Gallium nitride power device epitaxial layer structure and preparation method

Abstract

The embodiment of the present invention discloses an epitaxial layer structure of a gallium nitride power device, comprising a substrate, a high resistance structure layer, a high resistance GaN layer, a channel layer and a barrier layer stacked in sequence from bottom to top; the high resistance structure layer comprises a Si-containing material layer and an Al-containing material layer, and the Al-containing material layer is located between the high resistance GaN and the Si-containing material layer; the constituent elements of the Al-containing material layer include Al and N. In the embodiment of the present invention, the epitaxial layer structure of the gallium nitride power device improves the resistance of the gallium nitride layer and the withstand voltage characteristics of the gallium nitride device by matching the Si-containing material layer and the Al-containing material layer, while avoiding the side effects caused by additional doping.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials and devices, and in particular to a gallium nitride power device epitaxial layer structure and a method for preparing the gallium nitride power device epitaxial layer structure. Background Art

[0002] Gallium nitride (GaN) materials offer significantly superior performance to first- and second-generation semiconductor materials such as silicon (Si), germanium (Ge), and gallium arsenide (GaAs) in high-power, high-temperature, high-frequency, and radiation-resistant microelectronics, as well as in short-wavelength optoelectronics. This is particularly evident in the heterojunction structure of GaN materials (typically AlGaN / GaN). Due to the strong spontaneous polarization and piezoelectric polarization effects of the epitaxially grown structure along the Ga plane, a high concentration of two-dimensional electron gas (2DEG) is generated at the AlGaN / GaN heterojunction interface, resulting in lower on-resistance in GaN devices. Furthermore, at the same withstand voltage level, GaN materials are more suitable for the fabrication of high-efficiency power electronic devices, particularly lateral high electron mobility transistors (HEMTs). Their on-resistance is 1 to 2 orders of magnitude lower than that of Si devices and 1 / 2 to 1 / 3 lower than that of SiC devices, also a third-generation semiconductor material.

[0003] In addition to the low on-resistance of 2DEG, a high-resistance GaN layer is also key to high-voltage devices. Currently, how to prepare a high-resistance GaN layer remains a concern within the industry. Summary of the Invention

[0004] To address at least some of the problems and shortcomings in the prior art, embodiments of the present invention disclose a gallium nitride power device epitaxial layer structure and a method for preparing a gallium nitride power device epitaxial layer structure, which effectively improve the resistance of the gallium nitride layer and the withstand voltage characteristics of the gallium nitride device.

[0005] In one aspect, an embodiment of the present invention provides a gallium nitride power device epitaxial layer structure, comprising:

[0006] The substrate, high-resistance structural layer, high-resistance GaN layer, channel layer, and barrier layer are stacked sequentially from bottom to top. The high-resistance structural layer includes a Si-containing material layer and an Al-containing material layer, with the Al-containing material layer located between the high-resistance GaN and Si-containing material layers. The Al-containing material layer is composed of elements including Al and N.

[0007] On the other hand, an embodiment of the present invention provides a method for preparing an epitaxial layer structure of a gallium nitride power device, comprising:

[0008] S1: growing a high resistance structural layer on the substrate;

[0009] S2: growing a high-resistance GaN layer on the high-resistance structural layer;

[0010] S3: growing a channel layer on the high-resistance GaN layer;

[0011] S4: growing a barrier layer on the channel layer to obtain the epitaxial layer structure of the gallium nitride power device;

[0012] The high-resistance structural layer in the epitaxial layer structure of the gallium nitride power device includes a Si-containing material layer and an Al-containing material layer, and the Al-containing material layer is located between the high-resistance GaN and the Si-containing material layer. The constituent elements of the Al-containing material layer include Al and N.

[0013] As can be seen from the foregoing, the technical solutions of the above-described embodiments of the present invention can achieve one or more of the following beneficial effects: A high-resistance GaN epitaxial layer is achieved by combining a Si-containing material layer with an Al-containing material layer, effectively improving the resistance of the GaN layer and the withstand voltage characteristics of the GaN device, thus meeting the high withstand voltage requirements of GaN power devices. Furthermore, a high-resistance GaN epitaxial layer can be achieved without the need for additional Fe and C doping sources. Furthermore, the absence of Fe in the epitaxial layer and the low C content mitigate the device's dynamic performance instability caused by the Fe source memory effect and C doping stability. Furthermore, the defect density of the GaN layer is reduced, thereby optimizing device performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 A schematic structural diagram of an epitaxial layer structure of a gallium nitride power device provided by an embodiment of the present invention;

[0016] Figure 2 for Figure 1 A schematic structural diagram of another embodiment of the epitaxial layer structure of a gallium nitride power device;

[0017] Figure 3 for Figure 1 A schematic structural diagram of another embodiment of the epitaxial layer structure of a gallium nitride power device;

[0018] Figure 4 A schematic flow chart of a method for preparing an epitaxial layer structure of a gallium nitride power device provided in an embodiment of the present invention;

[0019] Figure 5 for Figure 1Secondary ion mass spectrometry elemental analysis diagram of the epitaxial layer structure of the gallium nitride power device;

[0020] Figure 6 for Figure 1 Resistance experimental comparison and analysis chart of medium and high resistance GaN layers;

[0021] Figure 7 for Figure 1 Experimental comparison and analysis of GaN power devices made of a medium-epitaxial layer structure and a GaN power device made of a high-resistance GaN layer doped with C.

[0022] [Explanation of main reference numerals]

[0023] 1: substrate; 2: high-resistance structural layer; 21: Si-containing material layer; 210: first Si layer; 211: second Si layer; 22: Al-containing material layer; 220: first Al material layer; 221: second Al material layer; 3: high-resistance GaN layer; 4: channel layer; 5: barrier layer. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] It should also be noted that the division of multiple embodiments in the present invention is only for the convenience of description and should not constitute a special limitation. The features in various embodiments can be combined and referenced to each other without contradiction.

[0027] Reference Figure 1As shown, an embodiment of the present invention provides a gallium nitride power device epitaxial layer structure, comprising: a substrate 1, a high-resistance structural layer 2, a high-resistance GaN layer 3, a channel layer 4, and a barrier layer 5 stacked in order from bottom to top. The high-resistance structural layer 2 includes a Si-containing material layer 21 and an Al-containing material layer 22, with the Al-containing material layer 22 located between the high-resistance GaN and Si-containing material layers 21. The constituent elements of the Al-containing material layer 22 include Al and N.

[0028] The epitaxial layer structure of the gallium nitride power device is a multi-layer structure formed by sequentially depositing the substrate 1 material through epitaxial growth technology during the manufacturing process of the gallium nitride (GaN) power device to improve the voltage resistance. The substrate 1 is located at the bottom of the epitaxial layer structure and is the basic support part of the entire epitaxial layer structure. The substrate 1 can be, for example, a sapphire substrate, which has good corrosion resistance and relatively low cost. The high-resistance structural layer 2 is a superposition of a Si-containing material layer 21 and an Al-containing material layer 22, wherein the Si material in the Si-containing material layer 21 can be, for example, a Si single layer or a Si-containing Al material layer with the first Al material layer 220 as the matrix, and the Al material in the Al-containing material layer 22 can be, for example, AlN or AlGaN.

[0029] The high-resistance GaN layer 3 is a gallium nitride (GaN) layer with a relatively high resistivity, which can effectively limit the movement of carriers (such as electrons). In power devices, the unrestrained movement of carriers may cause problems such as leakage, affecting the performance of the device. The channel layer 4 is the main channel for the transmission of carriers (such as electrons), and the properties of the channel layer 4 directly determine the current conduction capability of the device. In some embodiments, the barrier layer 5 is an aluminum gallium nitride (AlGaN) layer, and the channel layer 4 is a gallium nitride (GaN) layer. The Al component in the barrier layer 5 is between 20% and 30%. The barrier layer 5 and the channel layer 4 form an AlGaN / GaN heterostructure. Due to the band offset between the AlGaN layer and the GaN layer, a two-dimensional electron gas (2DEG) is formed at the interface. 2DEG is a high-mobility carrier channel.

[0030] In addition, the epitaxial layer structure of the GaN power device also includes an isolation layer and a cap layer. The isolation layer is used to increase the electron density of the two-dimensional electron gas, reduce resistance, and increase mobility. For example, in some embodiments, the isolation layer is made of AlN and is located between the barrier layer 5 and the channel layer 4. The cap layer is a thin layer located at the outermost layer of the device, covering other functional layers, mainly to protect the internal functional layers. The cap layer can be made of GaN or SiNx, for example.

[0031] Reference Figure 6As shown, control group 1 has no Si-containing material layer 21 and no Al-containing material layer 22 in the epitaxial layer structure of the gallium nitride power device. Control group 2 has no Si-containing material layer 21 and an Al-containing material layer 22 in the epitaxial layer structure of the gallium nitride power device. Control group 3 has a high-resistance GaN layer 3 doped with C in the epitaxial layer structure of the gallium nitride power device. The experimental group has a Si-containing material layer 21 and an Al-containing material layer 22 in the epitaxial layer structure of the gallium nitride power device. The vertical axis is the resistance (Ω) using a logarithmic scale; the horizontal axis represents different experimental conditions. According to the experimental data, the resistance of the GaN layer grown in control group 1 is 2.8×10 3 Ω, the resistance of the GaN layer grown in control group 2 is 8.7×10 3 Ω, the resistance of the GaN layer grown in control group 3 is 6.1×10 12 Ω, the resistance of the GaN layer grown in the experimental group is 1.0×1013Ω. In the absence of the Si-containing material layer 21 and the Al-containing material layer 22 (control group 1), the resistance is relatively low. When the Al-containing material layer 22 is added (control group 2), the resistance increases significantly. When the Si-containing material layer 21 and the Al-containing material layer 22 are added at the same time (experimental group), the resistance increases sharply, reaching 1.0×1013Ω, which is slightly higher than the resistance of the high-resistance GaN layer 3 doped with C (control group 3). Figure 7 As shown, device specifications are Ig < 60nA and Id < 200nA. GaN power devices fabricated with a high-resistance GaN layer 3 doped with C (control group 3) and a GaN power device fabricated with a Si-containing material layer 21 and an Al-containing material layer 22 (experimental group) exhibit comparable Ig and Id leakage levels. The experimental group lacks C doping to prevent C from affecting device dynamic stability. Ultimately, verification demonstrates that a high-resistance GaN layer 3 can be grown in the epitaxial structure of a GaN power device by stacking a Si-containing material layer 21 and an Al-containing material layer 22.

[0032] In some embodiments of the present invention, reference Figure 2 As shown, the Si-containing material layer 21 includes a first Si layer 210 and a second Si layer 211. The Al-containing material layer 22 includes a first Al material layer 220 and a second Al material layer 221. In the high-resistance structure, the first Si layer 210, the first Al material layer 220, the second Si layer 211, and the second Al material layer 221 are sequentially disposed on the substrate 1.

[0033] Reference Figure 2As shown, the epitaxial layer structure of the GaN power device includes: a substrate 1, a first Si layer 210, a first Al material layer 220, a second Si layer 211, a second Al material layer 221, a high-resistance GaN layer 3, a channel layer 4, and a barrier layer 5 stacked in sequence from bottom to top. There may be no obvious interface between the Si-containing material layer 21 and the Al-containing material layer 22, and the Si signal can be measured by secondary ion mass spectrometry (SIMS) elemental analysis. Figure 5 As shown, the horizontal axis represents the depth (Depth, in nm), and the vertical axis represents the concentration (Concentration, in atoms / cm 3 ). Shows the concentration (concentration, unit: atoms / cm) of different elements (C-carbon, O-oxygen, Si-silicon and Al-aluminum) at different depths (Depth, unit: nm). 3 ) changes.

[0034] As can be seen from the figure, the concentration of carbon (C) is relatively low and stable across the entire depth range, while the concentration of oxygen (O) exhibits significant fluctuations at different depths. The concentration of silicon (Si) has a significant peak at a specific depth, and the concentration of aluminum (Al) exhibits significant peaks and variations at different depths. Ultimately, SIMS analysis revealed that within the entire GaN power device epitaxial layer structure, silicon (Si) content was detected on the surface of substrate 1 and in the Al-containing material layer 22. Furthermore, as can be seen from the figure, the oxygen (O) content differs between the first Al material layer 220 and the second Al material layer 221, while the overall carbon (C) concentration is relatively low. Therefore, a distinct Al-containing material layer 22 can be detected.

[0035] In some embodiments of the present invention, reference Figure 2 As shown, the first Si layer 210 is an Al material layer or a Si single layer containing Si based on the first Al material layer 220 on the substrate 1. The second Si layer 211 is an Al material layer or a Si single layer containing Si based on the first Al material layer 220. Si usually acts as a donor impurity in semiconductor materials and provides additional electrons to the crystal structure. In a high electric field environment, the electrons provided by Si are easily driven by the electric field, forming an unwanted leakage current, resulting in leakage, thereby reducing the performance of the device. Secondly, in the subsequent epitaxial layer growth process, Si atoms have a certain diffusion tendency. In this embodiment, by providing a second Al material layer 221 on the side of the second Si layer 211 away from the substrate 1 and combining it with a high-resistance GaN layer 3, Si atoms can be prevented from moving from their original position to other functional layers (such as the channel layer 4). This prevents the diffusion of Si atoms from damaging the originally designed electrical structure of the device and the occurrence of leakage problems.

[0036] In some embodiments of the present invention, reference Figure 3 As shown, in the high-resistance structure, a Si-containing material layer 21 is disposed on a substrate 1, and an Al-containing material layer 22 is disposed on the Si-containing material layer 21. The epitaxial layer structure of a GaN power device comprises, stacked from bottom to top, a substrate 1, a Si-containing material layer 21, an Al-containing material layer 22, a high-resistance GaN layer 3, a channel layer 4, and a barrier layer 5. The high-resistance structure can be constructed by stacking multiple sets of Al-containing material layers 22 and Si-containing material layers 21, or by stacking only one set of Al-containing material layers 22 and Si-containing material layers 21. The GaN power device epitaxial layer structure only requires the stacking of the Al-containing material layer 22 and the Si-containing material layer 21; these stackings can significantly improve the resistance of the original high-resistance GaN layer 3.

[0037] Reference Figure 5 As shown, the high resistance GaN layer 3 grown in this embodiment is not doped with additional Fe source and C source. Figure 5 The SIMS concentration test showed that no Fe element was detected and the C element content was at a low concentration (the C content was less than 1×10 17 cm -3 As a non-doped layer, there is no additional impurity doping (such as Fe source and C source, etc.), which avoids other side effects such as increased leakage channels caused by the introduction of excessive carriers due to doping. Moreover, according to the experimental results, it can be seen that the resistance of the high-resistance GaN layer 3 grown without doping is equivalent to that of the high-resistance GaN layer 3 obtained by additional doping with Fe source and C source. The high-resistance GaN layer 3 in this embodiment avoids the memory effect caused by the additional doping with Fe source, which reduces the mobility of carriers, and avoids the additional doping with C source, which makes the C content too high (for example, the C content of self-doping or additional doping with C source is greater than 1×10 18 cm -3 ) to prevent excessive carbon source pollution of the reactor environment or the problem of unstable device dynamic performance caused by C doping stability factors.

[0038] In some embodiments of the present invention, the Si-containing material layer 21 is a single layer or a Si-containing Al material layer based on the first Al material layer 220. The Si-containing material layer 21 is interposed between the substrate 1 and the Al-containing material layer 22, primarily to reduce defects in the Al-containing material layer 22 and improve the crystal quality of the Al-containing material layer 22.

[0039] In some embodiments of the present invention, the Al-containing material layer 22 is an aluminum nitride layer or an aluminum gallium nitride layer. The aluminum nitride (AlN) layer and the aluminum gallium nitride (AlGaN) layer serve as the connecting layer between the high-resistance GaN layer 3 and the substrate 1. The Si-containing material layer 21 is used to improve the crystal quality of the connecting layer of the Al-containing material layer 22, further reducing the defects of the high-resistance GaN layer 3 and obtaining a higher resistance effect. In the AlGaN / GaN heterostructure, due to the band offset between the AlGaN layer and the GaN layer, a two-dimensional electron gas (2DEG) is formed at the interface. However, not all current flows in the channel layer 4, causing current leakage. This problem can be solved by increasing the resistance of the high-resistance GaN layer 3. From the experimental results, it can be found that the resistance of the high-resistance GaN layer 3 will be greatly increased through the high-resistance structure, effectively reducing the current leakage problem, thereby optimizing the electrical performance of the device.

[0040] In addition, refer to Figure 4 As shown, an embodiment of the present invention provides a method for preparing an epitaxial layer structure of a gallium nitride power device, comprising:

[0041] S1: growing a high resistance structural layer on the substrate;

[0042] S2: growing a high-resistance GaN layer on the high-resistance structural layer;

[0043] S3: growing a channel layer on the high-resistance GaN layer;

[0044] S4: growing a barrier layer on the channel layer to obtain the epitaxial layer structure of the gallium nitride power device;

[0045] The high-resistance structural layer in the epitaxial layer structure of the gallium nitride power device includes a Si-containing material layer and an Al-containing material layer, and the Al-containing material layer is located between the high-resistance GaN and the Si-containing material layer. The constituent elements of the Al-containing material layer include Al and N.

[0046] Specifically, for example, in step S1, a flat Al2O3 (sapphire) substrate can be selected as the substrate. In step S2, a high-resistance GaN layer is grown on the Al-containing material layer of the high-resistance structural layer at a temperature between 1000 and 1150°C and a thickness range of 1 to 4 μm. The high-resistance GaN layer in step S2 can be obtained through conditions such as the epitaxial GaN V / III ratio temperature field, and the high-resistance GaN layer can be a non-doped high-resistance GaN layer. Secondly, in step S3, for example, a 100nm to 300nm GaN layer can be grown on the high-resistance GaN layer as a channel layer, and in step S4, for example, a 15nm to 30nm thick AlGaN layer can be grown on the channel layer as a barrier layer, and the Al component in the barrier layer is 20% to 30%. In addition, a 1nm-2nm AlN layer can be grown on the channel layer as an isolation layer, and a 1nm-4nm thick GaN or SiNx layer can be grown on the barrier layer as a cap layer on the surface of the epitaxial layer.

[0047] In some embodiments of the present invention, the Si-containing material layer includes a first Si layer and a second Si layer. The Al-containing material layer includes a first Al material layer and a second Al material layer. The specific steps of S1 are:

[0048] S11: introducing Si for the first time and preparing a first Al material layer on the substrate to obtain a first Si layer and a first Al material layer sequentially arranged on the substrate.

[0049] S12: Si is introduced for the second time, and a second Al material layer is prepared on the first Al material layer, so as to obtain a second Si layer and a second Al material layer sequentially arranged on the first Al material layer.

[0050] Specifically, in step S11, Si gas is introduced into the substrate to form a Si atmosphere to obtain a first Si layer, and a first Al material layer with a thickness of 20 to 40 nm is deposited on the first Si layer. In step S12, Si gas is introduced again to form a second Si layer on the first Al material layer, and then a second Al material layer with a thickness of 40 nm is grown.

[0051] In some embodiments of the present invention, the specific step S1 is: introducing Si and preparing an Al-containing material layer on the substrate to obtain a Si-containing material layer and an Al-containing material layer sequentially arranged on the substrate.

[0052] Specifically, Si gas is introduced onto the substrate to form a Si-containing material layer, and then a 40 nm Al-containing material layer is grown.

[0053] The method for preparing the epitaxial layer structure of a gallium nitride power device provided in this embodiment relies on the combination of a Si-containing material layer and an Al-containing material layer to grow a low-defect, high-quality Al material, thereby significantly improving the resistance of the high-resistance GaN layer. No additional Fe and C sources are required during the preparation process, thus avoiding the reduction in carrier mobility caused by additional doping and preventing the complication of electrical performance.

[0054] It can be understood that the aforementioned embodiments are merely exemplary descriptions of the present invention. The technical solutions of the various embodiments can be arbitrarily combined and used in conjunction with each other, provided that the technical features do not conflict, the structures do not contradict, and the purpose of the present invention is not violated.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A gallium nitride power device epitaxial layer structure, characterized in that: It includes a substrate, a high-resistance structure layer, a high-resistance GaN layer, a channel layer and a barrier layer stacked in sequence from bottom to top; the high-resistance structure layer includes a Si-containing material layer and an Al-containing material layer, and the Al-containing material layer is located between the high-resistance GaN and the Si-containing material layer; the constituent elements of the Al-containing material layer include Al and N.

2. The gallium nitride power device epitaxial layer structure according to claim 1, characterized in that: The Si-containing material layer includes a first Si layer and a second Si layer; the Al-containing material layer includes a first Al material layer and a second Al material layer; in the high-resistance structure, the first Si layer, the first Al material layer, the second Si layer and the second Al material layer are sequentially arranged on the substrate.

3. The gallium nitride power device epitaxial layer structure according to claim 1, characterized in that: In the high resistance structure, the Si-containing material layer is arranged on the substrate, and the Al-containing material layer is arranged on the Si-containing material layer.

4. The epitaxial layer structure of a gallium nitride power device according to claim 2, characterized in that: The first Si layer is an Al material layer or a Si single layer containing Si based on the first Al material layer on the substrate; the second Si layer is an Al material layer or a Si single layer containing Si based on the first Al material layer.

5. The gallium nitride power device epitaxial layer structure according to claim 1, characterized in that: The barrier layer is an aluminum gallium nitride layer, and the channel layer is a gallium nitride layer.

6. The gallium nitride power device epitaxial layer structure according to claim 1, characterized in that: The Si-containing material layer is a Si single layer or a Si-containing Al material layer based on the first Al material layer.

7. The gallium nitride power device epitaxial layer structure according to claim 1, characterized in that: The Al-containing material layer is an aluminum nitride layer or an aluminum gallium nitride layer.

8. A method for preparing an epitaxial layer structure of a gallium nitride power device, characterized in that: The following steps are involved: S1: growing a high resistance structure layer on the substrate; S2: growing a high-resistance GaN layer on the high-resistance structural layer; S3: growing a channel layer on the high resistance GaN layer; S4: growing a barrier layer on the channel layer to obtain the epitaxial layer structure of the gallium nitride power device; The high resistance structure layer in the epitaxial layer structure of the gallium nitride power device includes a Si-containing material layer and an Al-containing material layer, and the Al-containing material layer is located between the high resistance GaN and the Si-containing material layer, and constituent elements of the Al-containing material layer include Al and N.

9. The method for preparing the epitaxial layer structure of a gallium nitride power device according to claim 8, characterized in that: The Si-containing material layer includes a first Si layer and a second Si layer; the Al-containing material layer includes a first Al material layer and a second Al material layer; the specific steps of S1 are: S11: introducing Si for the first time and preparing the first Al material layer on the substrate to obtain the first Si layer and the first Al material layer sequentially disposed on the substrate; S12: introducing Si for the second time and preparing the second Al material layer on the first Al material layer to obtain the second Si layer and the second Al material layer sequentially disposed on the first Al material layer.

10. The method for preparing the epitaxial layer structure of a gallium nitride power device according to claim 9, characterized in that: The specific steps of S1 are: Si is introduced and the Al-containing material layer is prepared on the substrate to obtain the Si-containing material layer and the Al-containing material layer sequentially arranged on the substrate.

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