Gallium nitride power electronic device preparation method and gallium nitride power electronic device

Abstract

The invention provides a gallium nitride power electronic device preparation method and a gallium nitride power electronic device, and relates to the technical field of semiconductors. The method comprises the following steps: bonding a reinforcing plate on the front surface of a prepared device; performing overall thinning processing on the substrate of the device from the back surface of the device so as to thin the substrate to a preset thickness range; processing heat dissipation holes in the back surface of the substrate; heat conduction materials are arranged on the back face of the substrate and in the heat dissipation holes, so that a heat conduction layer is formed on the back face of the substrate; and the bonding of the reinforcing plate is removed. According to the preparation method of the gallium nitride power electronic device, the substrate can be thinned, the problem that the substrate is broken can be avoided, and the heat dissipation capability of the device is enhanced by arranging the heat conduction layer, so that the performance and reliability of the device are improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for preparing a gallium nitride power electronic device and a gallium nitride power electronic device. Background Art

[0002] Gallium nitride power electronic devices have the advantages of wide band gap, high breakdown field strength, high electron mobility, and high power density, and have great potential in high-temperature, high-frequency, and high-power power electronic applications.

[0003] Gallium nitride power electronic devices have been used in low-power fields such as mobile phone fast charging, and are currently being studied in higher-power application fields such as data centers and automotive electronics. However, as the power density increases, heat dissipation issues seriously restrict the performance and reliability of gallium nitride power devices. In order to improve the heat dissipation capacity of gallium nitride HEMT power devices, the current mainstream method is to thin the substrate and enhance the heat conduction capacity from the device to the bracket. However, if the substrate is thinned too much, it is easy to break in subsequent processing. Summary of the invention

[0004] The purpose of the present invention includes providing a method for preparing a gallium nitride power electronic device and a gallium nitride power electronic device, which can improve the heat dissipation performance of the gallium nitride power device and can improve the problem of fragmentation.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] In a first aspect, the present invention provides a method for preparing a gallium nitride power electronic device, the method comprising:

[0007] Bonding a reinforcing plate to the front side of the fabricated device;

[0008] Performing a global thinning process on the substrate of the device from the back side of the device, so as to thin the substrate to a preset thickness range;

[0009] Processing heat dissipation holes on the back side of the substrate;

[0010] Disposing a heat-conducting material on the back side of the substrate and in the heat-dissipating hole to form a heat-conducting layer on the back side of the substrate;

[0011] The reinforcement plate is debonded.

[0012] In an optional embodiment, the reinforcing plate is made of a transparent material so that the photolithography equipment can obtain the marking on the front side of the device through the reinforcing plate.

[0013] In an optional embodiment, the reinforcing plate is a glass or sapphire sheet.

[0014] In an optional embodiment, the reinforcing plate is bonded to the front side of the device by the bonding adhesive.

[0015] In an optional embodiment, the step of globally thinning the substrate of the device from the back side of the device to reduce the thickness of the substrate to a preset range includes:

[0016] The back side of the substrate is thinned globally by using a grinding device, so that the thickness of the substrate is reduced to between 40 μm and 300 μm.

[0017] In an optional implementation, the heat dissipation holes are honeycomb-shaped, and the diameter of the heat dissipation holes ranges from 10um to 200um.

[0018] In an optional embodiment, the back side of the substrate has a first region corresponding to the active region of the device and a second region corresponding to the inactive region of the device;

[0019] The first area and the second area are both provided with the heat dissipation holes, and the heat dissipation holes in the first area account for an area value ranging from 40% to 70%, and the heat dissipation holes in the second area account for an area value ranging from 15% to 40%.

[0020] In an optional embodiment, the heat conductive layer is copper;

[0021] The step of providing a heat-conducting material on the back side of the substrate and in the heat-dissipating hole to form a heat-conducting layer on the back side of the substrate comprises:

[0022] Depositing a metal seed layer on the back side of the substrate by magnetron sputtering;

[0023] The device is then placed in an electroplating device to electroplatingly deposit copper with a thickness of 5 μm to 100 μm.

[0024] In an optional embodiment, the device comprises:

[0025] substrate;

[0026] A GaN buffer layer is disposed on the surface of the substrate;

[0027] A GaN channel layer is disposed on a surface of the GaN buffer layer away from the substrate;

[0028] An AlGaN barrier layer is disposed on a surface of the GaN channel layer away from the GaN buffer layer;

[0029] An electrode layer, arranged on a side of the AlGaN barrier layer away from the substrate, the electrode layer being provided with a gate, a source and a drain;

[0030] The surface of the substrate away from the buffer layer is the back side of the device, and the surface of the electrode layer away from the barrier layer is the front side of the device.

[0031] In a second aspect, the present invention provides a gallium nitride power electronic device, wherein the gallium nitride power electronic device is prepared by the gallium nitride power electronic device preparation method described in any one of the aforementioned embodiments.

[0032] The beneficial effects of the gallium nitride power electronic device manufacturing method and the gallium nitride power electronic device provided by the embodiments of the present invention include:

[0033] The preparation method provided by the present application can improve the mechanical strength of the device by bonding a reinforcing plate on the front of the prepared device, and can protect the front of the prepared device, and then thin the substrate on the back of the prepared device, so that the problem of broken pieces in the processes of thinning, preparing heat dissipation holes and forming a thermal conductive layer can be improved due to the support of the reinforcing plate. Secondly, the honeycomb heat dissipation holes on the substrate surface are conducive to the uniform release of epitaxial layer stress, alleviate the stress accumulation and warping of the device after thinning, and also improve the problem of broken pieces in the substrate after thinning. The present application also processes heat dissipation holes on the back of the substrate, and sets a thermal conductive material on the back of the substrate and in the heat dissipation holes to form a thermal conductive layer on the back of the substrate, so that the thermal conductive layer has a larger thermal conductivity relative to the substrate, and can conduct heat away well. In addition, the setting of the heat dissipation holes can further reduce the thickness of some areas, further improving the thermal conductivity effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 A schematic diagram of the structure of a device prepared by the process for preparing a gallium nitride power electronic device provided in this embodiment;

[0036] Figure 2 A schematic diagram of the structure of the gallium nitride power electronic device manufacturing process provided in this embodiment after the reinforcing plate is bonded to the front side of the device;

[0037] Figure 3 A schematic diagram of the structure of the gallium nitride power electronic device manufacturing process provided in this embodiment after the back side of the device is thinned;

[0038] Figure 4A schematic diagram of the structure of the gallium nitride power electronic device manufacturing process provided in this embodiment after the back side of the substrate is thinned and heat dissipation holes are processed;

[0039] Figure 5 A schematic diagram of the layout of heat dissipation holes provided on the back side of the substrate in the gallium nitride power electronic device manufacturing process provided in this embodiment;

[0040] Figure 6 A schematic diagram of the structure of the gallium nitride power electronic device manufacturing process provided in this embodiment after a heat-conducting layer is prepared on the back side of the substrate;

[0041] Figure 7 A schematic structural diagram of a gallium nitride power electronic device after the reinforcing plate is released from the bonding process of the gallium nitride power electronic device provided in this embodiment.

[0042] Icons: 100 - GaN power electronic device; 110 - device; 111 - substrate; 112 - GaN buffer layer; 113 - GaN channel layer; 114 - AlGaN barrier layer; 115 - electrode layer; 116 - P-GaN layer; 117 - SiO2 dielectric layer; 118 - gate; 119 - source; 121 - drain; 122 - ion implanted channel isolation layer; 151 - reinforcement plate; 152 - heat dissipation hole; 153 - thermal conductive layer; 154 - bonding glue; 155 - first region; 156 - second region. DETAILED DESCRIPTION

[0043] The heat dissipation problem restricts the performance of GaN power devices. In order to improve the heat dissipation capacity of GaN power devices, the current mainstream method is to thin the substrate and enhance the heat conduction capacity from the device to the bracket. However, if the substrate is thinned too much, it is easy to break in the subsequent processing technology.

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0047] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0048] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0049] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0050] Please refer to Figures 1 to 7 The present application provides a method for preparing a gallium nitride power electronic device, which is used to prepare a gallium nitride power electronic device 100. The gallium nitride power electronic device 100 is a gallium nitride power device 110, which has better heat dissipation performance and a thinner substrate 111.

[0051] In this embodiment, the method for preparing a gallium nitride power electronic device includes:

[0052] Please refer to Figure 1 and Figure 2 , S1, bonding a reinforcing plate 151 on the front side of the prepared device 110;

[0053] Please refer to Figure 2 and Figure 3 , S2, performing a global thinning process on the substrate 111 of the device 110 from the back side of the device 110, so that the substrate 111 is thinned to a preset thickness range;

[0054] Please parameter Figure 3 , Figure 4 and Figure 5 , S3, processing heat dissipation holes 152 on the back side of the substrate 111;

[0055] Please refer to Figure 4 and Figure 6 , S4, disposing a heat-conducting material on the back side of the substrate 111 and in the heat dissipation hole 152 to form a heat-conducting layer 153 on the back side of the substrate 111;

[0056] Please refer to Figure 6 and Figure 7, S5, release the bonding of the reinforcing plate 151.

[0057] Please refer to Figures 1 to 7 The preparation method provided in this embodiment can improve the mechanical strength of the device 110 by bonding the reinforcing plate 151 on the front of the prepared device 110, and can protect the front of the prepared device 110, and then thin the substrate 111 on the back of the prepared device 110. In this way, due to the support of the reinforcing plate 151, the problem of broken pieces in the processes of thinning, preparing the heat dissipation holes 152 and forming the heat conductive layer 153 can be improved. Secondly, the honeycomb heat dissipation holes on the substrate surface are conducive to the uniform release of the stress of the epitaxial layer, relieve the stress accumulation and warping of the device after thinning, and also improve the problem of broken pieces of the substrate 111 after thinning. The present application also processes the heat dissipation holes 152 on the back of the substrate 111, and sets a heat conductive material on the back of the substrate 111 and in the heat dissipation holes 152 to form a heat conductive layer 153 on the back of the substrate 111, so that the heat conductive layer 153 has a larger thermal conductivity than the substrate 111, and can conduct heat away well. In addition, the provision of the heat dissipation holes 152 can further reduce the thickness of some areas, further improving the heat conduction effect.

[0058] It should be noted that the substrate 111 can be one of Si, SiC, sapphire, and gallium oxide. Optionally, the material of the substrate 111 is sapphire. The 4-inch, 6-inch, 8-inch and larger-sized sapphire substrates 111 are low in price and can be used to prepare large-sized wafers. In addition, the sapphire substrate 111 has good insulation and mechanical properties, and the growth of the GaN epitaxial layer is easier.

[0059] For large-sized wafers, such as 4-inch, 6-inch, 8-inch and above wafers, when the thickness of the wafer is set to 40μm-300μm, when the epitaxial layer is grown on the surface of the substrate 111, due to the different lattice constants of GaN and the substrate material, the stress of the epitaxial layer growth process increases, and the thin substrate causes the grown wafer to be warped or even cracked, which is not suitable for mass production. In order to facilitate mass production, the general thickness of the substrate 111 used in the existing device 110 is about 450-1000μm, and even the larger the substrate diameter, the thicker the substrate thickness, and the specific thickness is related to the size of the wafer. The increase in the thickness of the substrate 111 will lead to a decrease in the heat dissipation capacity of the device 110, and a decrease in the device performance and reliability.

[0060] The fabricated device 110 of this embodiment refers to a fabricated existing device 110, wherein the thickness of the substrate 111 is relatively thick, and the epitaxial layer is grown on the surface of the substrate 111, and the device 110 is annealed. In this embodiment, the substrate 111 thinning process of the device 110 is placed at a later stage, so that when the epitaxial layer is grown on the surface of the substrate 111, the thickness of the substrate 111 is still relatively thick, thereby improving the problem of fragmentation.

[0061] Please refer to Figure 1 In this embodiment, the fabricated device 110 includes a substrate 111, a GaN buffer layer 112, a GaN channel layer 113, an AlGaN barrier layer 114 and an electrode layer 115. The thickness of the substrate 111 is thicker than the thickness of the substrate 111 of the device 110 after thinning. It is generally about 450-1000 μm, which is determined according to the size of the device 110. The GaN buffer layer 112 is disposed on the surface of the substrate 111. The GaN channel layer 113 is disposed on the surface of the GaN buffer layer 112 away from the substrate 111. The AlGaN barrier layer 114 is disposed on the surface of the GaN channel layer 113 away from the GaN buffer layer 112. The electrode layer 115 is disposed on the side of the AlGaN barrier layer 114 away from the substrate 111, and the electrode layer 115 is provided with a gate 118, a source 119 and a drain 121. Ion-implanted channel isolation layers 122 are provided on both sides of the GaN channel layer 113 and the AlGaN barrier layer 114. A P-GaN layer 116 is provided in the region corresponding to the gate 118 on the upper surface of the AlGaN barrier layer 114. A SiO2 dielectric layer 117 is also provided in the corresponding region on the front side. The surface of the substrate 111 away from the buffer layer is the back side of the device 110, and the surface of the electrode layer 115 away from the barrier layer is the front side of the device 110.

[0062] In this embodiment, the reinforcing plate 151 is made of a transparent material, so that the photolithography equipment can obtain the mark on the front side of the device 110 through the reinforcing plate 151 .

[0063] When processing the heat dissipation hole 152 on the back side of the substrate 111, the position needs to be determined, and the position is determined based on the mark on the front side of the device 110. In this embodiment, the reinforcing plate 151 is set to be a transparent material, so that when the heat dissipation hole 152 is processed by photolithography, the mask can be positioned through the mark on the front side of the device 110, thereby realizing the positioning of the heat dissipation hole 152.

[0064] In this embodiment, the reinforcing plate 151 is a glass or sapphire sheet. Since the glass or sapphire sheet has both transparent properties and strong mechanical support performance, it is low in cost and can be reused.

[0065] Please refer to Figures 1 to 7 In this embodiment, the reinforcing plate 151 is bonded to the front side of the device 110 by means of a bonding adhesive 154. Since the reinforcing plate 151 needs to be released from the bonding in the subsequent process, i.e., removed from the front side of the device 110, in this embodiment, the reinforcing plate 151 is bonded by means of the bonding adhesive 154, which facilitates bonding and releasing, and the bonding adhesive 154 will not affect the electrode layer 115 on the front side of the device 110.

[0066] In this embodiment, step S2 includes the following sub-steps:

[0067] S21 . Use a grinding device to globally thin the back side of the substrate 111 , so that the thickness of the substrate 111 is reduced to between 40 μm and 300 μm.

[0068] It should be noted that when the grinding equipment is grinding, one side of the reinforcing plate 151 bonded to the front side of the device 110 is fixed to the grinding equipment, so that the electrode layer 115 on the front side of the device 110 is isolated by the reinforcing plate 151, which can avoid damage to the electrode layer 115 during grinding. The reinforcing plate 151 can protect the electrode layer 115.

[0069] The thickness of the substrate 111 after grinding can be determined according to the size of the device 110. For example, if the size of the device 110 is small, the thickness of the substrate 111 after grinding can be between 40 μm and 100 μm, such as 40 μm, 75 μm, 100 μm, etc. If the size of the device 110 is large, the thickness of the substrate 111 can be between 100 μm and 300 μm, such as 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, etc.

[0070] In this embodiment, the heat dissipation holes 152 are honeycomb-shaped, and the diameter of the heat dissipation holes 152 ranges from 10um to 200um. The honeycomb structure is a typical porous material, which has higher porosity, higher specific stiffness, specific strength, specific energy absorption, and excellent fracture toughness, impact resistance, and heat dissipation, and can avoid the strength of the perforated substrate 111.

[0071] In this embodiment, the heat dissipation holes 152 are round holes, which are easy to process. Of course, in other embodiments of the present application, the heat dissipation holes 152 can also be set as polygonal holes, for example, hexagonal holes. These heat dissipation holes 152 can be distributed in a hexagonal close-packed geometric structure.

[0072] Please refer to Figures 1 to 7 In this embodiment, the depth of the heat dissipation hole 152 is less than the thickness of the substrate 111 after thinning, and the depth of the heat dissipation hole 152 is in the range of 20μm-250μm. The depth of the heat dissipation hole 152 can be determined according to parameters such as the heat generation and the size of the device 110. For example, 20μm, 50μm, 100μm, 150Um, 200μm, 250μm, etc.

[0073] In this embodiment, the process of processing the heat dissipation hole 152 on the back side of the substrate 111 is:

[0074] The photolithography mask is fixed to the photolithography machine, and the device 110 is also fixed to the photolithography machine, with the back of the device 110 facing upward and the side bonded with the reinforcing plate 151 facing downward. Photoresist is applied to the back of the substrate 111, and the marking points on the front of the device 110 are obtained by the CCD camera to align the photolithography mask with the device 110, and the photolithography is completed to obtain the area to be punched. A hole with a depth of 20μm-250μm is etched on the substrate 111 by wet etching, dry etching or laser etching process.

[0075] Please refer to Figures 1 to 7 In this embodiment, the back side of the substrate 111 has a first region 155 corresponding to the active region of the device 110 and a second region 156 corresponding to the inactive region of the device 110. The first region 155 and the second region 156 are both provided with heat dissipation holes 152, and the area ratio of the heat dissipation holes 152 in the first region 155 is in the range of 40%-70%, and the area ratio of the heat dissipation holes 152 in the second region 156 is in the range of 15%-40%.

[0076] Since the heat of the device 110 is generally concentrated in the active area, while the heat of the inactive area is generally less, this embodiment makes the heat dissipation holes 152 of the first area 155 corresponding to the active area on the back of the substrate 111 more dense, while the heat dissipation holes 152 of the second area 156 are more sparse, so that the substrate 111 can be ensured to have a certain strength and the heat dissipation capacity can be improved.

[0077] For example, in some embodiments, the area ratio of the heat dissipation holes 152 in the first region 155 is 70%, and the area ratio of the heat dissipation holes 152 in the second region 156 is 30%. Of course, in other embodiments of the present application, the ratio of the heat dissipation holes 152 in the first region 155 to the heat dissipation holes 152 in the second region 156 can be set according to actual heat dissipation requirements, as long as the heat dissipation holes 152 in the first region 155 are arranged densely relative to the heat dissipation holes 152 in the second region 156.

[0078] In this embodiment, the heat conducting layer 153 is copper. Step S4 includes the following sub-steps:

[0079] S41, depositing a metal seed layer on the back side of the substrate 111 by magnetron sputtering;

[0080] S42, placing the device 110 in an electroplating device to electroplatingly deposit copper with a thickness of 5 μm-100 μm.

[0081] The reason why copper is used for the heat conducting layer 153 is that copper has a high thermal conductivity, which can better conduct heat. The 5μm-100μm thick copper deposited here is the thickness of the copper to the back of the substrate 111, excluding the thickness of the copper in the heat dissipation hole 152. The thickness of the copper can be determined according to the heat dissipation amount.

[0082] It should be noted that, generally after copper is deposited, due to the presence of the heat dissipation holes 152, the back surface will be machined to keep it flat.

[0083] Please refer to Figures 1 to 7 In this embodiment, step S5 includes the following sub-steps:

[0084] The device 110 processed through steps S1 to S4 and their sub-steps is placed in an organic solvent to separate the device 110 and the reinforcing plate 151 .

[0085] In summary, the gallium nitride power electronic device manufacturing method and gallium nitride power electronic device 100 provided by the embodiment of the present invention can improve the mechanical strength of the device 110 by bonding the reinforcing plate 151 on the front side of the manufactured device 110, and can protect the front side of the manufactured device 110, and then thin the substrate 111 on the back side of the manufactured device 110, so that the problem of broken pieces in the processes of thinning, preparing the heat dissipation holes 152 and forming the heat conductive layer 153 can be improved due to the support of the reinforcing plate 151. Secondly, the step of thinning the substrate 111 is placed at a later stage, and the step of preparing the device 110 is performed before the substrate 111 is thinned, so as to reduce the process steps after the substrate 111 is thinned, and also improve the problem of broken pieces in the substrate 111 after thinning. The present application also processes heat dissipation holes 152 on the back of the substrate 111, and arranges heat-conducting materials on the back of the substrate 111 and in the heat dissipation holes 152 to form a heat-conducting layer 153 on the back of the substrate 111. In this way, the heat-conducting layer 153 has a greater thermal conductivity than the substrate 111, and can conduct heat away well. In addition, the arrangement of the heat dissipation holes 152 can further reduce the thickness of some areas, further improving the heat conduction effect.

[0086] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a gallium nitride power electronic device, characterized in that: The method comprises: Bonding a reinforcing plate (151) to the front side of the manufactured device (110); Performing a global thinning process on the substrate (111) of the device (110) from the back side of the device (110), so as to thin the substrate (111) to a preset thickness range; Processing heat dissipation holes (152) on the back side of the substrate (111); Disposing a heat-conducting material on the back side of the substrate (111) and in the heat-dissipating hole (152) to form a heat-conducting layer (153) on the back side of the substrate (111); The reinforcing plate (151) is debonded.

2. The method for preparing a gallium nitride power electronic device according to claim 1, characterized in that: The reinforcing plate (151) is made of a transparent material, so that a photolithography device can obtain the mark on the front side of the device (110) through the reinforcing plate (151).

3. The method for preparing a gallium nitride power electronic device according to claim 2, characterized in that: The reinforcing plate (151) is a glass or sapphire sheet.

4. The method for preparing a gallium nitride power electronic device according to any one of claims 1 to 3, characterized in that: The reinforcing plate (151) is bonded to the front side of the device (110) via bonding glue (154).

5. The method for preparing a gallium nitride power electronic device according to any one of claims 1 to 3, characterized in that: The step of globally thinning the substrate (111) of the device (110) from the back side of the device (110) so as to thin the substrate (111) to a preset thickness range comprises: The back side of the substrate (111) is thinned globally by using a grinding device, so that the thickness of the substrate (111) is reduced to between 40 μm and 300 μm.

6. The method for preparing a gallium nitride power electronic device according to any one of claims 1 to 3, characterized in that: The heat dissipation holes (152) are honeycomb-shaped, and the diameter of the heat dissipation holes (152) ranges from 10um to 200um.

7. The method for preparing a gallium nitride power electronic device according to any one of claims 1 to 3, characterized in that: The back side of the substrate (111) has a first region (155) corresponding to the active region of the device (110) and a second region (156) corresponding to the inactive region of the device (110); The first region (155) and the second region (156) are both provided with the heat dissipation holes (152), and the area ratio of the heat dissipation holes (152) in the first region (155) is in the range of 40%-70%, and the area ratio of the heat dissipation holes (152) in the second region (156) is in the range of 15%-40%.

8. The method for preparing a gallium nitride power electronic device according to any one of claims 1 to 3, characterized in that: The heat conducting layer (153) is copper; The step of arranging a heat-conducting material on the back side of the substrate (111) and in the heat dissipation hole (152) to form a heat-conducting layer (153) on the back side of the substrate (111) comprises: Depositing a metal seed layer on the back side of the substrate (111) by magnetron sputtering; The device (110) is then placed in an electroplating device to electroplatingly deposit copper with a thickness of 5 μm to 100 μm.

9. The method for preparing a gallium nitride power electronic device according to any one of claims 1 to 3, characterized in that: The device (110) comprises: A substrate (111); A GaN buffer layer (112) is disposed on the surface of the substrate (111); A GaN channel layer (113) is arranged on a surface of the GaN buffer layer (112) away from the substrate (111); An AlGaN barrier layer (114) is arranged on a surface of the GaN channel layer (113) away from the GaN buffer layer (112); An electrode layer (115) is arranged on a side of the AlGaN barrier layer (114) away from the substrate (111), and the electrode layer (115) is provided with a gate (118), a source (119) and a drain (121); The surface of the substrate (111) away from the buffer layer is the back side of the device (110), and the surface of the electrode layer (115) away from the AlGaN barrier layer (114) is the front side of the device (110).

10. A gallium nitride power electronic device, characterized in that: The gallium nitride power electronic device (100) is prepared by the gallium nitride power electronic device preparation method according to any one of claims 1 to 9.

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