliability of the device can be significantly improved.

[0067] In some embodiments, the thickness of the aluminum nitride layer 200 can be 5 nm to 50 nm, for example, it can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm or any value between any two of the above numerical ranges. In this way, not only can the lattice mismatch and interface stress problems between the substrate 100 and the composite interface layer 400 be better improved, which is beneficial to improving the quality of the composite interface layer 400, but also the problems such as the influence on carrier transport that may be caused by too thick aluminum nitride layer 200 can be avoided.

[0068] In the embodiments of the present application, at least one composite interface layer 400 has the following functions: First, blocking the diffusion of defects; the composite interface layer 400 can effectively block the defects from the underlying heteroepitaxy from diffusing upward. In heteroepitaxy, due to lattice mismatch, a large number of defects will inevitably be generated at the interface. The high interface traps caused by these defects, as recombination centers and generation centers, will seriously affect the carrier transport at the interface, shorten the carrier lifetime, and increase the dark current of the photodetector device. The composite interface layer 400 can not only block the diffusion of defects, but also play a buffering role under thermal stress, thereby improving the interface quality and reducing the dislocation density and thermal stress in the subsequent epitaxial growth film layer. Second, forming low interface states; the composite interface layer 400 can form an interface with a low state density at the interface, having a sufficiently low density of recombination centers and generation centers on the interface, reducing the interface state density, and passivating the surface, so that electrons and holes can pass through with minimal loss. Third, reducing phonon scattering; the composite interface layer 400 can enhance the interaction between interface atoms, weaken phonon mismatch, reduce phonon scattering, thereby enhancing the thermal transport of the device, reducing the generation of thermal stress, and further suppressing the rapid proliferation of defects caused by thermal stress. Therefore, by epitaxially growing at least one composite interface layer 400, the quality and performance of the gallium oxide epitaxial structure can be significantly improved.

[0069] It can be understood that Figure 6 only the case where the gallium oxide epitaxial structure includes one composite interface layer 400 is exemplarily shown. In some specific embodiments, the number of layers of the composite interface layer 400 can be greater than or equal to 2. In the multi-layer composite interface layer 400, the alumina layer 401 and the indium oxide layer 402 are arranged alternately in sequence. Further, when the number of layers of the composite interface layer 400 is greater than or equal to 2, each composite interface layer 400 can be the same. In this way, not only can the actual preparation process be simplified, but also the quality and performance of the multi-layer composite interface layer 400 can be more uniform and stable, which is beneficial to improving the quality and performance of the gallium oxide epitaxial structure.

[0070] In some embodiments, the thickness of the composite interface layer 400 can be 1 nm to 5 nm, for example, it can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, or any value between any two of the above numerical ranges. Controlling the thickness of the composite interface layer 400 within the above range is beneficial to giving full play to the role of the composite interface layer 400, better reducing the dislocation density and thermal stress in the gallium oxide layer 500, and further improving the quality and performance of the gallium oxide epitaxial structure.

[0071] In some embodiments, the thickness of the alumina layer 401 can be 0.5 nm to 3 nm, for example, it can be 0.5 nm, 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, or any value between any two of the above numerical ranges. In this way, it is beneficial to control the thickness of the composite interface layer 400 within a suitable range.

[0072] In some embodiments, the thickness of the indium oxide layer 402 may be 0.5 nm to 2 nm, for example, it may be 0.5 nm, 1 nm, 1.5 nm, 2 nm, or any value between any two of the above numerical ranges. Thus, it is beneficial to control the thickness of the composite interface layer 400 within a suitable range.

[0073] In some embodiments, the thickness of the gallium oxide layer 500 may be 500 nm to 2500 nm. Thus, it can meet the requirements for fabricating various types of gallium oxide devices.

[0074] In the embodiments of the present application, the conductivity type of the gallium oxide layer 500 may be p-type or n-type. In some specific embodiments, the conductivity type of the gallium oxide layer 500 is n-type. Exemplarily, the n-type gallium oxide layer may contain a doping element Si, wherein the doping concentration of Si may be between 1E17 atoms / cm³ and 1E19 atoms / cm³.

[0075] In some embodiments, please continue to refer to Figure 6 , the gallium oxide epitaxial structure may further include: an Al x Ga 1-x N layer 300 located between the aluminum nitride layer 200 and the composite interface layer 400, where 0.2 ≤ x ≤ 0.5.

[0076] In the embodiments of the present application, by providing an Al x Ga 1-x N layer 300 between the aluminum nitride layer 200 and the composite interface layer 400, since the lattice matching degree between the Al x Ga 1-x N layer 300 and the composite interface layer 400 is higher, it is possible to reduce defects such as dislocations and interface stress at the epitaxial layer interface, and thus improve the quality of the composite interface layer 400 and the overall quality and performance of the gallium oxide epitaxial structure.

[0077] Al x Ga 1-x The conductivity type of the N layer 300 may be n-type. Exemplarily, the n-type Al x Ga 1-x N layer may contain a doping element Si, wherein the doping concentration of Si may be greater than or equal to 1E17 atoms / cm³.

[0078] In some embodiments, the thickness of the Al x Ga 1-x N layer 300 may be 5 nm to 30 nm, for example, it may be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, or any value between any two of the above numerical ranges. Thus, not only can the Alx Ga 1-x The lattice matching degree between the GaN layer 300 and the composite interface layer 400 is higher, and it can also avoid the problems such as carrier transport caused by the excessive thickness of the AlGaN layer 300. x Ga 1-x The excessive thickness of the GaN layer 300 may cause problems such as affecting carrier transport.

[0079] The embodiment of the present application also provides an ultraviolet detection device, which includes a gallium oxide epitaxial structure prepared by the epitaxial growth method of the gallium oxide material in any of the foregoing embodiments or includes the gallium oxide epitaxial structure in any of the foregoing embodiments.

[0080] The ultraviolet detection device here can be, for example, a solar-blind ultraviolet detection device, etc. In the ultraviolet detection device, the gallium oxide layer is the key to playing the performance role. It can be understood that due to the low dislocation density and thermal stress of the gallium oxide layer in the gallium oxide epitaxial structure in any of the foregoing embodiments, the high-quality gallium oxide layer can not only provide excellent ultraviolet light absorption characteristics, but also has high carrier mobility and good electrical stability. Therefore, the performance and reliability of the ultraviolet detection device can be significantly improved.

[0081] In practical applications, the gallium oxide epitaxial structure in any of the foregoing embodiments can be directly used to prepare an ultraviolet detection device; or it can be used to prepare an ultraviolet detection device after processing the gallium oxide epitaxial structure in any of the foregoing embodiments, such as thinning or removing the substrate in the gallium oxide epitaxial structure.

[0082] Exemplarily, an electrode can be deposited on the gallium oxide layer of the gallium oxide epitaxial structure in any of the foregoing embodiments to obtain an ultraviolet detection device. Among them, the material of the electrode can include, for example, titanium and / or gold.

[0083] The ultraviolet detection device in the embodiment of the present application is prepared by using the gallium oxide epitaxial structure prepared by the epitaxial growth method of the gallium oxide material in any of the foregoing embodiments or the gallium oxide epitaxial structure in any of the foregoing embodiments.

[0084] The technical solution of the present application will be further described below in conjunction with embodiments and comparative examples. Example 1

[0085] The epitaxial growth method of the gallium oxide material in this embodiment includes: Step S101: Using a physical vapor deposition device, magnetron sputtering an AlN material on a sapphire substrate under the conditions of a temperature of 650 °C, a power of 100 W, an argon flow rate of 50 sccm, a nitrogen flow rate of 120 sccm, and an oxygen flow rate of 0.5 sccm to form an aluminum nitride layer with a thickness of 15 nm; Step S102: Place the structure obtained in Step S101 in a box-type annealing furnace and perform high-temperature annealing under a nitrogen atmosphere. The high-temperature annealing temperature is 1680 °C, and the high-temperature annealing time is 60 min. Step S103: Under the conditions of a temperature of 1150 °C, a pressure of 100 mbar, a flow rate of TMAl (the second aluminum source) of 90 sccm, a flow rate of TMGa (gallium source) of 25 sccm, and a flow rate of NH3 (nitrogen source) of 2 slm, epitaxially grow an Al x Ga 1-x N layer (0.2 ≤ x ≤ 0.5) with a thickness of 20 nm on the annealed aluminum nitride layer. During the epitaxial growth process, introduce silane (silicon source) so that the doping concentration of Si in the grown Al x Ga 1-x N layer is 5E17 atoms / cm³. Step S104: First, under the conditions of a temperature of 1000 °C, a pressure of 100 mbar, a flow rate of TMAl (the first aluminum source) of 15 sccm, and a flow rate of oxygen (the first oxygen source) of 50 sccm, epitaxially grow an alumina layer with a thickness of 2 nm on the Al x Ga 1-x N layer. Then, under the conditions of a temperature of 750 °C, a pressure of 100 mbar, a flow rate of TMIn (indium source) of 15 sccm, and a flow rate of oxygen (the second oxygen source) of 50 sccm, epitaxially grow an indium oxide layer with a thickness of 1 nm on the alumina layer. The alumina layer and the indium oxide layer together form a composite interface layer. Step S105: Anneal (heat-treat) the structure obtained in Step S104 under a hydrogen atmosphere. The flow rate of hydrogen is 100 slm, the annealing temperature is 1200 °C, and the annealing time is 20 min. Step S106: Under the conditions of a temperature of 1000 °C, a pressure of 100 mbar, a flow rate of TEGa (the second gallium source) of 300 sccm, and a flow rate of oxygen (the third oxygen source) of 75 sccm, epitaxially grow a gallium oxide layer with a thickness of 1500 nm on the annealed composite interface layer. During the epitaxial growth process, introduce silane (silicon source) so that the doping concentration of Si in the grown gallium oxide layer is 1E18 atoms / cm³.

[0086] Comparative Example 1 The epitaxial growth method of the gallium oxide material in this comparative example includes: Step S201: Magnetron sputtering is carried out using a physical vapor deposition equipment. Under the conditions of a temperature of 650 °C, a power of 100 W, an argon flow rate of 50 sccm, a nitrogen flow rate of 120 sccm, and an oxygen flow rate of 0.5 sccm, an AlN material is sputtered on a sapphire substrate to form an aluminum nitride layer with a thickness of 15 nm; Step S202: The structure obtained in Step S201 is placed in a box-type annealing furnace and subjected to high-temperature annealing in a nitrogen atmosphere. Among them, the temperature of the high-temperature annealing is 1680 °C, and the high-temperature annealing time is 60 min; Step S203: Under the conditions of a temperature of 1150 °C, a pressure of 100 mbar, a flow rate of TMAl of 90 sccm, a flow rate of TMGa of 25 sccm, and a flow rate of NH3 of 2 slm, an Al x Ga 1-x N layer (0.2 ≤ x ≤ 0.5) with a thickness of 20 nm is epitaxially grown on the aluminum nitride layer after high-temperature annealing; During the epitaxial growth process, silane is introduced so that the doping concentration of Si in the grown Al x Ga 1-x N layer is 5E17 atoms / cm³; Step S204: Under the conditions of a temperature of 1000 °C, a pressure of 100 mbar, a flow rate of TEGa of 300 sccm, and an oxygen flow rate of 75 sccm, a gallium oxide layer with a thickness of 1500 nm is epitaxially grown on the Al x Ga 1-x N layer; During the epitaxial growth process, silane is introduced so that the doping concentration of Si in the grown gallium oxide layer is 1E18 atoms / cm³.

[0087] The main difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, a composite interface layer is not epitaxially grown on the Al x Ga 1-x N layer, but a gallium oxide layer is directly epitaxially grown on the Al x Ga 1-x N layer.

[0088] Electrodes are formed on the gallium oxide layers of the gallium oxide epitaxial structures obtained in Example 1 and Comparative Example 1 to obtain a MSM (Metal-Semiconductor-Metal) solar-blind ultraviolet photodetector, and the transmittance, dark current, and response speed of the gallium oxide layer are tested. The test results are shown in Table 1.

[0089] Among them, the transmittance is measured using a UV-VIS ultraviolet-visible spectrophotometer.

[0090] The method for testing the dark current is as follows: Under the irradiation of ultraviolet light at 254 nm, the current and voltage of the MSM solar-blind ultraviolet photodetector are sampled to obtain an I-V (current-voltage) curve. The current with the light source irradiation is called the photocurrent, and the current collected without the light source irradiation is the dark current. The dark current in the present invention corresponds to the current at 5V voltage.

[0091] The response speed can be characterized by the response time, and the response time includes the rise time t r and the fall time t f . Among them, t r is the time taken for the dark current to rise to the highest stable value of the photocurrent from the absence of an optical signal input to the presence of an optical signal input. Specifically, it can be the time required for the current of the device to rise from 10% of the highest value of the photocurrent to 90% of the highest value of the photocurrent; t f is the time taken for the current of the device to drop from the photocurrent to the dark current after the light illumination is removed. Specifically, it can be the time required for the current of the device to drop from 90% of the highest value of the photocurrent to 10% of the highest value of the photocurrent. The smaller t r and t f , the faster the device responds to the change of the optical signal.

[0092] Table 1

[0093] It can be seen from the data in Table 1 that, compared with Comparative Example 1, the transmittance of the gallium oxide layer in the gallium oxide epitaxial structure prepared in Example 1 for ultraviolet light is significantly improved, and the device has a lower dark current and a faster response speed. This shows that in the present application, before epitaxially growing the gallium oxide layer, at least one composite interface layer is epitaxially grown. By utilizing the functions of the composite interface layer to block the diffusion of defects, form low interface states, and reduce phonon scattering, it is beneficial to form better interfacial heat transfer in the gallium oxide epitaxial structure, reduce the generation of thermal stress and the resulting defect proliferation. Therefore, the dislocation density and thermal stress in the gallium oxide layer can be reduced, thereby significantly improving the quality and performance of the gallium oxide layer, and significantly improving the performance and reliability of the device prepared using the gallium oxide epitaxial structure.

[0094] Figure 7 and Figure 8 are the atomic force microscope (AFM) images of the surfaces of the gallium oxide epitaxial structures prepared in Example 1 and Comparative Example 1, respectively.

[0095] From Figure 7 and Figure 8From the comparison, it can be seen that the surface of the gallium oxide epitaxial structure prepared in Example 1 (which can also be considered as the surface of the gallium oxide layer) is significantly flatter than the surface of the gallium oxide epitaxial structure prepared in Comparative Example 1 (which can also be considered as the surface of the gallium oxide layer). The AFM test results also show that the surface roughness of the gallium oxide epitaxial structure prepared in Example 1 is 0.61 nm, and the surface roughness of the gallium oxide epitaxial structure prepared in Comparative Example 1 is 3.46 nm. This further indicates that in the present application, due to the function of the composite interface layer in blocking the diffusion of defects, forming low interface states, and reducing phonon scattering, it can effectively block the diffusion of dislocations and other defects to the upper epitaxial layer, improve the thermal management of the device, so that the dislocation density and thermal stress in the gallium oxide layer are both low. Therefore, the gallium oxide layer has a relatively flat surface and high quality. In Comparative Example 1, since the composite interface layer is not formed, dislocations and other defects are likely to diffuse to the upper epitaxial layer, the interfacial heat transfer cannot be improved, and thermal stress is easily generated. The thermal stress will further lead to the rapid proliferation of defects, resulting in both high dislocation density and thermal stress in the gallium oxide layer, and then leading to an obviously uneven surface morphology of the gallium oxide layer, and the quality of the gallium oxide layer is poor, which will further affect the performance and reliability of the corresponding device.

[0096] It should be noted that the gallium oxide epitaxial structure embodiments, the epitaxial growth method embodiments of gallium oxide materials, and the ultraviolet detection device embodiments provided in the present application belong to the same concept; among the technical features in the technical solutions recorded in each embodiment, without conflict, they can be combined arbitrarily. However, it should be further noted that for the gallium oxide epitaxial structure provided in the embodiments of the present application, the combination of its various technical features can already solve the technical problems to be solved in the present application; therefore, the gallium oxide epitaxial structure provided in the embodiments of the present application can be independent of the epitaxial growth method of the gallium oxide materials provided in the embodiments of the present application, and the epitaxial structure grown by any epitaxial growth method that can form the gallium oxide epitaxial structure provided in the embodiments of the present application is within the protection scope of the present application.

[0097] It should be understood that the above embodiments are all exemplary and do not cover all possible implementation manners. Without departing from the scope of the present disclosure, various deformations and changes can be made based on the above embodiments. Similarly, the various technical features of the above embodiments can also be combined arbitrarily to form other embodiments of the present application that may not be clearly described. Therefore, the above embodiments only represent several implementation manners of the present application and do not limit the protection scope of the patent of the present application.

Claims

1. A method for epitaxial growth of gallium oxide material, characterized in that: The method comprises: providing a substrate; forming an aluminum nitride layer on the substrate; epitaxially growing at least one composite interface layer on the aluminum nitride layer, wherein the composite interface layer comprises an aluminum oxide layer and an indium oxide layer stacked in sequence; A gallium oxide layer is epitaxially grown on the composite interface layer.

2. The epitaxial growth method of gallium oxide material according to claim 1, characterized in that: Epitaxially growing the composite interface layer comprises: A first aluminum source and a first oxygen source are introduced to epitaxially grow the aluminum oxide layer; the epitaxial growth of the aluminum oxide layer satisfies at least one of the following conditions: (1) The temperature of epitaxial growth is 600℃~800℃; (2) The pressure of epitaxial growth is 20mbar~150mbar; (3) The flow rate of the first aluminum source is greater than or equal to 5 sccm and less than or equal to 20 sccm; (4) The flow rate of the first oxygen source is greater than 0 sccm and less than or equal to 100 sccm; (5) The time of epitaxial growth is 1s~5s.

3. The epitaxial growth method of gallium oxide material according to claim 2, characterized in that: Epitaxially growing the composite interface layer further comprises: An indium source and a second oxygen source are introduced to epitaxially grow the indium oxide layer on the aluminum oxide layer; the epitaxial growth of the indium oxide layer satisfies at least one of the following conditions: (1) The temperature of epitaxial growth is 600℃~800℃; (2) The pressure of epitaxial growth is 20mbar~150mbar; (3) The flow rate of the indium source is greater than or equal to 5 sccm and less than or equal to 20 sccm; (4) The flow rate of the second oxygen source is greater than 0 sccm and less than or equal to 100 sccm; (5) The time of epitaxial growth is 1s~10s.

4. The epitaxial growth method of gallium oxide material according to claim 1, characterized in that: Before epitaxially growing at least one layer of the composite interface layer on the aluminum nitride layer, the method further comprises: A second aluminum source, a gallium source and a nitrogen source are introduced to epitaxially grow Al on the aluminum nitride layer. x Ga 1-x N layer, wherein 0.2≤x≤0.5; epitaxially growing the Al x Ga 1-x N layers, satisfying at least one of the following conditions: (1) The temperature of epitaxial growth is 1000℃~1200℃; (2) The pressure of epitaxial growth is 50mbar~100mbar; (3) The flow rate of the second aluminum source is greater than or equal to 50 sccm and less than or equal to 300 sccm; (4) The flow rate of the gallium source is greater than or equal to 20 sccm and less than or equal to 100 sccm; (5) The flow rate of the nitrogen source is greater than or equal to 0.5 slm and less than or equal to 2 slm; (6) Al x Ga 1-x The thickness of the N layer is 5nm~30nm.

5. The epitaxial growth method of gallium oxide material according to claim 1, characterized in that: Before epitaxially growing the gallium oxide layer on the composite interface layer, the method further comprises: The composite interface layer is subjected to heat treatment; the heat treatment satisfies at least one of the following conditions: (1) The temperature of the heat treatment is 1000°C to 1400°C; (2) The heat treatment time is 10 min to 30 min; (3) The heat treatment is performed in an atmosphere including hydrogen.

6. The epitaxial growth method of gallium oxide material according to any one of claims 1 to 5, characterized in that: The method satisfies at least one of the following conditions: (1) The thickness of the composite interface layer is 1 nm to 5 nm; (2) The thickness of the aluminum oxide layer is 0.5 nm to 3 nm; (3) The thickness of the indium oxide layer is 0.5 nm to 2 nm; (4) The thickness of the aluminum nitride layer is 5 nm to 50 nm; (5) The thickness of the gallium oxide layer is 500nm~2500nm; (6) The number of the composite interface layers is greater than or equal to 2, and the composite interface layers are identical.

7. A gallium oxide epitaxial structure, characterized in that: include: substrate; an aluminum nitride layer on the substrate; At least one composite interface layer located on the aluminum nitride layer, the composite interface layer comprising an aluminum oxide layer and an indium oxide layer stacked in sequence; A gallium oxide layer is located on the composite interface layer.

8. The gallium oxide epitaxial structure according to claim 7, characterized in that: The gallium oxide epitaxial structure satisfies at least one of the following conditions: (1) The thickness of the composite interface layer is 1 nm to 5 nm; (2) The thickness of the aluminum oxide layer is 0.5 nm to 3 nm; (3) The thickness of the indium oxide layer is 0.5 nm to 2 nm; (4) The thickness of the aluminum nitride layer is 5 nm to 50 nm; (5) The thickness of the gallium oxide layer is 500nm~2500nm; (6) The number of the composite interface layers is greater than or equal to 2, and the composite interface layers are identical.

9. The gallium oxide epitaxial structure according to claim 7 or 8, characterized in that: The gallium oxide epitaxial structure further includes: an Al2O3 layer located between the aluminum nitride layer and the composite interface layer. x Ga 1-x N layers, where 0.2≤x≤0.

5.

10. An ultraviolet detection device, characterized in that: A gallium oxide epitaxial structure obtained by the epitaxial growth method of the gallium oxide material according to any one of claims 1 to 6 or a gallium oxide epitaxial structure according to any one of claims 7 to 9.

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