Algan / gan power heit device and method of manufacturing the same

Abstract

The application provides an AlGaN / GaN power HEMT device and a preparation method thereof, and the device comprises an n-type GaN substrate, a first p-type GaN layer, an AlGaN layer, a hole injection type PN junction layer and a gate structure, the gate structure penetrates through the hole injection type PN junction layer, the AlGaN layer and the first p-type GaN layer, and stops in the n-type GaN substrate, and comprises a gate metal aluminum layer and a gate silicon dioxide layer; the hole injection type PN junction layer comprises a second p-type GaN layer and a second n-type GaN layer which are distributed along a horizontal direction, and the second n-type GaN layer is located on a side close to the gate structure. The AlGaN / GaN power HEMT device provided by the application introduces a brand-new structure design, compared with a traditional U-shaped GaN MOS tube, the channel structure is designed as a longitudinal direction, the electric field distribution near the trench gate structure is changed, the electric field concentration phenomenon is relieved, and the breakdown voltage and the withstand voltage of the HEMT device are improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to an AlGaN / GaN power HEMT device and its fabrication method. Background Technology

[0002] Power semiconductor devices are widely used in power converters such as DC converters, frequency converters, rectifiers and inverters. They have excellent power control performance and play an irreplaceable role in power systems, photovoltaic power generation systems and hybrid locomotives.

[0003] Currently, most power semiconductor devices employ silicon-based diodes, power MOSFET transistors, and IGBTs (Insulated Gate Bipolar Transistors). As Si-based power semiconductor devices gradually reach their theoretical limits, the pace of upgrades for existing power semiconductor devices is slowing down. At the current research level for Si-based devices, it is difficult to further achieve high-frequency, high-power-density, and miniaturized converters. Gallium nitride (GaN), a wide-bandgap semiconductor material, possesses characteristics such as high critical breakdown electric field, high saturation electron velocity, high electron density, high electron mobility, and high thermal conductivity. It is a semiconductor material with high radiation resistance suitable for high-frequency, high-voltage, high-temperature, and high-power applications. GaN devices are the most critical semiconductor devices in next-generation radar and communication systems, and are also the main devices used in next-generation semiconductor lighting. HEMTs (High Electron Mobility Transistors) are heterojunction field-effect transistors. GaN HEMTs achieve high current density and high electron saturation drift velocity through the AlGaN / GaN heterojunction, making them suitable for high-frequency switching.

[0004] However, existing GaN devices still have significant room for improvement in terms of breakdown voltage and withstand voltage. For example, traditional U-shaped GaN MOSFETs exhibit electric field concentration in the trench bottom region, limiting the improvement of device breakdown voltage. Optimizing the channel structure, altering the electric field distribution near the trench gate structure, and alleviating electric field concentration are urgent problems to be solved in optimizing the breakdown characteristics of GaN devices.

[0005] Therefore, it is necessary to propose a new AlGaN / GaN power HEMT device and its fabrication method to solve the above problems. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an AlGaN / GaN power HEMT device and its fabrication method, which solves the problem that electric field concentration exists in the bottom region of the trench in traditional U-shaped GaN MOS transistors, limiting the improvement of device breakdown voltage.

[0007] To achieve the above and other related objectives, the present invention provides an AlGaN / GaN power HEMT device, comprising:

[0008] n-type GaN substrate;

[0009] A first p-type GaN layer is formed on the n-type GaN substrate;

[0010] An AlGaN layer formed above the first p-type GaN layer;

[0011] A hole-injection PN junction layer is formed above the AlGaN layer;

[0012] A gate structure extends through the hole-injection PN junction layer, the AlGaN layer, and the first p-type GaN layer, and terminates in the n-type GaN substrate. The gate structure includes a gate aluminum layer and a gate silicon dioxide layer formed on the sidewalls and below the gate aluminum layer. The hole-injection PN junction layer includes a second p-type GaN layer and a second n-type GaN layer distributed in a horizontal direction, with the second n-type GaN layer located on the side closest to the gate structure.

[0013] As an optional embodiment of the present invention, the thickness of the n-type GaN substrate ranges from 5 to 10 μm.

[0014] As an optional embodiment of the present invention, the doping concentration of the n-type GaN substrate is in the range of 1×10⁻⁶. 15 -5×10 15 cm -3 ;

[0015] As an optional embodiment of the present invention, the thickness of the first p-type GaN layer ranges from 0.5 to 1.5 μm;

[0016] As an optional embodiment of the present invention, the doping concentration range of the first p-type GaN layer is 1×10⁻⁶. 16 -1×10 17 cm -3 .

[0017] As an optional embodiment of the present invention, the thickness of the AlGaN layer ranges from 0.05 to 0.15 μm.

[0018] As an optional embodiment of the present invention, the doping concentration of the AlGaN layer is in the range of 5 × 10⁻⁶. 14 -5×10 15 cm -3 between.

[0019] As an optional embodiment of the present invention, the thickness of the hole-injection type PN junction layer ranges from 0.5 to 1.5 μm.

[0020] As an optional embodiment of the present invention, the doping concentration range of the second p-type GaN layer is 1×10⁻⁶. 17 -1×10 18 cm -3 .

[0021] As an optional embodiment of the present invention, the doping concentration range of the second n-type GaN layer is 1×10⁻⁶. 18 -1×10 19 cm -3 .

[0022] As an optional embodiment of the present invention, the thickness of the gate metal aluminum layer ranges from 0.5 to 5 μm.

[0023] As an optional embodiment of the present invention, the thickness of the gate silicon dioxide layer ranges from 0.5 to 5 μm.

[0024] As an optional embodiment of the present invention, the AlGaN / GaN power HEMT device further includes a first n-type GaN layer formed under the n-type GaN substrate, wherein the first n-type GaN layer is led out as the drain of the AlGaN / GaN power HEMT device.

[0025] As an optional embodiment of the present invention, the thickness of the first n-type GaN layer ranges from 0.5 to 1.5 μm, and the doping concentration of the first n-type GaN layer ranges from 1 × 10⁻⁶. 18 -5×10 18 cm -3 .

[0026] As an optional embodiment of the present invention, the AlGaN / GaN power HEMT device further includes a source metal layer formed above the hole-injected PN junction layer.

[0027] As an optional embodiment of the present invention, the thickness of the source metal layer ranges from 0.05 to 0.15 μm.

[0028] As an optional embodiment of the present invention, the source metal layer includes a horizontally distributed aluminum layer and a gold layer, the aluminum layer being located on the side close to the gate structure, and the gold layer being led out as the source of the AlGaN / GaN power HEMT device.

[0029] As an optional embodiment of the present invention, the junction of the aluminum layer and the gold layer is located above the second n-type GaN layer.

[0030] This invention also provides a method for fabricating an AlGaN / GaN power HEMT device, comprising the following steps:

[0031] Provide n-type GaN substrates;

[0032] A first p-type GaN layer, an AlGaN layer, and a hole-injection PN junction layer are sequentially formed on the n-type GaN substrate.

[0033] A gate structure is formed that penetrates the hole-injection PN junction layer, the AlGaN layer, and the first p-type GaN layer, and terminates in the n-type GaN substrate. The gate structure includes a gate aluminum layer and a gate silicon dioxide layer formed on the sidewalls and below the gate aluminum layer. The hole-injection PN junction layer includes a second p-type GaN layer and a second n-type GaN layer distributed in a horizontal direction, with the second n-type GaN layer located on the side closest to the gate structure.

[0034] As an optional embodiment of the present invention, the method for fabricating the AlGaN / GaN power HEMT device further includes the step of forming a first n-type GaN layer under the n-type GaN substrate, wherein the first n-type GaN layer is led out as the drain of the AlGaN / GaN power HEMT device.

[0035] As an optional embodiment of the present invention, the fabrication method of the AlGaN / GaN power HEMT device further includes the step of forming a source metal layer above the hole-injected PN junction layer.

[0036] As an optional embodiment of the present invention, the source metal layer includes a horizontally distributed aluminum layer and a gold layer, the aluminum layer being located on the side close to the gate structure, and the gold layer being led out as the source of the AlGaN / GaN power HEMT device.

[0037] As an optional embodiment of the present invention, the junction of the aluminum layer and the gold layer is located above the second n-type GaN layer.

[0038] As described above, the AlGaN / GaN power HEMT device and its fabrication method provided by the present invention have the following beneficial effects:

[0039] The AlGaN / GaN power HEMT device provided by this invention introduces a novel structural design. Compared with the traditional U-shaped GaN MOS transistor, the channel structure is designed vertically, which changes the electric field distribution near the trench gate structure. This can effectively alleviate the electric field concentration phenomenon and improve the breakdown voltage and withstand voltage of the HEMT device. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the AlGaN / GaN power HEMT device provided in Embodiment 1 of the present invention.

[0041] Figure 2 This is a breakdown voltage characteristic curve of the AlGaN / GaN power HEMT device provided in Embodiment 1 of the present invention.

[0042] Figure 3 This is a transfer characteristic curve of the AlGaN / GaN power HEMT device provided in Embodiment 1 of the present invention.

[0043] Figure 4 This is an output characteristic curve of the AlGaN / GaN power HEMT device provided in Embodiment 1 of the present invention.

[0044] Figure 5 This is a schematic diagram of the n-type GaN substrate provided in Embodiment 2 of the present invention.

[0045] Figure 6 This is a schematic diagram of a first p-type GaN layer, an AlGaN layer, and a hole-injection PN junction layer sequentially formed on an n-type GaN substrate in Embodiment 2 of the present invention.

[0046] Figure 7 This is a schematic diagram of the gate structure formed in Embodiment 2 of the present invention.

[0047] Figure 8 This is a schematic diagram of the formation of the source metal layer in Embodiment 2 of the present invention.

[0048] Component designation explanation

[0049] 101 Gate silicon dioxide layer

[0050] 102 Gate metal aluminum layer

[0051] 103 Aluminum Metal Layer

[0052] 104 Metallic Gold Layer

[0053] 105 Second p-type GaN layer

[0054] 106 Second n-type GaN layer

[0055] 107 AlGaN layers

[0056] 108 First p-type GaN layer

[0057] 109 n-type GaN substrate

[0058] 110 First n-type GaN layer

[0059] G gate

[0060] S source pole

[0061] D drain Detailed Implementation

[0062] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0063] Please see Figures 1 to 8 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the shape, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0064] Example 1

[0065] Please see Figures 1 to 4 This embodiment provides an AlGaN / GaN power HEMT device, including:

[0066] n-type GaN substrate 109;

[0067] A first p-type GaN layer 108 is formed on the n-type GaN substrate 109;

[0068] An AlGaN layer 107 is formed above the first p-type GaN layer 108;

[0069] A hole-injection type PN junction layer is formed above the AlGaN layer 107;

[0070] A gate structure extends through the hole-injection PN junction layer, the AlGaN layer 107, and the first p-type GaN layer 108, and terminates in the n-type GaN substrate 109. The gate structure includes a gate aluminum layer 102 and a gate silicon dioxide layer 101 formed on the sidewalls and below the gate aluminum layer 102. The hole-injection PN junction layer includes a second p-type GaN layer 105 and a second n-type GaN layer 106 distributed in a horizontal direction. The second n-type GaN layer 106 is located on the side close to the gate structure. The gate aluminum layer 102 is led out as the gate G.

[0071] The AlGaN / GaN power HEMT device provided by this invention introduces a novel structural design. Compared with the traditional U-shaped GaN MOS transistor, the channel structure is designed vertically, which changes the electric field distribution near the trench gate structure. This can effectively alleviate the electric field concentration phenomenon and improve the breakdown voltage and withstand voltage of the HEMT device.

[0072] As an example, the thickness of the n-type GaN substrate 109 ranges from 5 to 10 μm (inclusive; unless otherwise specified, descriptions of numerical ranges in this specification refer to values ​​including the endpoints), and its doping concentration ranges from 1 × 10⁻⁶. 15 -5×10 15 cm -3 .

[0073] As an example, the thickness of the first p-type GaN layer 108 ranges from 0.5 to 1.5 μm, and its doping concentration ranges from 1 × 10⁻⁶. 16 -1×10 17 cm -3 .

[0074] As an example, the thickness of the AlGaN layer 107 ranges from 0.05 to 0.15 μm, and its doping concentration ranges from 5 × 10⁻⁶. 14 -5×10 15 cm -3 .

[0075] As an example, the thickness of the hole-injected PN junction layer ranges from 0.5 to 1.5 μm, and the doping concentration of the second p-type GaN layer 105 ranges from 1 × 10⁻⁶. 17 -1×10 18 cm -3 The doping concentration range of the second n-type GaN layer 106 is 1×10⁻⁶. 18 -1×10 19 cm -3 .

[0076] As an example, the thickness of the gate aluminum layer 102 ranges from 0.5 to 5 μm, and the thickness of the gate silicon dioxide layer 101 ranges from 0.5 to 5 μm.

[0077] As an example, such as Figure 1 As shown, the AlGaN / GaN power HEMT device further includes a first n-type GaN layer 110 formed under the n-type GaN substrate, and the first n-type GaN layer 110 is led out as the drain D of the AlGaN / GaN power HEMT device.

[0078] As an example, such as Figure 1 As shown, the thickness of the first n-type GaN layer 110 ranges from 0.5 to 1.5 μm, and its doping concentration ranges from 1 × 10⁻⁶. 18 -5×10 18 cm -3 .

[0079] As an example, such as Figure 1As shown, the AlGaN / GaN power HEMT device further includes a source metal layer formed above the hole-injection PN junction layer. In a preferred example, the thickness of the source metal layer ranges from 0.05 to 0.15 μm.

[0080] As an example, such as Figure 1 As shown, the source metal layer includes a horizontally distributed aluminum layer 103 and a gold layer 104. The aluminum layer 103 is located near the gate structure, and the gold layer 104 is led out as the source S of the AlGaN / GaN power HEMT device. In a preferred example, the junction between the aluminum layer 103 and the gold layer 104 is located above the second n-type GaN layer.

[0081] As an example, in this embodiment, the n-type GaN substrate 109 has a thickness of 8 μm and a doping concentration of 2 × 10⁻⁶. 15 cm -3 Preferably, the thickness of the first p-type GaN layer 108 is 1 μm, and its doping concentration is 5 × 10⁻⁶. 16 cm -3 The AlGaN layer 107 has a thickness of 0.1 μm and a doping concentration of 2 × 10⁻⁶. 18 cm -3 The hole-injection type PN junction layer has a thickness of 1 μm, meaning that the thickness of both the second p-type GaN layer 105 and the second n-type GaN layer 106 is 1 μm. The doping concentration of the second p-type GaN layer 105 is 4 × 10⁻⁶. 17 cm -3 The doping concentration of the second n-type GaN layer 106 is 2 × 10⁶. 18 cm -3 The gate aluminum layer 102 has a thickness of 2.2 μm, and the gate silicon dioxide layer 101 has a thickness of 2.3 μm. The first n-type GaN layer 110 has a thickness of 1 μm and a doping concentration of 2 × 10⁻⁶. 18 cm -3 The thickness of the source metal layer is 0.1 μm, meaning that the thickness of both the aluminum layer 103 and the gold layer 104 is 0.1 μm.

[0082] The AlGaN / GaN power HEMT device provided in this embodiment is an enhancement-mode GaN transistor structure with a maximum withstand voltage of 860V. For example... Figure 1As shown, the AlGaN / GaN power HEMT device has a vertical structure, using the first n-type GaN layer 110 as the substrate material and the n-type GaN substrate 109 as the transition layer and drift region, with a thickness of 8 μm. The second n-type GaN layer 106 and the AlGaN layer 107 are epitaxially grown on the n-type GaN substrate 109. The AlGaN / GaN heterojunction forms a conductive two-dimensional electron gas (2DEG), which has high electron mobility and can effectively improve the device's breakdown voltage and thus device power. The hole-injection PN junction layer includes a second p-type GaN layer 105 and a second n-type GaN layer 106 distributed horizontally, which together form a hole-injection PN junction. The gate structure is a trench gate, including a gate aluminum layer 102 and a gate silicon dioxide layer 101 formed on the sidewalls and below the gate aluminum layer 102. The trench width of the trench gate is 2 μm, and the trench depth is 2.3 μm.

[0083] Compared to traditional U-shaped GaN MOSFETs, which are limited by electric field concentration at the bottom of the trench, thus restricting the improvement of device breakdown voltage, the AlGaN / GaN power HEMT device in this embodiment has a vertical channel structure. Its advantage lies in the structural design of the thick drift region and the use of two-dimensional electron gas, thereby optimizing the drift region, changing the electric field distribution near the trench gate structure, alleviating the electric field concentration phenomenon, and thus improving the breakdown characteristics of the U-shaped AlGaN / GaN power HEMT device and increasing the device figure of merit.

[0084] like Figure 2 The figure shown is a breakdown voltage characteristic curve of the AlGaN / GaN power HEMT device provided in this embodiment. As a type of power device, the AlGaN / GaN power HEMT device needs to withstand high voltages in the off-state. This capability can be measured by its breakdown voltage. For AlGaN / GaN power HEMT devices, the leakage current is typically higher than 50 mA / cm². 2 The corresponding drain voltage is called the breakdown voltage. For example... Figure 2 As shown, in this embodiment, the breakdown voltage of the AlGaN / GaN power HEMT device is as high as 860V, which far exceeds the breakdown voltage of existing conventional U-shaped GaN MOS transistors. At this point, the device is not damaged, and the withstand voltage curve is repeatable, i.e., it is a soft breakdown.

[0085] like Figure 3 The figure shown is a transfer characteristic curve of the AlGaN / GaN power HEMT device provided in this embodiment. The transfer characteristic of the device represents the relationship between the drain current ID and the gate voltage VGS under a fixed drain voltage VDS, which can reflect the amplification capability of the device. Figure 3This is the transition curve of the AlGaN / GaN power HEMT device in this embodiment in linear coordinates, with drain voltage V. DS =1V. From Figure 3 The transfer characteristic curves in the figure can yield values ​​such as threshold voltage VTH, saturation current, and on / off ratio I. ON / I OFF And important parameters such as subthreshold swing S. It can be seen that the above parameters are also superior to those of existing traditional U-type GaNMOS transistors.

[0086] like Figure 4 The figure shown is the output characteristic curve of the AlGaN / GaN power HEMT device provided in this embodiment. The output characteristic curve can be understood as the drain current-voltage characteristic, that is, the drain current I. D With leakage pressure V DS The changing relationship. For example... Figure 4 As shown, the region is divided into linear, nonlinear, and saturation regions. By changing the gate voltage, a series of output curves can be obtained, thereby extracting the on-resistance R of the device. ON Parameters such as these. Figure 4 In the diagram, GaN_1, GaN_2, and GaN_3 are the output curves obtained under different gate voltages.

[0087] The AlGaN / GaN power HEMT device provided in this embodiment has a small allowable range of gate-source voltage variation and a small maximum on-resistance, resulting in low thermal resistance and suitability for high-temperature environments. When the gate-source voltage is 0 and the transistor is reverse-biased, the source-drain forward voltage drop of the AlGaN / GaN power HEMT device is larger than that of a silicon-based MOSFET transistor. In LCC resonant converter applications, it exhibits lower losses compared to silicon-based MOSFET transistors.

[0088] Example 2

[0089] Please see Figures 5 to 8 This embodiment provides a method for fabricating an AlGaN / GaN power HEMT device, including the following steps:

[0090] 1) Provide an n-type GaN substrate 109;

[0091] 2) A first p-type GaN layer 108, an AlGaN layer 107, and a hole-injection type PN junction layer are sequentially formed on the n-type GaN substrate 109;

[0092] 3) A gate structure is formed that penetrates the hole-injection PN junction layer, the AlGaN layer 107 and the first p-type GaN layer 108 and stops in the n-type GaN substrate 109. The gate structure includes a gate aluminum metal layer 102 and a gate silicon dioxide layer 101 formed on the sidewall and below the gate aluminum metal layer 102. The hole-injection PN junction layer includes a second p-type GaN layer 105 and a second n-type GaN layer 106 distributed in a horizontal direction. The second n-type GaN layer 106 is located on the side close to the gate structure.

[0093] In step 1), as Figure 5 As shown, an n-type GaN substrate 109 is provided. In a preferred example, a first n-type GaN layer 110 is further formed beneath the n-type GaN substrate 109, and the first n-type GaN layer 110 leads out as the drain D of the AlGaN / GaN power HEMT device. The first n-type GaN layer 110 has a higher doping concentration than the n-type GaN substrate 109. The n-type GaN substrate 109 and the first n-type GaN layer 110 can be obtained by sequential epitaxial growth on an epitaxial substrate.

[0094] In step 2), as Figure 6 As shown, a first p-type GaN layer 108, an AlGaN layer 107, and a hole-injected PN junction layer are sequentially formed above the n-type GaN substrate 109. The hole-injected PN junction layer includes a second p-type GaN layer 105 and a second n-type GaN layer 106 distributed horizontally, with the second n-type GaN layer 106 located on the side closest to the gate structure. The method for forming the first p-type GaN layer 108, the AlGaN layer 107, and the hole-injected PN junction layer includes epitaxial growth of the required material layers and obtaining the desired doping concentration through diffusion or ion implantation. The boundary between the second p-type GaN layer 105 and the second n-type GaN layer 106 can be defined by photolithography, and GaN layers with opposite doping types can be obtained by ion implantation of the p-type GaN layer or the n-type GaN layer.

[0095] In step 3), as Figure 7 As shown, a gate structure is formed that penetrates the hole-injection PN junction layer, the AlGaN layer 107 and the first p-type GaN layer 108, and stops in the n-type GaN substrate 109. The gate structure includes a gate aluminum metal layer 102 and a gate silicon dioxide layer 101 formed on the sidewalls and below the gate aluminum metal layer 102.

[0096] As an example, such as Figure 8As shown, the fabrication method of the AlGaN / GaN power HEMT device further includes the step of forming a source metal layer above the hole-injection type PN junction layer. In a preferred example, the source metal layer includes a horizontally distributed aluminum layer 103 and a gold layer 104, with the aluminum layer 103 located near the gate structure and the gold layer 104 leading out as the source of the AlGaN / GaN power HEMT device. The junction between the aluminum layer 103 and the gold layer 104 is located above the second n-type GaN layer 106. The process for forming the source metal layer includes, but is not limited to, PVD process.

[0097] In a preferred example, in this embodiment, the n-type GaN substrate 109 has a thickness of 8 μm and a doping concentration of 2 × 10⁻⁶. 15 cm -3 The thickness of the first p-type GaN layer 108 is preferably 1 μm, and its doping concentration is 5 × 10⁻⁶. 16 cm -3 The AlGaN layer 107 has a thickness of 0.1 μm and a doping concentration of 2 × 10⁻⁶. 18 cm -3 The hole-injection type PN junction layer has a thickness of 1 μm, meaning that the thickness of both the second p-type GaN layer 105 and the second n-type GaN layer 106 is 1 μm. The doping concentration of the second p-type GaN layer 105 is 4 × 10⁻⁶. 17 cm -3 The doping concentration of the second n-type GaN layer 106 is 2 × 10⁶. 18 cm -3 The gate aluminum layer 102 has a thickness of 2.2 μm, and the gate silicon dioxide layer 101 has a thickness of 2.3 μm. The first n-type GaN layer 110 has a thickness of 1 μm and a doping concentration of 2 × 10⁻⁶. 18 cm -3 The thickness of the source metal layer is 0.1 μm, meaning that the thickness of both the aluminum layer 103 and the gold layer 104 is 0.1 μm. The AlGaN / GaN power HEMT device designed as described above can optimize the drift region, alter the electric field distribution near the trench gate structure, alleviate electric field concentration, thereby improving the device's breakdown characteristics and increasing its figure of merit.

[0098] In summary, this invention provides an AlGaN / GaN power HEMT device and its fabrication method. The AlGaN / GaN power HEMT device includes: an n-type GaN substrate; a first p-type GaN layer formed on the n-type GaN substrate; an AlGaN layer formed on the first p-type GaN layer; a hole-injection PN junction layer formed on the AlGaN layer; and a gate structure penetrating the hole-injection PN junction layer, the AlGaN layer, and the first p-type GaN layer, and ending in the n-type GaN substrate. The gate structure includes a gate aluminum layer and a gate silicon dioxide layer formed on the sidewalls and below the gate aluminum layer. The hole-injection PN junction layer includes a second p-type GaN layer and a second n-type GaN layer distributed horizontally, with the second n-type GaN layer located on the side closest to the gate structure. The AlGaN / GaN power HEMT device provided by this invention introduces a novel structural design. Compared with the traditional U-shaped GaN MOS transistor, the channel structure is designed vertically, which changes the electric field distribution near the trench gate structure. This can alleviate the electric field concentration phenomenon and improve the breakdown voltage and withstand voltage of the HEMT device.

[0099] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An AlGaN / GaN power HEMT device, characterized in that, include: n-type GaN substrate; A first p-type GaN layer is formed on the n-type GaN substrate; An AlGaN layer formed above the first p-type GaN layer; A hole-injection PN junction layer is formed above the AlGaN layer; A gate structure extends through the hole-injection PN junction layer, the AlGaN layer, and the first p-type GaN layer, and terminates in the n-type GaN substrate. The gate structure includes a gate aluminum layer and a gate silicon dioxide layer formed on the sidewalls and below the gate aluminum layer. The hole-injection PN junction layer includes a second p-type GaN layer and a second n-type GaN layer distributed in a horizontal direction, with the second n-type GaN layer located on the side closest to the gate structure. A source metal layer is formed above the hole-injection PN junction layer. The source metal layer includes a horizontally distributed aluminum layer and a gold layer. The aluminum layer is located on the side close to the gate structure. The gold layer is led out as the source of the AlGaN / GaN power HEMT device. The gold layer serving as the source is in contact with both the second p-type GaN layer and the second n-type GaN layer. The junction between the aluminum layer and the gold layer is located above the second n-type GaN layer. The second n-type GaN layer and the AlGaN layer form an AlGaN / GaN heterojunction, which forms a conductive two-dimensional electron gas with high electron mobility.

2. The AlGaN / GaN power HEMT device according to claim 1, characterized in that, The thickness of the n-type GaN substrate ranges from 5 to 10 μm, and the doping concentration of the n-type GaN substrate ranges from 1 × 10⁻⁶. 15 -5×10 15 cm -3 The thickness of the first p-type GaN layer ranges from 0.5 to 1.5 μm, and the doping concentration of the first p-type GaN layer ranges from 1 × 10⁻⁶. 16 -1×10 17 cm -3 The thickness of the AlGaN layer ranges from 0.05 to 0.15 μm, and the doping concentration of the AlGaN layer ranges from 5 × 10⁻⁶. 14 -5×10 15 cm -3 The thickness of the hole-injected PN junction layer ranges from 0.5 to 1.5 μm, and the doping concentration of the second p-type GaN layer ranges from 1 × 10⁻⁶. 17 -1×10 18 cm -3 The doping concentration range of the second n-type GaN layer is 1×10⁻⁶. 18 -1×10 19 cm -3 The thickness of the gate aluminum layer is in the range of 0.5-5μm, and the thickness of the gate silicon dioxide layer is in the range of 0.5-5μm.

3. The AlGaN / GaN power HEMT device according to claim 1, characterized in that, It also includes a first n-type GaN layer formed beneath the n-type GaN substrate, the first n-type GaN layer being led out as the drain of the AlGaN / GaN power HEMT device.

4. The AlGaN / GaN power HEMT device according to claim 3, characterized in that, The thickness of the first n-type GaN layer ranges from 0.5 to 1.5 μm, and the doping concentration of the first n-type GaN layer ranges from 1 × 10⁻⁶. 18 -5×10 18 cm -3 .

5. The AlGaN / GaN power HEMT device according to claim 1, characterized in that, The thickness of the source metal layer ranges from 0.05 to 0.15 μm.

6. A method for fabricating an AlGaN / GaN power HEMT device, characterized in that, Includes the following steps: Provide n-type GaN substrates; A first p-type GaN layer, an AlGaN layer, and a hole-injection PN junction layer are sequentially formed on the n-type GaN substrate. A gate structure is formed that penetrates the hole-injection PN junction layer, the AlGaN layer, and the first p-type GaN layer, and terminates in the n-type GaN substrate. The gate structure includes a gate aluminum layer and a gate silicon dioxide layer formed on the sidewalls and below the gate aluminum layer. The hole-injection PN junction layer includes a second p-type GaN layer and a second n-type GaN layer distributed in a horizontal direction, with the second n-type GaN layer located on the side closest to the gate structure. The step of forming a source metal layer above the hole-injection PN junction layer; the source metal layer includes a horizontally distributed aluminum layer and a gold layer, the aluminum layer is located on the side close to the gate structure, and the gold layer is led out as the source of the AlGaN / GaN power HEMT device, wherein the gold layer serving as the source is in contact with both the second p-type GaN layer and the second n-type GaN layer, and the junction of the aluminum layer and the gold layer is located above the second n-type GaN layer; The second n-type GaN layer and the AlGaN layer form an AlGaN / GaN heterojunction, which forms a conductive two-dimensional electron gas with high electron mobility.

7. The method for fabricating the AlGaN / GaN power HEMT device according to claim 6, characterized in that, It also includes the step of forming a first n-type GaN layer under the n-type GaN substrate, wherein the first n-type GaN layer is led out as the drain of the AlGaN / GaN power HEMT device.

Images