A GaN HEMT device

Abstract

The application discloses a GaN HEMT device, which comprises a substrate, a buffer layer, a GaN channel layer and a barrier layer arranged in a stack along a first direction, and a source electrode, a gate structure and a drain electrode are arranged on the surface of the barrier layer away from the GaN channel layer and are spaced from each other; further comprising a reverse freewheeling diode arranged on the surface of the barrier layer away from the GaN channel layer and between the gate structure and the drain electrode, comprising a metal anode and a plurality of first P-GaN structures, each first P-GaN structure is at least partially located on the side of the metal anode close to the drain electrode, the plurality of first P-GaN structures are in contact with the metal anode and are arranged in a comb shape. The first P-GaN structure is arranged on the surface of the barrier layer away from the GaN channel layer, the plurality of first P-GaN structures are arranged in parallel and spaced apart in a second direction, the metal anode forms a Schottky contact with the barrier layer and an ohmic contact with the first P-GaN structure. Through the above arrangement, the problem of large reverse leakage current and poor voltage resistance of the integrated Schottky diode in the prior art is solved.

Description

Technical Field

[0001] This application relates to the semiconductor field, and in particular to a GaN HEMT device. Background Technology

[0002] Compared to first-generation semiconductor material Si, third-generation wide-bandgap semiconductor material GaN possesses superior material physics properties. Its physical parameters, such as bandgap width, electron mobility, electron saturation velocity, critical breakdown electric field, thermal conductivity, and high / low frequency Baliga figure of merit, are all significantly higher than those of Si. Currently, P-GaN gate power HEMTs are commercially available and exhibit excellent performance.

[0003] In many power switching circuits, such as inverters and DC-DC converters, power transistors need to be connected in anti-parallel with freewheeling diodes to achieve reverse conduction. However, since P-GaN gate power HEMTs lack a body diode, the reverse conduction voltage of the HEMT is coupled to the device threshold voltage, resulting in a high reverse conduction voltage, which leads to higher energy losses and lower efficiency. External parallel diodes not only increase cost but also introduce additional parasitic inductance and capacitance. One solution to this problem is to integrate a planar Schottky diode onto the HEMT, but planar Schottky diodes suffer from high reverse leakage current and poor breakdown voltage. Summary of the Invention

[0004] This application provides a GaN HEMT device to address the problems of large reverse leakage current and poor withstand voltage in existing integrated Schottky diodes.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide a GaN HEMT device, including a substrate, a buffer layer, a GaN channel layer and a barrier layer stacked sequentially along a first direction; the surface of the barrier layer away from the GaN channel layer is provided with a source, a gate structure and a drain that are spaced apart from each other, and the gate structure is disposed between the source and the drain.

[0006] The device also includes a reverse freewheeling diode integrated on the surface of the barrier layer away from the GaN channel layer. The reverse freewheeling diode is disposed between the gate structure and the drain, and includes a metal anode and a plurality of first P-GaN structures. The metal anode is spaced apart from the gate structure, and each first P-GaN structure is at least partially located on the side of the metal anode near the drain. The plurality of first P-GaN structures are contacted with the metal anode and arranged in a comb-like pattern. The first P-GaN structures are disposed on the surface of the barrier layer away from the GaN channel layer. The metal anode extends along a second direction, and the plurality of first P-GaN structures are parallel to each other and spaced apart in the second direction. Each first P-GaN structure extends along a third direction. The metal anode forms a Schottky contact with the barrier layer and an ohmic contact with the first P-GaN structures.

[0007] The beneficial effects of this application are as follows: Unlike existing technologies, this application discloses a GaN HEMT device, including a substrate, a buffer layer, a GaN channel layer, and a barrier layer stacked along a first direction. The surface of the barrier layer away from the GaN channel layer has mutually spaced source, gate, and drain structures. It also includes a reverse freewheeling diode integrated on the surface of the barrier layer away from the GaN channel layer and located between the gate structure and the drain. This diode includes a metal anode and multiple first P-GaN structures, each first P-GaN structure being at least partially located on the side of the metal anode near the drain. The multiple first P-GaN structures are in contact with the metal anode and arranged in a comb-like pattern. The first P-GaN structures are located on the surface of the barrier layer away from the GaN channel layer. The metal anode extends along a second direction, and the multiple first P-GaN structures are parallel and spaced apart along the second direction. The metal anode forms a Schottky contact with the barrier layer and an ohmic contact with the first P-GaN structures. This configuration solves the problems of large reverse leakage current and poor withstand voltage in existing integrated Schottky diodes. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0009] Figure 1 This is a schematic diagram of the structure of the first embodiment of the GaN HEMT device provided in this application;

[0010] Figure 2 yes Figure 1A top view of the provided GaN HEMT device;

[0011] Figure 3 yes Figure 1 A schematic cross-sectional view of the first section of the provided GaN HEMT device;

[0012] Figure 4 yes Figure 1 A schematic cross-sectional view of the second section of the provided GaN HEMT device;

[0013] Figure 5 This is a schematic diagram of the structure of the second embodiment of the GaN HEMT device provided in this application;

[0014] Figure 6 yes Figure 5 A schematic cross-sectional view of the first section of the provided GaN HEMT device;

[0015] Figure 7 This is a schematic diagram of the structure of the third embodiment of the GaN HEMT device provided in this application;

[0016] Figure 8 yes Figure 7 A schematic cross-sectional view of the first section of the provided GaN HEMT device;

[0017] Figure 9 This is a schematic diagram of the structure of the fourth embodiment of the GaN HEMT device provided in this application;

[0018] Figure 10 yes Figure 9 A schematic cross-sectional view of the first section of the provided GaN HEMT device;

[0019] Figure 11 This is a schematic flowchart of the fabrication method of the GaN HEMT device provided in this application. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] The terms "first," "second," and "third" used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] See Figures 1 to 10 , Figure 1 This is a schematic diagram of the structure of the first embodiment of the GaN HEMT device provided in this application. Figure 2 yes Figure 1 The provided top view diagram of the GaN HEMT device. Figure 3 yes Figure 1 A schematic cross-sectional view of the first section of the provided GaN HEMT device. Figure 4 yes Figure 1 A schematic cross-sectional view of the second section of the provided GaN HEMT device. Figure 5 This is a schematic diagram of the structure of the second embodiment of the GaN HEMT device provided in this application. Figure 6 yes Figure 5 A schematic cross-sectional view of the first section of the provided GaN HEMT device. Figure 7 This is a schematic diagram of the structure of the third embodiment of the GaN HEMT device provided in this application. Figure 8 yes Figure 7 A schematic cross-sectional view of the first section of the provided GaN HEMT device. Figure 9 This is a schematic diagram of the structure of the fourth embodiment of the GaN HEMT device provided in this application. Figure 10 yes Figure 9 A schematic cross-sectional view of the first section of the provided GaN HEMT device.

[0024] See Figure 1 This application provides a GaN HEMT device 100, which includes a substrate 1, a buffer layer 2, a GaN channel layer 3, and a barrier layer 4 sequentially stacked along a first direction A1. A source 5, a gate structure 6, and a drain 7 are disposed on the surface of the barrier layer 4 away from the GaN channel layer 3, spaced apart from each other. The gate structure 6 is disposed between the source 5 and the drain 7. The GaN HEMT device 100 also includes a reverse freewheeling diode 8, which is integrated on the surface of the barrier layer 4 away from the GaN channel layer 3 and disposed between the gate structure 6 and the drain 7. Specifically, the reverse freewheeling diode 8 includes a metal anode 81 and a plurality of first P-GaN structures 82. The metal anode 81 is spaced apart from the gate structure 6, and each first P-GaN structure 82 is at least partially located on the side of the metal anode 81 near the drain 7. The plurality of first P-GaN structures 82 are in contact with the metal anode 81 and arranged in a comb-like pattern. A first P-GaN structure 82 is disposed on the surface of the barrier layer 4 away from the GaN channel layer 3. A metal anode 81 extends along the second direction A2. Multiple first P-GaN structures 82 are arranged parallel to each other and spaced apart along the second direction A2. Each first P-GaN structure 82 extends along the third direction A3. The metal anode 81 forms a Schottky contact with the barrier layer 4 and an ohmic contact with the first P-GaN structure 82. The first direction A1 is the thickness direction of the GaN HEMT device 100, the third direction A3 is the direction extending from the source 5 to the drain 7 (i.e., the length direction), and the second direction A2 is the direction perpendicular to both the third direction A3 and the first direction A1 (i.e., the width direction).

[0025] With the above configuration, multiple first P-GaN structures 82 are arranged in a comb-like pattern along the second direction A2, that is, multiple first P-GaN structures 82 are parallel to each other and spaced apart. The multiple first P-GaN structures 82 do not completely cover the barrier layer 4. Therefore, when the GaN HEMT device 100 is forward-biased, the drain 7 is positively charged, the integrated reverse freewheeling diode 8 is in the off state, and 2DEG (two-dimensional electron gas) still exists in the GaN channel layer 3 below the barrier layer 4 which is not covered by the multiple first P-GaN structures 82. The GaN HEMT device 100 will conduct normally. When the GaN HEMT device 100 is off-voltage, the integrated reverse freewheeling diode 8 withstands voltage. The holes in the multiple first P-GaN structures 82 arranged in a comb-like pattern deplete each other with the 2DEG in the GaN channel layer 3 below the multiple first P-GaN structures 82, forming a superjunction structure. This can improve the local electric field concentration effect, modulate the electric field in the device drift region, and increase the breakdown voltage of the GaN HEMT device 100. At the same time, it greatly weakens the Schottky barrier reduction effect and reduces the leakage current of the GaN HEMT device 100. When the GaN HEMT device 100 is reverse freewheeling, one end of the source 5 of the GaN HEMT device 100 is positively charged, and the Schottky junction formed by the metal anode 81 and the barrier layer 4 is conducting. The current reaches the drain 7 through the 2DEG channel below the barrier layer 4, resulting in lower losses and effectively solving the problems of large reverse leakage current and poor withstand voltage of integrated Schottky diodes in the prior art.

[0026] Specifically, the gate structure 6 includes a second P-GaN structure 61 and a gate 62 stacked together. The second P-GaN structure 61 is disposed on the surface of the barrier layer 4 away from the GaN channel layer 3, and the gate 62 is disposed on the surface of the second P-GaN structure 61 away from the barrier layer 4. The source 5 forms an ohmic contact with the barrier layer 4, and the drain 7 forms an ohmic contact with the barrier layer 4. The gate 62 and the second P-GaN structure 61 can form an ohmic contact or a Schottky contact. The metal anode 81 is electrically connected to the source 5. The material of the barrier layer 4 includes AlGaN, and the material of the buffer layer 2 can include GaN.

[0027] See Figures 1 to 4Along the second direction A2, the metal anode 81 is in contact with both the surface of the first P-GaN structure 82 away from the barrier layer 4 and the surface of the barrier layer 4 away from the GaN channel layer 3. A portion of the metal anode 81 covers a portion of the first P-GaN structure 82, and another portion covers a portion of the barrier layer 4. The GaN HEMT device 100 includes a first cross-section B1 and a second cross-section B2 spaced apart and parallel to each other along the second direction A2. The first cross-section B1 is located in the region where the first P-GaN structure 82 is located, and the second cross-section B2 is located in the region spaced between the multiple first P-GaN structures 82. On the first cross-section B1, the metal anode 81 covers a portion of the surface of the first P-GaN structure 82 away from the barrier layer 4. On the second cross-section B2, no first P-GaN structure 82 is disposed on the surface of the barrier layer 4 away from the GaN channel layer 3, and the metal anode 81 is completely located on the surface of the barrier layer 4 away from the GaN channel layer 3 and covers a portion of the surface of the barrier layer 4 away from the GaN channel layer 3. In the second direction A2, the width of the metal anode 81 is the same as the width of the barrier layer 4, and the proportion of the first P-GaN structure 82 on the surface of the barrier layer 4 away from the GaN channel layer 3 is between 10% and 90%.

[0028] Specifically, in this embodiment, see Figure 3 and Figure 4 The first P-GaN structure 82 is located between the gate structure 6 and the drain 7. The first P-GaN structure 82 is spaced apart from the gate structure 6, and the first P-GaN structure 82 is spaced apart from the drain 7, as shown below. Figure 3 As shown, on the first cross section B1, the metal anode 81 covers the first end of the first P-GaN structure 82 near the gate structure 6 and is located on the surface of the first P-GaN structure 82 away from the barrier layer 4. On the first cross section B1, the metal anode 81 is completely located on the surface of the first P-GaN structure 82 away from the barrier layer 4, and does not cover the surface of the barrier layer 4 away from the GaN channel layer 3, so that the metal anode 81 and the first P-GaN structure 82 can achieve effective contact.

[0029] It is understood that in this embodiment, the multiple first P-GaN structures 82 are arranged in a comb-like pattern, which is not constrained by the voltage withstand capability and on-resistance. The two-dimensional electron gas in the GaN channel layer 3 below the barrier layer 4 covered by the first P-GaN structure 82 is partially consumed by the first P-GaN structure 82, but the two-dimensional electron gas in the GaN channel layer 3 below the barrier layer 4 not covered by the first P-GaN structure 82 will not be depleted, and the GaN HEMT device 100 will still conduct normally. The multiple first P-GaN structures 82 of the reverse freewheeling diode 8 of the GaN HEMT device 100 are arranged in a comb-like pattern, so that the on-resistance of the GaN HEMT device 100 is not affected by the doping concentration and thickness of the first P-GaN structure 82. The parameters of the first P-GaN structure 82 can be adjusted more freely, which is beneficial for better adjustment of the electric field, improving the voltage withstand capability of the GaN HEMT device 100, and reducing the Schottky leakage current.

[0030] See Figure 5 and Figure 6 In another embodiment, the first P-GaN structure 82 is still located between the gate structure 6 and the drain 7. On the first cross section B1, the metal anode 81 covers the surface of the first P-GaN structure 82 away from the barrier layer 4 and is spaced apart from the first end and the second end of the first P-GaN structure 82. The first end of the first P-GaN structure 82 is the end closer to the gate structure 6, and the second end is the end closer to the drain 7 structure. That is, on the first cross section B1, the metal anode 81 is completely located on the surface of the first P-GaN structure 82 away from the barrier layer 4. A part of the first P-GaN structure 82 is located on the side of the metal anode 81 closer to the gate structure 6, and the other part is located on the side of the metal anode 81 closer to the drain 7, ensuring effective contact between the metal anode 81 and the first P-GaN structure 82. Specifically, the first P-GaN structure 82 extends towards the gate structure 6 from its first end near the gate structure 6, and the first end of the first P-GaN structure 82 can be in contact with the gate structure 6. In particular, the first end of the first P-GaN structure 82 can be in contact with the second P-GaN structure 61 of the gate structure 6, and the second end of the first P-GaN structure 82 is spaced apart from the drain 7.

[0031] In other embodiments, the first end of the first P-GaN structure 82 may also be spaced apart from the gate structure 6, and the second end of the first P-GaN structure 82 near the drain 7 may also extend toward the drain 7 and be in contact with the drain 7. The metal anode 81 may be spaced apart from the drain 7. Alternatively, the first P-GaN structure 82 may also be spaced apart from both the gate structure 6 and the drain 7.

[0032] See Figure 7 and Figure 8In another embodiment, the first P-GaN structure 82 is located between the gate structure 6 and the drain 7, with the first P-GaN structure 82 and the gate structure 6 spaced apart, and the first P-GaN structure 82 and the drain 7 spaced apart. On the first cross-section B1, along the third direction A3, a portion of the metal anode 81 covers the first end of the first P-GaN structure 82 near the gate structure 6 and is located on the surface of the first P-GaN structure 82 away from the barrier layer 4, while another portion of the metal anode 81 covers the end face of the first P-GaN structure 82 near the first end of the gate structure 6. That is, on the first cross-section B1, the metal anode 81 is partially located on the surface of the first P-GaN structure 82 away from the barrier layer 4 and partially located on the surface of the barrier layer 4 away from the GaN channel layer 3. The metal anode 81 is in contact with both the barrier layer 4 and the first P-GaN structure 82, allowing for more effective contact between the metal anode 81 and the first P-GaN structure 82, thus ensuring the dynamic characteristics of the GaN HEMT device 100.

[0033] See Figure 9 and Figure 10 In another embodiment, both the metal anode 81 and the first P-GaN structure 82 are disposed on the surface of the barrier layer 4 away from the GaN channel layer 3. In the first cross-section B1, the metal anode 81 is located between the gate structure 6 and the first P-GaN structure 82, with the first P-GaN structure 82 located on the side of the metal anode 81 near the drain 7. The metal anode 81 covers the end face of the first P-GaN structure 82 near the first end of the gate structure 6. Specifically, in the first cross-section B1, the metal anode 81 and the first P-GaN structure 82 are adjacent, and the end face of the first P-GaN structure 82 near the gate structure 6 is in contact with the surface of the metal anode 81 near the drain 7. In the second cross-section B2, the metal anode 81 covers a portion of the surface of the barrier layer 4 away from the GaN channel layer 3. The first P-GaN structure 82 and the drain 7 can be spaced apart or extend to contact the drain 7.

[0034] In this embodiment, the metal anode 81 forms an effective ohmic contact with the first P-GaN structure 82. On the third-direction A3, the length of the metal anode 81 of the reverse freewheeling diode 8 is matched with the process, and can be the same as the length of the gate 62 or the drain 7, or it can be slightly longer than the length of the gate 62 or the drain 7. In other embodiments, the first P-GaN structure 82 can also be configured with other shapes.

[0035] The doping concentration of the first P-GaN structure 82 can differ from that of the second P-GaN structure 61. For example, the doping concentration of the first P-GaN structure 82 can be in the range of 1E16-5E19, and the doping concentration of the second P-GaN structure 61 can be in the range of 1E17-1E19. Alternatively, the doping concentration of the second P-GaN structure 61 can also be in the range of 1E17-1E18, resulting in good performance for the GaNHEMT device 100. In other embodiments, the doping concentration of the first P-GaN structure 82 can be the same as that of the second P-GaN structure 61, wherein the thicknesses of the first P-GaN structure 82 and the second P-GaN structure 61 can be the same or different. Specifically, the first P-GaN structure 82 and the second P-GaN structure 61 can be formed from the same P-GaN layer, which helps to reduce process complexity and difficulty. Compared to using different P-GaN layers to prepare the first P-GaN structure 82 and the second P-GaN structure 61, this simplifies the process.

[0036] In one specific embodiment, the plurality of first P-GaN structures 82 of the reverse freewheeling diode 8 are equally spaced along the second direction A2, with equal spacing between adjacent first P-GaN structures 82. Specifically, the spacing between adjacent first P-GaN structures 82 is in the range of 50 nm to 5 μm, and the width of each first P-GaN structure 82 can also be set in the range of 50 nm to 5 μm, thereby improving the performance of the GaN HEMT device 100, reducing parasitic parameters, and saving chip area. In other embodiments, the plurality of P-GaN structures may also be unequally spaced, and the spacing between adjacent first P-GaN structures 82 may also be set to other values.

[0037] See Figure 11 , Figure 11 This is a schematic flowchart of the fabrication method of the GaN HEMT device provided in this application.

[0038] See Figure 11 This application also provides a method for fabricating a GaN HEMT device 100, the method comprising:

[0039] S1: Provide substrate 1, and prepare a nitride epitaxial layer on substrate 1.

[0040] Specifically, a substrate 1 is provided, and a nitride epitaxial layer is formed on one surface of the substrate 1. The nitride epitaxial layer includes a buffer layer 2, a GaN channel layer 3, a barrier layer 4, and a P-GaN layer stacked sequentially. The material of the barrier layer 4 includes GaN. The nitride epitaxial layer can be formed by methods such as vapor deposition and sputtering.

[0041] S2: Etch the P-GaN layer of the nitride epitaxial layer to form the first P-GaN structure 82 and the second P-GaN structure 61.

[0042] Specifically, the P-GaN layer in the nitride epitaxial layer prepared in step S1 is selectively etched to form multiple first P-GaN structures 82 and second P-GaN structures 61. The multiple first P-GaN structures 82 are arranged in a comb-like pattern, and along the second direction A2, they are parallel and spaced apart. Along the third direction A3, the multiple first P-GaN structures 82 and second P-GaN structures 61 can be spaced apart or in contact. It can be understood that in this embodiment, the comb-like arrangement of the multiple first P-GaN structures 82 effectively solves the problems of large reverse leakage current and poor withstand voltage in integrated Schottky diodes in the prior art.

[0043] S3: The source electrode 5 and the drain electrode 7 are fabricated on the surface of the barrier layer 4 away from the GaN channel layer 3.

[0044] Specifically, after step S2, metal is deposited on the surface of the barrier layer 4 of the nitride epitaxial layer away from the GaN channel layer 3, and the deposited metal forms an effective ohmic contact with the barrier layer 4. The deposited metal is spaced apart from the first P-GaN structure 82 and the second P-GaN structure 61, and along the second direction A2, a portion of the deposited metal is located on the side of the second P-GaN structure 61 away from the first P-GaN structure 82, forming the source 5, and a portion is located on the side of the first P-GaN structure 82 away from the second P-GaN structure 61, forming the drain 7. That is, the first P-GaN structure 82 and the second P-GaN structure 61 are located between the source 5 and the drain 7, and the first P-GaN structure 82 is located on the side of the second P-GaN structure 61 closer to the drain 7.

[0045] S4: Preparation of metal anode 81.

[0046] Specifically, metal is deposited on the surfaces of the multiple first P-GaN structures 82 away from the barrier layer 4 and on the surfaces of the barrier layer 4 away from the GaN channel layer 3. Along the second direction A2, the deposited metal partially covers the surfaces of the first P-GaN structures 82 away from the barrier layer 4 and partially covers the surfaces of the barrier layer 4 away from the GaN channel layer 3 between two adjacent first P-GaN structures 82. The deposited metal forms an ohmic contact with the first P-GaN structures 82 and a Schottky contact with the barrier layer 4. In the third direction A3, the deposited metal is spaced apart from the source electrode 5 and the drain electrode 7 to form a metal anode 81. The metal anode 81 and the multiple first P-GaN structures 82 form a reverse freewheeling diode 8.

[0047] S5: A gate 62 is fabricated on the surface of the second P-GaN structure 61 away from the barrier layer 4.

[0048] Specifically, metal is deposited on the surface of the second P-GaN structure 61 away from the barrier layer 4, so that the metal completely covers the second P-GaN structure 61. The deposited metal forms a Schottky contact with the second P-GaN structure 61 to form the gate 62.

[0049] Using the above method, the GaN HEMT device 100 provided in this application can be finally fabricated, which helps to solve the problems of large reverse leakage current and poor withstand voltage of integrated Schottky diodes in the prior art.

[0050] This application discloses a GaN HEMT device 100. The GaN HEMT device 100 provided in this application integrates a reverse freewheeling diode 8, which includes multiple spaced first P-GaN structures 82. This results in the GaN HEMT device 100 having lower reverse conduction loss, higher withstand voltage, lower leakage current, and lower parasitic parameters, saving chip area and effectively solving the problems of large reverse leakage current and poor withstand voltage of integrated Schottky diodes in the prior art.

[0051] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A GaN HEMT device, comprising a substrate, a buffer layer, a GaN channel layer, and a barrier layer sequentially stacked along a first direction; wherein a source, a gate structure, and a drain are disposed on the surface of the barrier layer away from the GaN channel layer, the gate structure being disposed between the source and the drain; characterized in that, It also includes a reverse freewheeling diode integrated on the surface of the barrier layer away from the GaN channel layer. The reverse freewheeling diode is disposed between the gate structure and the drain, and includes a metal anode and a plurality of first P-GaN structures. The metal anode is spaced apart from the gate structure, and each first P-GaN structure is at least partially located on the side of the metal anode near the drain. The plurality of first P-GaN structures are contacted with the metal anode and arranged in a comb-like pattern. The first P-GaN structures are disposed on the surface of the barrier layer away from the GaN channel layer. The metal anode extends along a second direction, and the plurality of first P-GaN structures are parallel to each other and spaced apart in the second direction. Each first P-GaN structure extends along a third direction. The metal anode forms a Schottky contact with the barrier layer and an ohmic contact with the first P-GaN structures. Wherein, the third direction is the direction extending from the source to the drain, and the second direction is the direction perpendicular to the third direction and the first direction.

2. The GaN HEMT device according to claim 1, characterized in that, Along the second direction, the metal anode is in contact with both the surface of the first P-GaN structure away from the barrier layer and the surface of the barrier layer away from the GaN channel layer, and a portion of the metal anode covers part of the first P-GaN structure, while another portion of the metal anode covers part of the barrier layer; The GaN HEMT device includes a first cross section and a second cross section that are spaced apart and parallel to each other in the second direction. On the first cross section, the metal anode covers a portion of the surface of the first P-GaN structure away from the barrier layer. On the second cross section, the metal anode covers a portion of the surface of the barrier layer away from the GaN channel layer.

3. The GaN HEMT device according to claim 2, characterized in that, The first P-GaN structure is spaced apart from the gate structure, and the first P-GaN structure is spaced apart from the drain. On the first cross section, the metal anode covers the first end of the first P-GaN structure near the gate structure and is located on the surface of the first P-GaN structure away from the barrier layer. or On the first cross section, along the third direction, a portion of the metal anode covers the first end of the first P-GaN structure near the gate structure and is located on the surface of the first P-GaN structure away from the barrier layer, while another portion of the metal anode covers the end face of the first P-GaN structure near the first end of the gate structure.

4. The GaN HEMT device according to claim 2, characterized in that, On the first cross section, the metal anode covers the surface of the first P-GaN structure away from the barrier layer and is spaced apart from the first end and the second end of the first P-GaN structure; the first end of the first P-GaN structure extends toward the gate structure near the gate structure and is in contact with the gate structure.

5. The GaN HEMT device according to claim 1, characterized in that, Both the metal anode and the first P-GaN structure are disposed on the surface of the barrier layer away from the GaN channel layer, and the first P-GaN structure is located on the side of the metal anode closer to the drain. The GaN HEMT device includes a first cross section and a second cross section spaced apart and parallel to each other in the second direction. On the first cross section, the end face of the first P-GaN structure near the first end of the gate structure is in contact with the surface of the metal anode near the drain. On the second cross section, the metal anode covers a portion of the surface of the barrier layer away from the GaN channel layer.

6. The GaN HEMT device according to claim 1, characterized in that, The second end of the first P-GaN structure near the drain extends toward the drain and is in contact with the drain, while the metal anode is spaced apart from the drain.

7. The GaN HEMT device according to claim 1, characterized in that, The gate structure includes a stacked second P-GaN structure and a gate. The second P-GaN structure is disposed on the surface of the barrier layer away from the GaN channel layer, and the gate is disposed on the surface of the second P-GaN structure away from the barrier layer. The source forms an ohmic contact with the barrier layer, the drain forms an ohmic contact with the barrier layer, and the gate forms an ohmic contact or a Schottky contact with the second P-GaN structure. The metal anode is electrically connected to the source. The second P-GaN structure has the same doping concentration as the first P-GaN structure, and the second P-GaN structure has the same thickness as the first P-GaN structure.

8. The GaN HEMT device according to claim 7, characterized in that, The second P-GaN structure and the first P-GaN structure are formed by the same P-GaN layer.

9. The GaN HEMT device according to claim 1, characterized in that, When the GaN HEMT device is forward-biased, the drain is at a positive voltage, the reverse freewheeling diode is in a turned-off state, and the GaN channel layer corresponding to the position of the barrier layer not covered by the first P-GaN structure has a two-dimensional electron gas.

10. The GaN HEMT device according to claim 1, characterized in that, The barrier layer is made of AlGaN; along the second direction, a plurality of the first P-GaN structures cover 10%-90% of the surface of the barrier layer away from the GaN channel layer.

11. The GaN HEMT device according to claim 1, characterized in that, Multiple first P-GaN structures are arranged at equal intervals in the second direction, with the spacing between two adjacent first P-GaN structures being 50nm-5um.

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