A GaN HEMT device with a high-resistance buffer layer and a preparation method thereof

Abstract

The present invention discloses a GaN HEMT device with a high-resistance buffer layer and a preparation method thereof. The device includes a substrate, an AlN nucleation layer, a stress regulation layer, a high-resistance buffer layer, a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer, and a GaN cap layer which are sequentially arranged from bottom to top. Among them, the high-resistance buffer layer sequentially includes a Fe-doped GaN buffer layer, a hexagonal BN buffer layer, and a C-doped GaN buffer layer from bottom to top. The upper surface of the GaN cap layer is provided with a source electrode, a drain electrode, and a gate electrode which are spaced from each other. The source electrode and the drain electrode form an ohmic contact with the AlGaN barrier layer; the gate electrode forms a Schottky contact with the AlGaN barrier layer. The present invention utilizes the high-resistance buffer layer to not only achieve the high-resistance characteristic of the buffer layer, but also prevent Fe from entering the GaN channel layer and affecting the overall performance of the device, and can also suppress the occurrence of current collapse phenomenon.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor materials and devices, and particularly relates to a GaN HEMT device with a high-resistance buffer layer and a preparation method thereof. Background Art

[0002] With the development of technology, high-performance and high-efficiency semiconductor power electronic devices are particularly important in today's society. Due to the limitations of the material itself, it is difficult to significantly improve the performance and efficiency of traditional Si-based semiconductor power electronic devices. Wide-bandgap semiconductors represented by GaN are very suitable for preparing high-performance and high-efficiency power electronic devices because of their excellent properties such as large bandgap width, high breakdown field strength, and high electron mobility. GaN heterojunction field effect transistors (HFETs) are often referred to as GaN high electron mobility transistors (HEMTs). However, as the operating voltage and frequency of GaN HEMTs become higher and higher, problems such as device leakage and reliability have become key issues hindering their further development. It has been found that the key to solving problems such as device leakage in a high-voltage and high-frequency operating environment lies in a high-quality and high-resistance buffer layer.

[0003] Many studies on high-resistance buffer layers have been reported. Due to the reasons of the GaN material growth process itself, a relatively high concentration of background electron concentration will inevitably be introduced. Therefore, to achieve high-resistance GaN materials, it is necessary to eliminate their background electrons. The most commonly used method in academia and industry is to dope and compensate for the background electrons introduced during the growth process. The two most commonly used elements to achieve a high-resistance GaN buffer layer by doping are C and Fe. However, there are non-negligible problems whether using C doping or Fe doping. C is an amphoteric impurity in GaN. It can not only act as an acceptor but also exist in the form of a donor. If the growth conditions are not precisely controlled, it is very likely to introduce C in the form of a donor in GaN, resulting in a further reduction in the resistance of the material. Moreover, the presence of a high concentration of C in the GaN buffer layer will cause a serious current collapse phenomenon, which will severely restrict the characteristics of the device in high-power and high-frequency scenarios. During the epitaxial growth process of GaN materials, Fe atoms have a memory effect due to their extremely high mobility and low thermal desorption rate. If the Fe atoms in the buffer layer diffuse into the channel region, the Fe atoms, as deep-level acceptors, will capture the electrons in the 2DEG, reducing its surface density. And due to the extremely large atomic radius of Fe, the electron scattering probability will also increase significantly, and the mobility of the 2DEG will decrease accordingly. Therefore, how to obtain a high-resistance buffer layer without affecting the overall performance of the device has become the focus of research on GaN high-resistance buffer layers. Summary of the Invention

[0004] To overcome the deficiencies of the existing solutions for implementing a high-resistance buffer layer by separately doping with C or Fe, the present invention provides a GaN HEMT device with a high-resistance buffer layer and a preparation method thereof. The technical problems to be solved by the present invention are achieved through the following technical solutions:

[0005] One aspect of the present invention provides a GaN HEMT device with a high-resistance buffer layer, which includes a substrate, an AlN nucleation layer, a stress regulation layer, a high-resistance buffer layer, a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer, and a GaN cap layer arranged in sequence from bottom to top. Among them,

[0006] The high-resistance buffer layer sequentially includes a GaN buffer layer doped with Fe, a hexagonal BN buffer layer, and a GaN buffer layer doped with C from bottom to top;

[0007] On the upper surface of the GaN cap layer, there are spaced source electrodes, drain electrodes, and gate electrodes. The source electrode and the drain electrode respectively form ohmic contacts with the AlGaN barrier layer; the gate electrode forms a Schottky contact with the AlGaN barrier layer.

[0008] In an embodiment of the present invention, the substrate is Si with a (111) plane, SiC with a (001) plane, or sapphire with a (001) plane.

[0009] In an embodiment of the present invention, the stress regulation layer is an AlGaN buffer layer with a gradually changing Al composition or an AlN / GaN superlattice buffer layer, and the gradually changing range of the Al composition of the AlGaN buffer layer is 0 - 100%.

[0010] In an embodiment of the present invention, the thickness of the high-resistance buffer layer is 300 - 2500 nm. Among them, the thickness of the GaN buffer layer doped with Fe is 100 - 1000 nm, and the doping concentration of Fe is 1×10 18 -1×10 19 cm -3 ; the thickness of the hexagonal BN buffer layer is 100 - 500 nm; the thickness of the GaN buffer layer doped with C is 100 - 1000 nm, and the doping concentration of C is 1×10 17 -1×10 18 cm -3 .

[0011] In an embodiment of the present invention, the Fe concentration of the GaN channel layer is less than or equal to 1×10 16 cm -3 .

[0012] Another aspect of the present invention provides a method for fabricating a GaN HEMT device with a high-resistance buffer layer, which is used to fabricate a GaN HEMT device with a high-resistance buffer layer described in any one of the above embodiments. The fabrication method includes:

[0013] S1: Grow an AlN nucleation layer on the upper surface of the substrate;

[0014] S2: Grow a stress regulation layer on the upper surface of the AlN nucleation layer;

[0015] S3: Grow a high-resistance buffer layer on the upper surface of the stress regulation layer. The high-resistance buffer layer sequentially includes an Fe-doped GaN buffer layer, a hexagonal BN buffer layer, and a C-doped GaN buffer layer from bottom to top;

[0016] S4: Grow a GaN channel layer on the upper surface of the high-resistance buffer layer;

[0017] S5: Grow an AlN insertion layer on the upper surface of the GaN channel layer;

[0018] S6: Grow an AlGaN barrier layer on the upper surface of the AlN insertion layer;

[0019] S7: Grow a GaN cap layer on the upper surface of the AlGaN barrier layer;

[0020] S8: Fabricate spaced-apart source electrodes, drain electrodes, and gate electrodes on the upper surface of the GaN cap layer.

[0021] In an embodiment of the present invention, S1 includes:

[0022] Grow an AlN nucleation layer on the upper surface of the substrate. The substrate is (111)-plane Si, (001)-plane SiC, or (001)-plane sapphire, with a size of 2 - 8 inches; the growth temperature of the nucleation layer is 1000 - 1100 °C, the growth pressure is 40 - 100 torr, and the growth thickness is 200 - 300 nm.

[0023] In an embodiment of the present invention, S3 includes:

[0024] Grow an Fe-doped GaN buffer layer with a thickness of 100 - 1000 nm on the upper surface of the stress regulation layer. The Fe source is Cp2Fe, the Cp2Fe flow rate is 100 - 600 sccm, the growth temperature is 1000 - 1100 °C, and the growth pressure is 40 - 100 torr;

[0025] Grow a hexagonal BN buffer layer with a thickness of 100 - 500 nm on the upper surface of the Fe-doped GaN buffer layer. The boron source is BCl3, the growth temperature is 1100 - 1500 °C, and the growth pressure is 1 - 20 torr;

[0026] A C-doped GaN buffer layer with a thickness of 100 - 1000 nm is grown on the upper surface of the hexagonal BN buffer layer by in-situ doping, with a growth temperature of 500 - 1000 °C and a growth pressure of 40 - 100 torr.

[0027] In one embodiment of the present invention, the S8 includes:

[0028] A source electrode, a drain electrode, and a gate electrode are respectively prepared on the GaN cap layer. Among them, the source electrode and the drain electrode respectively form ohmic contacts with the AlGaN barrier layer; the gate electrode forms a Schottky contact with the AlGaN barrier layer.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] The GaN HEMT device with a high-resistance buffer layer of the present invention enables the realization of a high-resistance buffer layer without affecting the overall performance of the device. The important technologies include: first, a Fe-doped GaN buffer layer is grown on the stress regulation layer at a high temperature, then a hexagonal BN buffer layer is grown on the Fe-doped GaN buffer layer, and finally a C-doped GaN buffer layer is grown on the hexagonal BN buffer layer at a low temperature. The radius of the Fe atom is 15% larger than that of the Ga atom, 38% larger than that of the B atom, and 126% larger than that of the C atom. Therefore, the hexagonal BN buffer layer will apply compressive stress to the Fe-doped GaN buffer layer, and the C-doped GaN buffer layer will apply compressive stress to the hexagonal BN buffer layer. The compressive stress will make the Fe atoms on the growth surface in an unstable state, thereby accelerating the desorption of Fe from the growth surface, and finally achieving the effect of suppressing the memory effect and segregation of Fe.

[0031] Due to the extremely large bandgap width of hexagonal BN, the material itself is highly resistive. The C-doped GaN buffer layer is grown at a low temperature. At a lower temperature, Fe atoms cannot obtain enough energy to migrate upward, and the memory effect of Fe is further suppressed. Due to the presence of a high concentration of Fe in the buffer layer, the concentration of C can be appropriately reduced, thereby suppressing the current collapse phenomenon of the device at a high C concentration. Therefore, the above-mentioned high-resistance buffer layer can not only achieve the high-resistance characteristics of the buffer layer, but also prevent Fe from entering the GaN channel layer and affecting the overall performance of the device, and can also suppress the occurrence of the current collapse phenomenon.

[0032] The present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0033] Figure 1 It is a schematic structural diagram of a GaN HEMT device with a high-resistance buffer layer provided by an embodiment of the present invention;

[0034] Figure 2 It is a flowchart of a preparation method of a GaN HEMT device with a high-resistance buffer layer provided by an embodiment of the present invention;

[0035] Figures 3a to 3h It is a schematic diagram of the preparation process of a GaN HEMT device with a high-resistance buffer layer provided by an embodiment of the present invention. Specific embodiments

[0036] In order to further elaborate on the technical means and advantages adopted by the present invention to achieve the intended invention purpose, the following, in combination with the accompanying drawings and specific embodiments, details a GaN HEMT device with a high-resistance buffer layer and its preparation method according to the present invention.

[0037] The foregoing and other technical contents, features and advantages of the present invention can be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of specific embodiments, a more in-depth and specific understanding of the technical means and advantages adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are only for reference and illustration purposes and are not used to limit the technical solutions of the present invention.

[0038] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant is intended to cover non-exclusive inclusion, so that an article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the article or device including the said element.

[0039] Embodiment 1

[0040] Please refer to Figure 1 , Figure 1It is a schematic structural diagram of a GaN HEMT device with a high-resistance buffer layer provided by an embodiment of the present invention. The GaN HEMT device includes a substrate 1, an AlN nucleation layer 2, a stress regulation layer 3, a high-resistance buffer layer 4, a GaN channel layer 5, an AlN insertion layer 6, an AlGaN barrier layer 7, and a GaN cap layer 8 arranged in sequence from bottom to top. Among them, the high-resistance buffer layer 4 includes a Fe-doped GaN buffer layer, a hexagonal BN buffer layer, and a C-doped GaN buffer layer in sequence from bottom to top; on the upper surface of the GaN cap layer 8, there are spaced source electrodes 9, drain electrodes 10, and gate electrodes 11. The source electrodes 9 and the drain electrodes 10 form ohmic contacts with the AlGaN barrier layer 7; the gate electrodes 11 form Schottky contacts with the AlGaN barrier layer 7.

[0041] The substrate 1 of this embodiment is (111)-plane Si, (001)-plane SiC, or (001)-plane sapphire, with a size of 2 - 8 inches; among them, when the substrate 1 is Si, the AlN nucleation layer 2 grows on the (111) surface of the substrate 1, when the substrate 1 is SiC, the AlN nucleation layer 2 grows on the (001) surface of the substrate 1, and when the substrate 1 is sapphire, the AlN nucleation layer 2 grows on the (001) surface of the substrate 1. The stress regulation layer 3 is an AlGaN buffer layer with a gradually changing Al component or an AlN / GaN superlattice buffer layer, and the range of the gradually changing Al component of the AlGaN buffer layer is 0 - 100%. The epitaxial growth direction of this device structure is the

[001] direction of the epitaxial nitride, and the crystal plane corresponding to the epitaxial growth direction is the polar plane (001) plane.

[0042] Furthermore, the high-resistance buffer layer 4 is composed of a Fe-doped GaN buffer layer, a hexagonal BN buffer layer, and a C-doped GaN buffer layer, with a thickness of 300 - 2500 nm. Among them, the thickness of the Fe-doped GaN buffer layer is 100 - 1000 nm, and the doping concentration of Fe is 1×10 18 -1×10 19 cm -3 ; the thickness of the hexagonal BN buffer layer is 100 - 500 nm; the thickness of the C-doped GaN buffer layer is 100 - 1000 nm, and the doping concentration of C is 1×10 17 -1×10 18 cm -3 .

[0043] An embodiment of the present invention provides a GaN HEMT device with a high-resistance buffer layer, enabling the realization of the high-resistance buffer layer 4 without affecting the overall performance of the device. Specifically, first, a Fe-doped GaN buffer layer is grown on the stress regulation layer at a high temperature, then a hexagonal BN buffer layer is grown on the Fe-doped GaN buffer layer, and finally a C-doped GaN buffer layer is grown on the hexagonal BN buffer layer at a low temperature. The radius of the Fe atom is 15% larger than that of the Ga atom, 38% larger than that of the B atom, and 126% larger than that of the C atom. Therefore, the hexagonal BN buffer layer applies compressive stress to the Fe-doped GaN buffer layer, and the C-doped GaN buffer layer applies compressive stress to the hexagonal BN buffer layer. The compressive stress makes the Fe atoms on the growth surface in an unstable state, thereby accelerating the desorption of Fe from the growth surface, and finally achieving the effect of suppressing the memory effect and segregation of Fe.

[0044] Due to the extremely large bandgap width of hexagonal BN, the material itself is high-resistance. The C-doped GaN buffer layer is grown at a low temperature. At a lower temperature, Fe atoms cannot obtain enough energy to migrate upward, and the memory effect of Fe is further suppressed. Due to the presence of a high concentration of Fe in the buffer layer, the concentration of C can be appropriately reduced, thereby suppressing the current collapse phenomenon of the device under a high C concentration. Therefore, the high-resistance buffer layer 4 described above can not only achieve the high-resistance characteristic of the buffer layer, but also prevent Fe from entering the GaN channel layer, affecting the overall performance of the device, and can also suppress the occurrence of the current collapse phenomenon.

[0045] Embodiment Two

[0046] Based on the above embodiment, this embodiment provides a preparation method of a GaN HEMT device with a high-resistance buffer layer. The metal organic chemical vapor deposition (MOCVD) equipment is used, where the nitrogen source is NH3, the group III source is trimethylgallium, boron trichloride, and trimethylaluminum, the Fe source is Cp2Fe, and the carrier gas is N2 or H2. Please refer to Figure 2 and Figures 3a to 3h , and the preparation method of this embodiment includes:

[0047] S1: Grow an AlN nucleation layer 2 on the upper surface of the substrate 1, as Figure 3a shown.

[0048] An AlN nucleation layer 2 is grown on a substrate 1. The substrate 1 is Si with a (111) plane, SiC with a (001) plane, or sapphire with a (001) plane, and has a size of 2 - 8 inches. The growth temperature of the AlN nucleation layer 2 is 1000 - 1100 °C, the growth pressure is 40 - 100 torr, and the growth thickness is 200 - 300 nm. The function of the AlN nucleation layer 2 is to provide nucleation centers with the same orientation as the substrate 1, release the mismatch stress generated by the lattice mismatch between the subsequently grown GaN and the substrate 1 and the thermal stress generated by the mismatch of the thermal expansion coefficient, and provide a flat nucleation surface for further epitaxial growth, reduce the contact angle of its nucleation growth, enable the island-grown GaN grains to connect into a plane at a smaller thickness, and transform into two-dimensional growth.

[0049] S2: A stress regulation layer 3 is grown on the AlN nucleation layer 2, such as Figure 3b shown.

[0050] A stress regulation layer 3 is grown on the AlN nucleation layer 2. The stress regulation layer 3 is an AlGaN buffer layer with a gradually changing Al composition or an AlN / GaN superlattice buffer layer. The range of the gradual change in the Al composition of the AlGaN buffer layer is 0 - 100%, and the total thickness is 1 - 3 μm. This stress regulation layer 3 is used to regulate the large mismatch stress generated between the epitaxial layer and the substrate due to lattice mismatch and thermal mismatch.

[0051] S3: A high-resistance buffer layer 4 is grown on the upper surface of the stress regulation layer 3. The high-resistance buffer layer 4 sequentially includes a Fe-doped GaN buffer layer, a hexagonal BN buffer layer, and a C-doped GaN buffer layer from bottom to top; such as Figure 3c shown.

[0052] First, a Fe-doped GaN buffer layer is grown at a high temperature. The Fe source is Cp2Fe, the flow rate of Cp2Fe is 100 - 600 sccm, the growth temperature is 1000 - 1100 °C, the growth pressure is 40 - 100 torr, and the growth thickness is 100 - 1000 nm. Then, a hexagonal BN buffer layer is grown on the Fe-doped GaN buffer layer at a high temperature and low pressure. The boron source is BCl3, the growth temperature is 1100 - 1500 °C, the growth pressure is 1 - 20 torr, and the growth thickness is 100 - 500 nm. Finally, a C-doped GaN buffer layer is grown on the hexagonal BN buffer layer at a low temperature by means of low-temperature in-situ doping. The growth temperature is 500 - 1000 °C, the growth pressure is 40 - 100 torr, and the growth thickness is 100 - 1000 nm. The hexagonal BN buffer layer exerts compressive stress on the Fe-doped GaN buffer layer, and the C-doped GaN buffer layer exerts compressive stress on the hexagonal BN buffer layer. The compressive stress makes the Fe atoms on the growth surface in an unstable state, thereby accelerating the desorption of Fe from the growth surface, and finally achieving the effect of suppressing the memory effect and segregation of Fe.

[0053] The high-resistance buffer layer 4 has a sandwich structure, and its specific implementation method and principle are as follows: The radius of Fe atoms is 15% larger than that of Ga atoms, 38% larger than that of B atoms, and 126% larger than that of C atoms. Therefore, the hexagonal BN buffer layer exerts compressive stress on the Fe-doped GaN buffer layer, and the C-doped GaN buffer layer exerts compressive stress on the hexagonal BN buffer layer. The compressive stress makes the Fe atoms on the growth surface in an unstable state, thereby accelerating the desorption of Fe from the growth surface, and finally achieving the effect of suppressing the memory effect and segregation of Fe. Due to the extremely large bandgap of hexagonal boron nitride, the material itself is high-resistance. The C-doped GaN buffer layer is grown at a low temperature. At a lower temperature, Fe atoms cannot obtain enough energy to migrate upward, and the memory effect of Fe is further suppressed. Due to the presence of a high concentration of Fe in the buffer layer, the concentration of C can be appropriately reduced, thereby suppressing the current collapse phenomenon of the device at a high C concentration. Therefore, the high-resistance buffer layer 4 described above can not only achieve the high-resistance characteristics of the buffer layer, but also prevent Fe from entering the GaN channel layer and affecting the overall performance of the device, and can also suppress the occurrence of the current collapse phenomenon.

[0054] S4: Grow the GaN channel layer 5 on the high-resistance buffer layer 4, as Figure 3d shown.

[0055] Grow the GaN channel layer 5 on the high-resistance buffer layer 4. The growth temperature of the GaN channel layer 5 is 1000 - 1100 °C, the growth pressure is 40 - 100 torr, and the growth thickness is 100 - 300 nm; Since the two-dimensional electron gas is on one side of the GaN channel layer, the GaN channel layer 5 should have a very high crystal quality and is usually not doped to reduce the scattering of the two-dimensional electron gas; The Fe concentration of the GaN channel layer 5 should be less than or equal to 1×10 16 cm -3 .

[0056] S5: Grow the AlN insertion layer 6 on the GaN channel layer 5, as Figure 3e shown.

[0057] Grow the AlN insertion layer 6 on the GaN channel layer 5. The thickness of the AlN insertion layer 6 is 1 nm, the growth pressure is 40 - 100 torr, and the growth temperature is 1000 - 1100 °C; The insertion layer 6 is grown on the GaN channel layer 5, and its function is to improve the effective conduction band offset between the AlGaN barrier layer 7 and the GaN channel layer 5, thereby increasing the two-dimensional electron gas surface density; On the other hand, the AlN insertion layer 6 can suppress the scattering of the part of the two-dimensional electron gas that penetrates into the AlGaN barrier layer 7, thereby improving the mobility of the two-dimensional electron gas.

[0058] S6: Grow the AlGaN barrier layer 7 on the AlN insertion layer 6, asFigure 3f shown.

[0059] An AlGaN barrier layer 7 is grown on the AlN insertion layer 6, with the Al component varying in the range of 0-50%, the growth thickness being 10-40nm, the growth pressure being 40-100torr, and the growth temperature being 1000-1100°C; since the AlGaN barrier layer 7 has both large spontaneous polarization and piezoelectric polarization effects, a large amount of positive polarization charge will be generated at the interface between the AlGaN barrier layer and the channel layer, and the polarization positive charge can attract electrons, thereby forming two-dimensional electrons.

[0060] S7: growing a GaN cap layer 8 on the AlGaN barrier layer 7, such as Figure 3g shown.

[0061] A GaN cap layer 8 is grown on the AlGaN barrier layer, wherein the GaN cap layer 8 has a growth thickness of 1-3 nm, a growth pressure of 40-100 torr, and a growth temperature of 1000-1100° C. The GaN cap layer 8 is grown on the AlGaN barrier layer 7, and its function is to improve the mobility of the two-dimensional electron gas, increase the Schottky contact barrier on the AlGaN / GaN heterojunction structure, and thus significantly reduce the gate leakage current;

[0062] S8: Prepare a source electrode 9, a drain electrode 10, and a gate electrode 11 on the GaN cap layer 8, respectively. Figure 3h shown.

[0063] A source electrode 9, a drain electrode 10 and a gate electrode 11 are respectively prepared on the GaN cap layer 8, and the metal of the source electrode 9 and the metal of the drain electrode 10 form an ohmic contact with the AlGaN barrier layer 7; the metal of the gate electrode 11 forms a Schottky contact with the AlGaN barrier layer. So far, the process flow of the GaN HEMT device with a high-resistance buffer layer of this embodiment has been completed.

[0064] The GaN HEMT device with a high-resistance buffer layer prepared by the method of the embodiment of the present invention can not only realize the high-resistance characteristics of the buffer layer, but also prevent Fe from entering the GaN channel layer 5 and affecting the overall performance of the device, and can also suppress the occurrence of current collapse.

[0065] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A GaN HEMT device with a high-resistance buffer layer, characterized in that, It includes a substrate (1), an AlN nucleation layer (2), a stress regulation layer (3), a high-resistance buffer layer (4), a GaN channel layer (5), an AlN insertion layer (6), an AlGaN barrier layer (7), and a GaN cap layer (8) which are arranged successively from bottom to top. Among them, the high-resistance buffer layer (4) successively includes a Fe-doped GaN buffer layer, a hexagonal BN buffer layer, and a C-doped GaN buffer layer from bottom to top; on the upper surface of the GaN cap layer (8), a source electrode (9), a drain electrode (10), and a gate electrode (11) are arranged at intervals. The source electrode (9) and the drain electrode (10) respectively form ohmic contacts with the AlGaN barrier layer (7); the gate electrode (11) forms a Schottky contact with the AlGaN barrier layer (7).

2. The GaN HEMT device with a high-resistance buffer layer according to claim 1, wherein the substrate (1) is Si with a (111) plane, SiC with a (001) plane, or sapphire with a (001) plane.

3. The GaN HEMT device with a high-resistance buffer layer according to claim 1, wherein the stress regulation layer (3) is an AlGaN buffer layer with a gradually changing Al component or an AlN / GaN superlattice buffer layer. The gradually changing range of the Al component of the AlGaN buffer layer is 0-100%.

4. The GaN HEMT device with a high-resistance buffer layer according to claim 1, wherein The thickness of the high-resistance buffer layer (4) is 300 - 2500 nm. Among them, the thickness of the Fe-doped GaN buffer layer is 100 - 1000 nm, and the doping concentration of Fe is 1×10 18 -1×10 19 cm -3 ; the thickness of the hexagonal BN buffer layer is 100 - 500 nm; the thickness of the C-doped GaN buffer layer is 100 - 1000 nm, and the doping concentration of C is 1×10 17 -1×10 18 cm -3 .

5. The GaN HEMT device with a high-resistance buffer layer according to claim 1, wherein The Fe concentration of the GaN channel layer (5) is less than or equal to 1×10 16 cm -3 .

6. A preparation method of a GaN HEMT device with a high-resistance buffer layer, which is used to prepare the GaN HEMT device with a high-resistance buffer layer described in any one of claims 1 to 5. The preparation method includes: S1: Grow an AlN nucleation layer on the upper surface of the substrate; S2: Grow a stress regulation layer on the upper surface of the AlN nucleation layer; S3: Grow a high-resistance buffer layer on the upper surface of the stress regulation layer. The high-resistance buffer layer successively includes a Fe-doped GaN buffer layer, a hexagonal BN buffer layer, and a C-doped GaN buffer layer from bottom to top; S4: Grow a GaN channel layer on the upper surface of the high-resistance buffer layer; S5: Grow an AlN insertion layer on the upper surface of the GaN channel layer; S6: Grow an AlGaN barrier layer on the upper surface of the AlN insertion layer; S7: Grow a GaN cap layer on the upper surface of the AlGaN barrier layer; S8: Prepare a source electrode, a drain electrode, and a gate electrode at intervals on the upper surface of the GaN cap layer.

7. The manufacturing method of the GaN HEMT device with a high-resistance buffer layer according to claim 6, characterized in that, The S1 includes: Grow an AlN nucleation layer on the upper surface of the substrate. The substrate is Si with a (111) plane, SiC with a (001) plane, or sapphire with a (001) plane, and the size is 2-8 inches; the growth temperature of the nucleation layer is 1000-1100 °C, the growth pressure is 40-100 torr, and the growth thickness is 200-300 nm.

8. The manufacturing method of the GaN HEMT device with a high-resistance buffer layer according to claim 6, characterized in that, The S3 includes: Grow a Fe-doped GaN buffer layer with a thickness of 100-1000 nm on the upper surface of the stress regulation layer. The Fe source is Cp2Fe, the Cp2Fe flow rate is 100-600 sccm, the growth temperature is 1000-1100 °C, and the growth pressure is 40-100 torr; Grow a hexagonal BN buffer layer with a thickness of 100-500 nm on the upper surface of the Fe-doped GaN buffer layer. The boron source is BCl3, the growth temperature is 1100-1500 °C, and the growth pressure is 1-20 torr; A C-doped GaN buffer layer with a thickness of 100 - 1000 nm is grown on the upper surface of the hexagonal BN buffer layer by in-situ doping, with a growth temperature of 500 - 1000 °C and a growth pressure of 40 - 100 torr.

9. The manufacturing method of the GaN HEMT device with a high-resistance buffer layer according to claim 6, characterized in that, The S8 includes: A source electrode, a drain electrode, and a gate electrode are respectively fabricated on the GaN cap layer, wherein the source electrode and the drain electrode respectively form ohmic contacts with the AlGaN barrier layer; the gate electrode forms a Schottky contact with the AlGaN barrier layer.

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