Epitaxial layer of gallium nitride HEMT device on substrate and manufacturing method

Abstract

The invention discloses an epitaxial layer of a gallium nitride HEMT (High Electron Mobility Transistor) device on a substrate and a manufacturing method, and the epitaxial layer comprises the substrate, and a SiO2 discontinuous layer, an AlN nucleating layer, an AlGaN layer, a buffer layer, a high-carbon GaN layer, a low-carbon GaN channel layer, an AlGaN barrier layer and a cap layer which are sequentially stacked on the surface of the substrate along the longitudinal direction, random irregular similar triangles are distributed on the surface of the SiO2 discontinuous layer, so that part of the substrate can be exposed out of the surface of the SiO2 discontinuous layer. According to the epitaxial structure, the substrate is discontinuously covered by the random irregular SiO2 thin layer which is similar to a triangle, the HEMT structure is grown on the substrate, so that the density of GaN penetrating dislocation in the high-carbon GaN layer and the low-carbon GaN channel layer is reduced, and the performance and the reliability of an HEMT power device prepared by using the epitaxial structure with the low dislocation density are improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors, and specifically to an epitaxial layer of a gallium nitride HEMT device on a substrate and a manufacturing method thereof. Background Art

[0002] The common epitaxial layer structures in the prior art are as Figure 1 shown. From bottom to top, they successively include a substrate (such as a silicon substrate), an aluminum nitride (AlN) nucleation layer, an AlGaN layer, where the AlGaN layer is composed of one or more AlGaN layers with different aluminum contents, a buffer layer (Buffer layer), where the buffer layer is composed of a superlattice buffer layer formed by alternately and periodically forming AlN and AlGaN. Above the buffer layer are successively a high-carbon GaN layer, a low-carbon GaN channel layer, an AlGaN barrier layer, and a capping layer. In the above structure, due to the large lattice mismatch between GaN / AlN and silicon in the substrate, a high density of dislocations will be generated during the epitaxial growth process, and these dislocations will penetrate through the epitaxial growth to the surface of the epitaxial layer all the time, resulting in a high density of penetrating dislocations in the low-carbon GaN channel layer, which is crucial for the performance of the gallium nitride high electron mobility transistor device, as well as in the subsequent AlGaN barrier layer and capping layer. These dislocations will reduce the device performance and reliability.

[0003] The optimized epitaxial layer structure in the prior art is as Figure 2 shown. The difference from the first one is that a GaN layer is grown first above the buffer layer, and then a periodic and regular silicon dioxide SiO2 mask is formed on this layer through technologies such as deposition - lithography - etching. Subsequently, a low-carbon GaN channel layer and subsequent AlGaN barrier layer and capping layer are grown on the patterned epitaxial structure. In the above optimized epitaxial structure, before growing the low-carbon GaN channel layer, a periodic SiO2 mask is formed on the GaN layer to block the continuous upward extension of the penetrating dislocations, so that the dislocation density of the subsequent low-carbon GaN channel layer and the above layers can be greatly reduced. However, the second epitaxial structure has the following two major disadvantages: 1. Additional deposition - lithography - etching steps are required to form a periodic SiO2 mask, which increases the cost; 2. Introducing the SiO2 mask brings about an interruption in the epitaxial growth, resulting in interface problems. At the same time, the difficulty of secondary epitaxial growth of GaN on the SiO2 mask is relatively high, and there will be a series of problems such as the epitaxial layer not being able to merge smoothly and the appearance of holes in the epitaxy. Summary of the Invention

[0004] In order to overcome the defects in the prior art, the embodiments of the present invention provide an epitaxial layer of a gallium nitride HEMT device on a substrate and a manufacturing method thereof, which are used to solve one or more of the above problems.

[0005] Embodiments of the present application disclose: An epitaxial layer of a gallium nitride HEMT device on a substrate, comprising a substrate, and a SiO2 discontinuous layer, an AlN nucleation layer, an AlGaN layer, a buffer layer, a high-carbon GaN layer, a low-carbon GaN channel layer, an AlGaN barrier layer, and a cap layer that are sequentially stacked along the longitudinal direction on the surface of the substrate. Among them, randomly irregular triangle-like shapes are distributed on the surface of the SiO2 discontinuous layer, which can expose part of the substrate on its surface.

[0006] Further, the substrate is a silicon substrate or a single-crystalline silicon thin film on an insulator.

[0007] Further, the buffer layer is a superlattice buffer layer formed by alternately and periodically arranging AlN and AlGaN.

[0008] Further, the thickness of the buffer layer is 0.3 μm - 15 μm, the thickness of the AlN nucleation layer is 30 nm - 1500 nm, and the thickness of the AlGaN layer is 25 nm - 400 nm.

[0009] Embodiments of the present application also disclose a manufacturing method of a gallium nitride HEMT device on a substrate, comprising the following steps: preparing a substrate; forming a SiO2 continuous layer on the surface of the substrate; removing part of the SiO2 continuous layer to form a SiO2 discontinuous layer; epitaxially growing an AlN nucleation layer on the SiO2 discontinuous layer; and epitaxially growing and forming an AlGaN layer, a buffer layer, a high-carbon GaN layer, a low-carbon GaN channel layer, an AlGaN barrier layer, and a cap layer in sequence along the longitudinal direction on the surface of the AlN nucleation layer.

[0010] Further, in the epitaxial growth process, metal organic chemical vapor deposition or molecular beam epitaxy method is adopted.

[0011] Further, in the step of "preparing a substrate", the thickness of the substrate is 300 μm - 3000 μm, and the resistivity is 0.001 Ω·cm - 5000 Ω·cm.

[0012] Further, in the step of "forming a SiO2 continuous layer on the surface of the substrate", the SiO2 continuous layer completely covers the surface of the substrate, and the thickness of the SiO2 continuous layer is 0.5 nm - 5 nm.

[0013] Further, in the step of "removing part of the SiO2 continuous layer to form a SiO2 discontinuous layer", the following steps are included: processing the SiO2 continuous layer in a metal organic chemical vapor deposition (MOCVD) furnace, or etching part of the SiO2 continuous layer with hydrofluoric acid, so that part of the SiO2 continuous layer on the surface is removed and the substrate below it is exposed, and randomly irregular triangle-like shapes are distributed on the surface of the remaining SiO2 discontinuous layer.

[0014] Further, in the step of "epitaxially growing an AlN nucleation layer on the discontinuous SiO2 layer", the following steps are included: AlN first starts to deposit only on the surface where the substrate is exposed to form a plurality of mutually spaced AlN islands; AlN continues to grow epitaxially so that the AlN islands gradually merge to form a continuous AlN nucleation layer, and the thickness of the AlN nucleation layer is 30 nm - 1500 nm.

[0015] The beneficial effects of the present invention are as follows:

[0016] The substrate is discontinuously covered by randomly irregular thin SiO2 layers, and only part of the substrate is exposed on the surface. Growing a HEMT structure on such a substrate reduces the density of GaN threading dislocations in the high-carbon GaN layer and the low-carbon GaN channel layer. The performance and reliability of HEMT power devices prepared using such an epitaxial structure with a low dislocation density are improved. In addition, by directly forming a discontinuous SiO2 layer on the substrate, no additional deposition-lithography-etching steps are required, effectively reducing costs. At the same time, the thickness of the discontinuous SiO2 layer can be made very thin, with little impact on the subsequent epitaxial AlN nucleation layer and the entire HEMT structure, a large epitaxial window, and a high epitaxial production yield.

[0017] To make the above and other objects, features, and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given below in conjunction with the accompanying drawings and are described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 is a schematic structural diagram of an epitaxial layer of a gallium nitride HEMT device on a substrate in an embodiment of the prior art;

[0020] Figure 2 is a schematic structural diagram of an epitaxial layer of a gallium nitride HEMT device on a substrate in another embodiment of the prior art;

[0021] Figure 3 is a schematic structural diagram of an epitaxial layer of a gallium nitride HEMT device on a substrate in an embodiment of the present invention;

[0022] Figure 4 is a flowchart of a manufacturing method of a gallium nitride HEMT device on a substrate in an embodiment of the present invention;

[0023] Figure 5 It is a schematic diagram of the process of preparing the SiO2 discontinuous layer in the manufacturing method of a gallium nitride HEMT device on a substrate in an embodiment of the present invention;

[0024] Figure 6 It shows the surface topography shown by an atomic force microscope (AFM).

[0025] Reference numerals of the above drawings: 1. Substrate; 2. AlN nucleation layer; 3. AlGaN layer; 4. Buffer layer; 5. High-carbon GaN layer; 6. Low-carbon GaN channel layer; 7. AlGaN barrier layer; 8. Capping layer; 9. SiO2 mask; 10. SiO2 continuous layer; 11. SiO2 discontinuous layer. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] The common epitaxial layer structure in the prior art is as Figure 1 shown. From bottom to top, it sequentially includes a substrate 1 (such as a silicon substrate 1), an aluminum nitride (AlN) nucleation layer, an AlGaN layer 3, where the AlGaN layer 3 is composed of one or more AlGaN with different aluminum contents, a buffer layer 4 (Buffer layer), where the buffer layer 4 is composed of a superlattice buffer layer 4 formed by alternating AlN and AlGaN periodically. Above the buffer layer 4 are sequentially a high-carbon GaN layer 5, a low-carbon GaN channel layer 6, an AlGaN barrier layer 7, and a capping layer 8. In the above structure, due to the large lattice mismatch between GaN / AlN and silicon in the substrate 1, a high density of dislocations will be generated during the epitaxial growth process, and these dislocations will penetrate through the epitaxial growth to the surface of the epitaxial layer all the time, resulting in a high density of penetrating dislocations in the low-carbon GaN channel layer 6, which is crucial for the performance of the gallium nitride high electron mobility transistor device, as well as in the subsequent AlGaN barrier layer 7 and capping layer 8. These dislocations will reduce the device performance and reliability.

[0028] The optimized epitaxial layer structure in the prior art is as Figure 2As shown, the difference from the first type is that a GaN layer is grown above the buffer layer 4 first, and then a periodic and regular silicon dioxide SiO2 mask 9 is formed on this layer through techniques such as deposition - lithography - etching. Subsequently, a low - carbon GaN channel layer 6, and subsequent AlGaN barrier layer 7 and capping layer 8 are grown on the patterned epitaxial structure. Before growing the low - carbon GaN channel layer 6 in the above - optimized epitaxial structure, a periodic SiO2 mask 9 is formed on the GaN layer to block the continuous upward extension of threading dislocations, which can greatly reduce the dislocation density of the subsequent low - carbon GaN channel layer 6 and the layers above. However, the second epitaxial structure has the following two major drawbacks: 1. Additional deposition - lithography - etching steps are required to form the periodic SiO2 mask 9, which increases the cost; 2. Introducing the SiO2 mask 9 causes an interruption in epitaxial growth, leading to interface problems. At the same time, the difficulty of secondary epitaxial growth of GaN on the SiO2 mask 9 is relatively high, and there will be a series of problems such as the inability of the epitaxial layer to merge smoothly and the appearance of holes in the epitaxy.

[0029] To solve the above problems, as Figure 3 shown, an epitaxial layer of a gallium nitride HEMT device on a substrate in this embodiment includes a substrate 1, and a SiO2 discontinuous layer 11, an AlN nucleation layer 2, an AlGaN layer 3, a buffer layer 4, a high - carbon GaN layer 5, a low - carbon GaN channel layer 6, an AlGaN barrier layer 7, and a capping layer 8 that are sequentially stacked along the longitudinal direction on the surface of the substrate 1. Among them, randomly irregular triangle - like shapes are distributed on the surface of the SiO2 discontinuous layer 11, which can expose part of the substrate 1 on its surface, so that part of the AlN nucleation layer 2 can contact the substrate 1 exposed on the surface of the SiO2 discontinuous layer 11, and the rest of the AlN nucleation layer 2 is continuous. That is, the bottom end of the SiO2 discontinuous layer 11 is connected to the substrate 1, so that the substrate 1 is exposed on the surface, and the surface of the SiO2 discontinuous layer 11 is randomly pieced together by triangles with different sizes and dimensions, so that the surface shape of the SiO2 discontinuous layer 11 is irregular. Preferably, the substrate 1 is a silicon substrate 1. Of course, in other alternative embodiments, the substrate 1 can also be a substrate composed of several materials such as a single - crystal silicon thin film on an insulator. Preferably, the thickness of the buffer layer 4 is 0.3μm - 15μm, the thickness of the AlN nucleation layer 2 is 30nm - 1500nm, and the thickness of the AlGaN layer 3 is 25nm - 400nm.

[0030] In this embodiment, taking the substrate 1 as a silicon substrate 1 as an example, before the epitaxial growth starting from the AlN nucleation layer 2, several nanometer-thick randomly distributed SiO2 discontinuous layers 11 (SiO2 discontinuous layer) are first formed on the silicon substrate 1, that is, the silicon substrate 1 is discontinuously covered by SiO2 thin layers, and only a part of the silicon substrate 1 is exposed on the surface. In this way, when the epitaxial growth starts, AlN first starts to deposit only on the surface where the silicon substrate 1 is exposed to form a plurality of spaced-apart AlN islands. Subsequently, the AlN continues to grow epitaxially to gradually merge the AlN islands to form a continuous AlN nucleation layer 2. Such a growth mode reduces the density of threading dislocations generated by the large lattice mismatch between AlN and Si on the silicon substrate 1. At the same time, it accelerates the turning and annihilation of threading dislocations during the subsequent epitaxial growth process, effectively reducing the dislocation density of the subsequent low-carbon GaN channel layer 6 and other upper layers, and does not require additional deposition-lithography-etching steps, greatly reducing the cost. Through the above process, randomly and irregularly distributed SiO2 discontinuous layers 11 can be generated, that is, the above process can obtain such random results, rather than the regular periodic shapes in the prior art.

[0031] With the above structure, the substrate 1 is discontinuously covered by randomly irregular SiO2 thin layers, and only a part of the substrate 1 is exposed on the surface. Growing the HEMT structure on such a substrate 1 reduces the density of GaN threading dislocations in the high-carbon GaN layer 5 and the low-carbon GaN channel layer 6. The performance and reliability of the HEMT power device prepared using such an epitaxial structure with a low dislocation density are improved. In addition, by directly forming the SiO2 discontinuous layer 11 on the substrate 1, no additional deposition-lithography-etching steps are required, effectively reducing the cost. At the same time, the thickness of the SiO2 discontinuous layer 11 can be made very thin, with little impact on the subsequent epitaxial AlN nucleation layer 2 and the entire HEMT structure, a large epitaxial window, and a high epitaxial production yield.

[0032] As Figures 4 to 5 shown, this embodiment also provides a manufacturing method of a gallium nitride HEMT device on a substrate, including the following steps:

[0033] Prepare the substrate 1. The substrate 1 can be a silicon (Si) substrate 1, or a substrate 1 composed of several materials such as a single-crystalline silicon thin film on insulator (Silicon On Insulator, abbreviated as SOI). The thickness of the substrate 1 is 300 μm - 3000 μm. When using the silicon substrate 1, its resistivity is 0.001 Ω·cm to 5000 Ω·cm.

[0034] A continuous SiO2 layer 10 is formed on the surface of the substrate 1. Preferably, its thickness ranges from 0.5 nm to 5 nm. The formation method can be natural oxidation of the surface of the silicon substrate 1 exposed to air, or thermal oxidation, etc. The continuous SiO2 layer 10 completely covers the surface of the silicon substrate 1.

[0035] Remove a part of the continuous SiO2 layer 10 to form a discontinuous SiO2 layer 11. Treat the continuous SiO2 layer 10 in a metalorganic chemical vapor deposition (MOCVD) furnace, or use hydrofluoric acid to etch a part of the continuous SiO2 layer 10 so that a part of the surface of the continuous SiO2 layer 10 is removed and the underlying substrate 1 is exposed, while the remaining SiO2 still remains, presenting a surface topography as shown by Figure 6 an atomic force microscope (AFM). Among them, Figure 6 the results in show that the rough areas with higher height are the discontinuous SiO2 layer 11, and the remaining flatter areas with lower height are the exposed silicon substrate 1. The surface of the remaining discontinuous SiO2 layer 11 presents a random and irregular, triangular-like shape, with a thickness of 0.5 nm to 5 nm and a coverage rate of 5% to 90% covering the surface of the silicon substrate 1. That is, the bottom end of the discontinuous SiO2 layer 11 communicates with the substrate 1, so that the surface of the substrate 1 is exposed, and the surface of the discontinuous SiO2 layer 11 is composed of triangles of various sizes and dimensions, so that the surface shape of the discontinuous SiO2 layer 11 is irregular. Thus, it is different from the periodic and regular-shaped surfaces formed by traditional etching and other methods.

[0036] An AlN nucleation layer 2 is epitaxially grown on the surface of the discontinuous SiO2 layer 11. AlN first starts to deposit only on the surface where the silicon substrate 1 is exposed to form a plurality of mutually spaced AlN islands. Subsequently, AlN continues to grow epitaxially so that the AlN islands gradually merge to form a continuous AlN nucleation layer 2. The epitaxial growth can be completed using a metalorganic chemical vapor deposition (MOCVD) device, and its thickness is 30 nm to 1500 nm.

[0037] An AlGaN layer 3, a buffer layer 4, a high-carbon GaN layer 5, a low-carbon GaN channel layer 6, an AlGaN barrier layer 7, and a cap layer 8 are sequentially epitaxially grown along the longitudinal direction on the surface of the AlN nucleation layer 2. Among them, the buffer layer 4 is composed of a superlattice buffer layer 4 formed by alternately and periodically forming AlN and AlGaN. According to specific circumstances, it may not include this periodic superlattice buffer layer 4 and be directly replaced by an AlGaN buffer layer 4. The superlattice buffer layer 4 can be doped with elements such as carbon and iron to increase the resistivity of this layer. The doping concentration of the doped elements is between 5×10 17 cm -3 and 5×10 19 cm-3 Between them, the thickness range of the superlattice buffer layer 4 is from 0.3 μm to 15 μm. Above the buffer layer 4 are, in sequence, a high-carbon GaN layer 5 (carbon concentration greater than 10 18 cm -3 ), a low-carbon GaN channel layer 6 (carbon concentration less than 10 18 cm -3 ), an AlGaN barrier layer 7, and a capping layer 8. The material of the capping layer 8 varies depending on whether the device is enhancement-mode or depletion-mode. The capping layer 8 of the enhancement-mode HEMT is usually magnesium-doped gallium nitride, while the capping layer 8 of the depletion-mode HEMT may be silicon nitride or undoped gallium nitride intentionally.

[0038] It should be noted that in the above-mentioned epitaxial growth process, metalorganic chemical vapor deposition or molecular beam epitaxy methods can be used.

[0039] In this embodiment, taking the substrate 1 as a silicon substrate 1 as an example, before the epitaxial growth starting from the AlN nucleation layer 2, several nanometers-thick randomly distributed SiO2 discontinuous layers 11 (SiO2 discontinuous layer) are first formed on the silicon substrate 1, that is, the silicon substrate 1 is discontinuously covered by SiO2 thin layers, and only part of the silicon substrate 1 is exposed on the surface. In this way, when the epitaxial growth starts, AlN first starts to deposit only on the surface where the silicon substrate 1 is exposed to form a plurality of spaced-apart AlN islands. Subsequently, the AlN continues to grow epitaxially so that the AlN islands gradually merge to form a continuous AlN nucleation layer 2. Such a growth mode reduces the density of threading dislocations generated by the large lattice mismatch between AlN and Si on the silicon substrate 1, and at the same time accelerates the turning and annihilation of threading dislocations during the subsequent epitaxial growth process, effectively reducing the dislocation density of the subsequent low-carbon GaN channel layer 6 and other upper layers, and also does not require additional deposition-lithography-etching steps, greatly reducing the cost.

[0040] With the above structure, the substrate 1 is discontinuously covered by randomly irregular SiO2 thin layers, and only part of the substrate 1 is exposed on the surface. Growing the HEMT structure on such a substrate 1 reduces the density of GaN threading dislocations in the high-carbon GaN layer 5 and the low-carbon GaN channel layer 6. The performance and reliability of the HEMT power device prepared using such a low-dislocation-density epitaxial structure are improved. In addition, by directly forming the SiO2 discontinuous layer 11 on the substrate 1, additional deposition-lithography-etching steps are not required, effectively reducing the cost. At the same time, the thickness of the SiO2 discontinuous layer 11 can be made very thin, having little impact on the subsequent epitaxial growth of the AlN nucleation layer 2 and the entire HEMT structure, with a large epitaxial window and a high epitaxial production yield.

[0041] In the present invention, specific embodiments are used to illustrate the principle and implementation manner of the present invention. The description of the above embodiments is only for helping to understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. An epitaxial layer of a gallium nitride HEMT device on a substrate, characterized in that, It includes a substrate, and a discontinuous SiO2 layer, an AlN nucleation layer, an AlGaN layer, a buffer layer, a high-carbon GaN layer, a low-carbon GaN channel layer, an AlGaN barrier layer, and a cap layer that are sequentially stacked longitudinally on the surface of the substrate. Among them, the surface of the discontinuous SiO2 layer is distributed with randomly irregular triangular shapes, which can expose part of the substrate on its surface.

2. The epitaxial layer of a gallium nitride HEMT device on a substrate according to claim 1, wherein The substrate is a silicon substrate or a single-crystalline silicon thin film on insulator.

3. The epitaxial layer of a gallium nitride HEMT device on a substrate according to claim 1, wherein The buffer layer is a superlattice buffer layer formed by alternately and periodically arranging AlN and AlGaN.

4. The epitaxial layer of a gallium nitride HEMT device on a substrate according to claim 1, characterized in that, The thickness of the buffer layer is 0.3 μm - 15 μm, the thickness of the AlN nucleation layer is 30 nm - 1500 nm, and the thickness of the AlGaN layer is 25 nm - 400 nm.

5. A manufacturing method of a gallium nitride HEMT device on a substrate, characterized in that, It includes the following steps: Prepare a substrate; Form a continuous SiO2 layer on the surface of the substrate; Remove part of the continuous SiO2 layer to form a discontinuous SiO2 layer; Epitaxially grow an AlN nucleation layer on the discontinuous SiO2 layer; Epitaxially grow and form an AlGaN layer, a buffer layer, a high-carbon GaN layer, a low-carbon GaN channel layer, an AlGaN barrier layer, and a cap layer sequentially longitudinally on the surface of the AlN nucleation layer.

6. The manufacturing method of a gallium nitride HEMT device on a substrate according to claim 5, wherein The metal organic chemical vapor deposition or molecular beam epitaxy method is adopted during the epitaxial growth process.

7. The manufacturing method of a gallium nitride HEMT device on a substrate according to claim 5, characterized in that, In the step of "preparing a substrate", the thickness of the substrate is 300 μm - 3000 μm, and the resistivity is 0.001 Ω·cm - 5000 Ω·cm.

8. The manufacturing method of a gallium nitride HEMT device on a substrate according to claim 5, characterized in that, In the step of "forming a continuous SiO2 layer on the surface of the substrate", the continuous SiO2 layer completely covers the surface of the substrate, and the thickness of the continuous SiO2 layer is 0.5 nm - 5 nm.

9. The manufacturing method of a gallium nitride HEMT device on a substrate according to claim 5, characterized in that, In the step of "removing part of the continuous SiO2 layer to form a discontinuous SiO2 layer", it includes the following steps: Process the continuous SiO2 layer in a metal organic chemical vapor deposition (MOCVD) furnace, or use hydrofluoric acid to etch part of the continuous SiO2 layer, so that part of the continuous SiO2 layer on the surface is removed and the substrate below it is exposed, and the surface of the remaining discontinuous SiO2 layer is distributed with randomly irregular triangular shapes.

10. The manufacturing method of a gallium nitride HEMT device on a substrate according to claim 9, characterized in that, In the step of "epitaxially growing an AlN nucleation layer on the discontinuous SiO2 layer", it includes the following steps: AlN first starts to deposit only on the surface where the substrate is exposed to form multiple mutually spaced AlN islands; AlN continues to epitaxially grow to gradually merge the AlN islands to form a continuous AlN nucleation layer, and the thickness of this AlN nucleation layer is 30 nm - 1500 nm.

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