AlGaN / GaN power HEMT device and manufacturing method thereof

Abstract

The present invention provides an AlGaN / GaN power HEMT device and its manufacturing method. The device includes an n-type GaN substrate, a first p-type GaN layer, an AlGaN layer, a hole injection PN junction layer, and a gate structure, the gate structure penetrates the hole injection PN junction layer, the AlGaN layer, and the first p-type GaN layer, and remains in the n-type GaN substrate, and includes a gate metal aluminum layer and a gate silicon oxide layer, the hole injection PN junction layer includes a second p-type GaN layer and a second n-type GaN layer distributed along the horizontal direction, and the second n-type GaN layer is located on the side closer to the gate structure. Compared with the conventional U-type GaN MOS transistor, the AlGaN / GaN power HEMT device provided by the present invention introduces a new structural design and designs the channel structure vertically, thereby changing the electric field distribution near the trench gate structure, mitigating the electric field concentration phenomenon, and further improving the breakdown voltage and withstand voltage of the HEMT device.

Description

[Technical Field]

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to AlGaN / GaN power HEMT devices and methods for fabricating the same. [Background technology]

[0002] This application claims priority to a Chinese patent application filed with the China Patent Office on December 2, 2021, application number 202111460267.5, entitled "AlGaN / GaN power HEMT device and manufacturing method thereof," the entire contents of which are incorporated herein by reference.

[0003] BACKGROUND ART Power semiconductor devices are widely used in power converters such as DC / DC converters, frequency converters, rectifiers, and inverters, and have excellent power control performance, playing an irreplaceable role in fields such as power systems, photovoltaic power generation systems, and hybrid locomotives.

[0004] Currently, power semiconductor devices often employ device structures such as silicon-based diodes, power MOSFET transistors, and IGBTs (insulated gate bipolar transistors). As power semiconductor devices using Si materials reach their theoretical limits, the generational updates of conventional power semiconductor devices are slowing down. At the current research level, it is difficult for Si-based devices to achieve higher frequencies, higher power densities, and smaller converters.

[0005] Wide-bandgap semiconductor materials, such as gallium nitride (GaN), have characteristics such as a high critical breakdown field, a high saturated electron velocity, a high electron density, a high electron mobility, and a high thermal conductivity, and are semiconductor materials with a high level of radiation resistance that are applicable to high frequencies, high voltages, high temperatures, and high power. GaN devices are the most important semiconductor devices in next-generation radar and communication systems, and are also key devices in new-generation semiconductor lighting. HEMTs (high electron mobility transistors) are heterojunction field-effect transistors. GaN HEMTs are suitable for use as high-frequency switches because they form a two-dimensional electron gas (2DEG) concentration unique to GaN devices through the AlGaN / GaN heterojunction, enabling them to achieve high current densities and high electron saturated drift velocities.

[0006] However, conventional GaN devices still have significant room for improvement in terms of performance, such as breakdown voltage and withstand voltage guarantee. For example, conventional U-type GaN MOS transistors have a field concentration phenomenon at the bottom region of the trench, which limits the improvement of the device's breakdown voltage. How to optimize the channel structure, change the electric field distribution near the trench gate structure, and mitigate the field concentration phenomenon is an issue that needs to be resolved urgently in order to optimize the breakdown characteristics of GaN devices.

[0007] Therefore, there is a need to provide a new AlGaN / GaN power HEMT device and a method for fabricating the same to solve the above problems. Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above-mentioned drawbacks of the prior art, the present invention aims to provide an AlGaN / GaN power HEMT device and a manufacturing method thereof, which solves the problem that the electric field concentration phenomenon exists in the bottom region of the trench in the conventional U-shaped GaN MOS transistor, which limits the improvement of the device breakdown voltage. [Means for solving the problem]

[0009] To achieve the above and other related objects, the present invention provides an AlGaN / GaN power HEMT device, comprising: an n-type GaN substrate; a first p-type GaN layer formed above the n-type GaN substrate; an AlGaN layer formed above the first p-type GaN layer; a hole-injection PN junction layer formed above 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 remaining in the n-type GaN substrate, the gate structure including a gate metal aluminum layer and a gate silicon oxide layer formed on sidewalls and below the gate metal aluminum layer, the hole-injection PN junction layer including a second p-type GaN layer and a second n-type GaN layer distributed along a horizontal direction, the second n-type GaN layer being located closer to the gate structure.

[0010] In one alternative technical solution of the present invention, the thickness of the n-type GaN substrate is in the range of 5 to 10 μm.

[0011] In one alternative technical solution of the present invention, the doping concentration range of the n-type GaN substrate is 1×10 15 ~5×10 15 cm ―3 is.

[0012] In one alternative technical solution of the present invention, the thickness range of the first p-type GaN layer is 0.5 to 1.5 μm.

[0013] In one alternative technical solution of the present invention, the doping concentration range of the first p-type GaN layer is 1×10 16 ~1×10 17 cm ―3 is.

[0014] In one alternative technical solution of the present invention, the thickness range of the AlGaN layer is 0.05 to 0.15 μm.

[0015] In one alternative technical solution of the present invention, the doping concentration range of the AlGaN layer is 2×10 18 ~5×10 18 cm ―3 is.

[0016] As one alternative technical solution of the present invention, the thickness range of the hole injection type PN junction layer is 0.5 to 1.5 μm.

[0017] In one alternative technical solution of the present invention, the doping concentration range of the second p-type GaN layer is 1×10 17 ~1×10 18 cm ―3 is.

[0018] In one alternative technical solution of the present invention, the doping concentration range of the second n-type GaN layer is 1×10 18 ~1×10 19 cm ―3 is.

[0019] In one alternative technical solution of the present invention, the thickness of the gate metal aluminum layer is in the range of 0.5 to 5 μm.

[0020] In one alternative technical solution of the present invention, the thickness range of the gate silicon oxide layer is 0.5 to 5 μm.

[0021] As an alternative technical solution of the present invention, the AlGaN / GaN power HEMT device further includes a first n-type GaN layer formed below the n-type GaN substrate, and the first n-type GaN layer is led out as a drain electrode of the AlGaN / GaN power HEMT device.

[0022] In one alternative technical solution of the present invention, the thickness range of the first n-type GaN layer is 0.5 to 1.5 μm, and the doping concentration range of the first n-type GaN layer is 1×10 18 ~5×10 18 cm ―3 is.

[0023] As an alternative technical solution of the present invention, the AlGaN / GaN power HEMT device further includes a source metal layer formed above the hole injection type PN junction layer. In one alternative technical solution of the present invention, the thickness of the source metal layer is in the range of 0.05 to 0.15 μm.

[0024] In one alternative technical solution of the present invention, the source metal layer includes a metallic gold layer, and the metallic gold layer is led out as a source electrode of the AlGaN / GaN power HEMT device.

[0025] In one alternative technical solution of the present invention, the AlGaN / GaN power HEMT device further includes a metal aluminum layer formed above the hole injection type PN junction layer, the metal aluminum layer and the metal gold layer being distributed along the horizontal direction, and the metal aluminum layer being located closer to the gate structure.

[0026] In one alternative technical solution of the present invention, the thickness of the metal aluminum layer is in the range of 0.05 to 0.15 μm.

[0027] In one alternative technical solution of the present invention, the boundary between the metallic aluminum layer and the metallic gold layer is located above the second n-type GaN layer.

[0028] The present invention further provides a method for manufacturing an AlGaN / GaN power HEMT device, comprising the steps of providing an n-type GaN substrate, forming a first p-type GaN layer, an AlGaN layer, and a hole-injection PN junction layer above the n-type GaN substrate in this order, and forming a gate structure penetrating the hole-injection PN junction layer, the AlGaN layer, and the first p-type GaN layer and remaining in the n-type GaN substrate, the gate structure including a gate metal aluminum layer and a gate silicon oxide layer formed on sidewalls and below the gate metal aluminum layer, the hole-injection PN junction layer including a second p-type GaN layer and a second n-type GaN layer distributed horizontally, the second n-type GaN layer being closer to the gate structure.

[0029] As an alternative technical solution of the present invention, the method for manufacturing the AlGaN / GaN power HEMT device further includes a step of forming a first n-type GaN layer below the n-type GaN substrate, and the first n-type GaN layer is led out as a drain electrode of the AlGaN / GaN power HEMT device.

[0030] As an alternative technical solution of the present invention, the method for manufacturing the AlGaN / GaN power HEMT device further includes forming a source metal layer above the hole injection type PN junction layer.

[0031] In one alternative technical solution of the present invention, the source metal layer includes a metallic gold layer, and the metallic gold layer is led out as a source electrode of the AlGaN / GaN power HEMT device.

[0032] As an alternative technical solution of the present invention, the method for manufacturing the AlGaN / GaN power HEMT device further includes forming a metal aluminum layer above the hole injection type PN junction layer.

[0033] In one alternative technical solution of the present invention, the metal aluminum layer and the metal gold layer are distributed along the horizontal direction, and the metal aluminum layer is located closer to the gate structure.

[0034] In one alternative technical solution of the present invention, the boundary between the metallic aluminum layer and the metallic gold layer is located above the second n-type GaN layer. [Effects of the Invention]

[0035] As described above, the AlGaN / GaN power HEMT device and its manufacturing method provided by the present invention have the following beneficial effects. Compared with conventional U-type GaN MOS transistors, the AlGaN / GaN power HEMT device provided by the present invention introduces a new structural design, and by designing the channel structure vertically, it changes the electric field distribution near the trench gate structure, effectively alleviates the electric field concentration phenomenon, and further improves the breakdown voltage and withstand voltage of the HEMT device. [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a structural schematic diagram of an AlGaN / GaN power HEMT device provided in Example 1 of the present invention. FIG. [Figure 2] FIG. 2 is a breakdown voltage characteristic curve diagram of the AlGaN / GaN power HEMT device provided in Example 1 of the present invention. [Figure 3] FIG. 2 is a transfer characteristic curve diagram of the AlGaN / GaN power HEMT device provided in Example 1 of the present invention. [Figure 4] FIG. 2 is an output characteristic curve diagram of the AlGaN / GaN power HEMT device provided in Example 1 of the present invention. [Figure 5] FIG. 2 is a schematic diagram of an n-type GaN substrate provided in Example 2 of the present invention. [Figure 6]FIG. 10 is a schematic diagram showing a first p-type GaN layer, an AlGaN layer, and a hole injection type PN junction layer formed in this order from bottom to top above an n-type GaN substrate in Example 2 of the present invention. [Figure 7] FIG. 10 is a schematic diagram illustrating the formation of a gate structure in Example 2 of the present invention. [Figure 8] FIG. 10 is a schematic diagram illustrating the formation of a source metal layer and a metal aluminum layer in Example 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] Although the embodiments of the present invention will be described below with reference to specific examples, those skilled in the art will readily understand other advantages and effects of the present invention from the contents disclosed herein. The present invention can also be implemented or applied with other different specific embodiments, and each detail in this specification may be based on different viewpoints and applications, and various modifications or changes can be made without departing from the spirit of the present invention.

[0038] Please refer to Figures 1 to 8. The drawings provided in this embodiment are for explaining the basic concept of the present invention in a schematic form, and only components related to the present invention are shown in the drawings, but are not based on the number, shape, and dimensions of components in actual implementation. When actually implemented, the shape, number, and ratio of each component may be arbitrarily changed, and the component layout may be more complex.

[0039] Example 1 1 to 4, this embodiment provides an AlGaN / GaN power HEMT device, and the AlGaN / GaN power HEMT device includes an n-type GaN substrate 109, a first p-type GaN layer 108 formed above the n-type GaN substrate 109, an AlGaN layer 107 formed above the first p-type GaN layer 108, a hole injection type PN junction layer formed above the AlGaN layer 107, and a hole injection type PN junction layer formed through the hole injection type PN junction layer, the AlGaN layer 107, and the first p-type GaN layer 108. and a gate structure remaining in the n-type GaN substrate 109, the gate structure including a gate metal aluminum layer 102 and a gate silicon oxide layer 101 formed on the sidewalls and below the gate metal aluminum layer 102, the hole injection type PN junction layer including a second p-type GaN layer 105 and a second n-type GaN layer 106 distributed along the horizontal direction, the second n-type GaN layer 106 being located on the side closer to the gate structure, and the gate metal aluminum layer 102 being drawn out as a gate electrode G.

[0040] Compared with conventional U-type GaN MOS transistors, the AlGaN / GaN power HEMT device provided by the present invention introduces a new structural design, designs the channel structure vertically, changes the electric field distribution near the trench gate structure, and effectively alleviates the electric field concentration phenomenon, thereby improving the breakdown voltage and withstand voltage of the HEMT device.

[0041] For example, the thickness range of the n-type GaN substrate 109 is 5 to 10 μm (endpoints included, and in this specification, when a numerical range is described, the end points are included unless otherwise specified), and the doping concentration range is 1×10 15 ~5×10 15 cm ―3 is.

[0042] For example, the thickness of the first p-type GaN layer 108 is in the range of 0.5 to 1.5 μm, and the doping concentration is in the range of 1×10 16 ~1×10 17 cm ―3 is.

[0043] For example, the thickness range of the AlGaN layer 107 is 0.05 to 0.15 μm, and the doping concentration range is 2×10 18 ~5×10 18 cm ―3 is.

[0044] For example, the thickness range of the hole injection type PN junction layer is 0.5 to 1.5 μm, and the doping concentration range of the second p-type GaN layer 105 is 1×10 17 ~1×10 18 cm ―3 and the doping concentration range of the second n-type GaN layer 106 is 1×10 18 ~1×10 19 cm ―3 is.

[0045] For example, the thickness range of the gate metal aluminum layer 102 is 0.5 to 5 μm, and the thickness range of the gate silicon oxide layer 101 is 0.5 to 5 μm.

[0046] For example, as shown in FIG. 1, the AlGaN / GaN power HEMT device further includes a first n-type GaN layer 110 formed below the n-type GaN substrate, and the first n-type GaN layer 110 is connected as a drain electrode D of the AlGaN / GaN power HEMT device.

[0047] For example, as shown in FIG. 1, the thickness range of the first n-type GaN layer 110 is 0.5 to 1.5 μm, and the doping concentration range is 1×10 18 ~5×10 18 cm ―3 is.

[0048] For example, the AlGaN / GaN power HEMT device further includes a source metal layer formed above the hole injection type PN junction layer, as shown in Figure 1. In one preferred example, the thickness of the source metal layer is in the range of 0.05 to 0.15 µm.

[0049] 1, the source metal layer includes a metallic gold layer 104, which is connected as a source electrode S of the AlGaN / GaN power HEMT device. As an example, as shown in FIG. 1, the AlGaN / GaN power HEMT device further includes a metallic aluminum layer 103 formed above the hole injection type PN junction layer, where the metallic aluminum layer 103 and the metallic gold layer 104 are distributed horizontally and the metallic aluminum layer 103 is located closer to the gate structure. In one preferred example, the boundary between the metallic aluminum layer 103 and the metallic gold layer 104 is located above the second n-type GaN layer 106.

[0050] For example, in this embodiment, the thickness of the n-type GaN substrate 109 is 8 μm, and the doping concentration is 2×10 15 cm ―3 Preferably, the thickness of the first p-type GaN layer 108 is 1 μm, and the doping concentration thereof is 5×10 16 cm ―3 The thickness of the AlGaN layer 107 is 0.1 μm, and the doping concentration is 2×10 18 cm ―3 The thickness of the hole injection type PN junction layer is 1 μm, that is, the thickness of the second p-type GaN layer 105 and the second n-type GaN layer 106 are both 1 μm, and the doping concentration of the second p-type GaN layer 105 is 4×10 17 cm ―3 and the doping concentration of the second n-type GaN layer 106 is 2×10 18 cm ―3 The thickness of the gate metal aluminum layer 102 is 2.2 μm, and the thickness of the gate silicon oxide layer 101 is 2.3 μm. The thickness of the first n-type GaN layer 110 is 1 μm, and the doping concentration thereof is 2×10 18 cm ―3 The thickness of the source metal layer is 0.1 μm, that is, the thickness of the metallic gold layer 104 is 0.1 μm, and the thickness of the metallic aluminum layer 103 is 0.1 μm.

[0051] The AlGaN / GaN power HEMT device provided in this embodiment is a reinforced GaN transistor, and its maximum withstand voltage can reach 860V. As shown in Figure 1, the AlGaN / GaN power HEMT device has a vertical structure. Specifically, the first n-type GaN layer 110 is used as the substrate, and the n-type GaN substrate 109 is used as the transition layer and drift region, both of which are 8 μm thick. The first p-type GaN layer 108 and the AlGaN layer 107 are epitaxially grown on the n-type GaN substrate 109. The formed AlGaN / GaN heterojunction can generate a conductive two-dimensional electron gas (2DEG), thereby improving the electron transport rate, effectively increasing the device breakdown voltage, and further improving the device output 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, and includes a gate metal aluminum layer 102 and a gate silicon oxide layer 101 formed on the sidewalls and below the gate metal aluminum layer 102. The trench width of the trench gate is 2 μm, and the trench thickness is 2.3 μm.

[0052] In conventional U-shaped GaN MOS transistors, the electric field concentration phenomenon at the bottom region of the trench limits the improvement of the breakdown voltage of the device. However, the channel structure of the AlGaN / GaN power HEMT device in this embodiment is a vertical structure, and a structure is designed for a thick drift region. In addition, two-dimensional electron gas is used, and the drift region is further optimized to change the electric field distribution near the trench gate structure, thereby alleviating the electric field concentration phenomenon, and further improving the breakdown characteristics of the U-shaped AlGaN / GaN power HEMT device and increasing the figure of merit of the device.

[0053] Figure 2 shows the breakdown voltage characteristic curve of the AlGaN / GaN power HEMT device provided by this example. As a type of power device, the AlGaN / GaN power HEMT device must be able to withstand high voltages in the off state. This ability can be evaluated by the breakdown voltage. For AlGaN / GaN power HEMT devices, the device leakage current is usually 50 mA / cm. 2 The drain electrode voltage corresponding to a voltage higher than 1 V is called the breakdown voltage. As shown in Figure 2, in this example, the breakdown voltage value of the AlGaN / GaN power HEMT device reaches 860 V, which is far higher than the breakdown voltage of 400 V of a conventional U-type GaN MOS transistor. Note that when the breakdown voltage value is 860 V, the device is not damaged and the withstand voltage curve is repeatable.

[0054] FIG. 3 is a transfer characteristic curve diagram of the AlGaN / GaN power HEMT device provided in this embodiment. The transfer characteristic of the device shows the relationship between the drain electrode current ID and the gate electrode voltage VGS at a fixed drain electrode voltage VDS, and can reflect the amplification capability of the device. FIG. 3 is a transfer curve in linear coordinates of the AlGaN / GaN power HEMT device in this embodiment, where the drain electrode voltage VDS=1V. From the transfer characteristic curve in FIG. 3, the threshold voltage VTH, saturation current, on-off ratio I ON / I OFF Important parameters such as the subthreshold swing S and threshold voltage V are obtained, with the threshold voltage V being 7.5 V and the saturation current being 0.1 A, 0.05 A, and 0.01 A. As can be seen, each of the above parameters is also superior to that of the conventional U-type GaN MOS transistor.

[0055] Figure 4 shows the output characteristic curves of the AlGaN / GaN power HEMT device provided in this example. The output characteristic curve can be understood as the drain electrode voltammetry characteristics, i.e., the relationship between the drain electrode current (ID) and the drain electrode voltage (VDS). As shown in Figure 4, the output characteristic curves are divided into linear, nonlinear, and saturation regions. By converting the gate electrode voltage, a series of output curves can be obtained, and parameters such as the device on-resistance (RON) can be extracted. In Figure 4, GaN_1, GaN_2, and GaN_3 are output curves at different saturation currents (0.1, 0.05, and 0.01 A) obtained by converting different gate electrode voltages (8, 9, and 10 V).

[0056] The AlGaN / GaN power HEMT device provided in this embodiment allows for a small variable range of gate-source voltages and a small maximum on-resistance, forming a low thermal resistance, making it suitable for high-temperature environments. When the gate-source voltage is 0, the transistor is in reverse conduction, and the forward voltage drop across the source-drain electrodes of the AlGaN / GaN power HEMT device is larger than that of a silicon-based MOSFET transistor. In LCC resonant converter applications, the AlGaN / GaN power HEMT device has lower losses than a silicon-based MOSFET transistor.

[0057] Example 2 5 to 8, this embodiment provides a method for manufacturing an AlGaN / GaN power HEMT device, which includes the following steps: 1) An n-type GaN substrate 109 is provided. 2) Above the n-type GaN substrate 109, a first p-type GaN layer 108, an AlGaN layer 107, and a hole injection type PN junction layer 111 are formed in this order from bottom to top. 3) A gate structure 112 is formed so as to penetrate the hole injection type PN junction layer 111, the AlGaN layer 107, and the first p-type GaN layer 108 and remain in the n-type GaN substrate 109, the gate structure 112 including a gate metal aluminum layer 102 and a gate silicon oxide layer 101 formed on the sidewalls and below the gate metal aluminum layer 102, the hole injection type PN junction layer 111 including a second p-type GaN layer 105 and a second n-type GaN layer 106 distributed along the horizontal direction, the second n-type GaN layer 106 being located closer to the gate structure 112.

[0058] In step 1), an n-type GaN substrate 109 is provided, as shown in Fig. 5. In a preferred example, a first n-type GaN layer 110 is further formed below the n-type GaN substrate 109, and the first n-type GaN layer 110 is extracted as a drain electrode 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 epitaxially growing them in sequence on an epitaxial substrate.

[0059] In step 2), as shown in FIG. 6, a first p-type GaN layer 108, an AlGaN layer 107, and a hole-injection PN junction layer 111 are formed on the n-type GaN substrate 109 in this order. The hole-injection PN junction layer 111 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 closer to a gate structure 112 to be formed later. The method for forming the first p-type GaN layer 108, the AlGaN layer 107, and the hole-injection PN junction layer 111 includes epitaxially growing the necessary material layers and then achieving the necessary doping concentrations by diffusion or ion implantation. The boundaries of the second p-type GaN layer 105 and the second n-type GaN layer 106 can be defined by photolithography, and oppositely doped GaN layers can be obtained by ion implanting the p-type GaN layer or the n-type GaN layer.

[0060] In step 3), as shown in FIG. 7 , a gate structure 112 is formed penetrating the hole injection type PN junction layer 111, the AlGaN layer 107, and the first p-type GaN layer 108 and remaining in the n-type GaN substrate 109, and the gate structure 112 includes a gate metal aluminum layer 102 and a gate silicon oxide layer 101 formed on the sidewalls and below the gate metal aluminum layer 102.

[0061] For example, as shown in FIG. 8 , the method for manufacturing the AlGaN / GaN power HEMT device further includes a step of forming a source metal layer 113 above the hole injection type PN junction layer 111. In a preferred example, the source metal layer 113 is a metallic gold layer 104, which is connected to a source electrode S of the AlGaN / GaN power HEMT device. For example, as shown in FIG. 8 , the method for manufacturing the AlGaN / GaN power HEMT device further includes a step of forming a metallic aluminum layer 103 above the hole injection type PN junction layer 111, where the metallic gold layer 104 and the metallic aluminum layer 103 are distributed horizontally and the metallic aluminum layer 103 is located closer to the gate structure 112. The boundary between the metallic aluminum layer 103 and the metallic gold layer 104 is located above the second n-type GaN layer 106. The process for forming the source metal layer 113 includes, but is not limited to, a PVD process.

[0062] In a preferred example, in this embodiment, the thickness of the n-type GaN substrate 109 is 8 μm, and the doping concentration is 2×10 15 cm ―3 Preferably, the thickness of the first p-type GaN layer 108 is 1 μm, and the doping concentration thereof is 5×10 16 cm ―3 The thickness of the AlGaN layer 107 is 0.1 μm, and the doping concentration is 2×10 18 cm ―3The hole injection type PN junction layer 111 has a thickness of 1 μm, that is, the second p-type GaN layer 105 and the second n-type GaN layer 106 each have a thickness of 1 μm, and the doping concentration of the second p-type GaN layer 105 is 4×10 17 cm ―3 and the doping concentration of the second n-type GaN layer 106 is 2×10 18 cm ―3 The thickness of the gate metal aluminum layer 102 is 2.2 μm, and the thickness of the gate silicon oxide layer 101 is 2.3 μm. The thickness of the first n-type GaN layer 110 is 1 μm, and the doping concentration thereof is 2×10 18 cm ―3 The thickness of the source metal layer 113 is 0.1 μm, i.e., the thickness of the metal gold layer 104 is 0.1 μm. The thickness of the metal aluminum layer 103 is 0.1 μm. The AlGaN / GaN power HEMT device employing the above design optimizes the drift region, changes the electric field distribution near the trench gate structure, alleviates the electric field concentration phenomenon, and further improves the device breakdown characteristics and device figure of merit.

[0063] As described above, the present invention provides an AlGaN / GaN power HEMT device and a manufacturing method thereof, the AlGaN / GaN power HEMT device including an n-type GaN substrate, a first p-type GaN layer formed above the n-type GaN substrate, an AlGaN layer formed above the first p-type GaN layer, a hole-injection PN junction layer formed above 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 remaining in the n-type GaN substrate, the gate structure including a gate metal aluminum layer and a gate silicon oxide layer formed on sidewalls and below the gate metal aluminum layer, the hole-injection PN junction layer including a second p-type GaN layer and a second n-type GaN layer distributed along a horizontal direction, the second n-type GaN layer being located closer to the gate structure. Compared with the conventional U-type GaN MOS transistor, the AlGaN / GaN power HEMT device provided by the present invention introduces a new structural design, and the channel structure is designed vertically, which changes the electric field distribution near the trench gate structure, improves the electric field concentration phenomenon, and further improves the breakdown voltage and withstand voltage of the HEMT device.

[0064] The above examples are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Those skilled in the art may modify or change the above-described embodiments without departing from the spirit and scope of the present invention. Therefore, equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be included in the scope of the claims of the present invention. [Explanation of symbols]

[0065] 101 gate oxide silicon layer, 102 gate metal aluminum layer, 103 metal aluminum layer, 104 metal gold layer, 105 second p-type GaN layer, 106 second n-type GaN layer, 107 AlGaN layer, 108 first p-type GaN layer, 109 n-type GaN substrate, 110 first n-type GaN layer, 111 hole injection type PN junction layer, 112 gate structure, 113 source metal layer, G gate electrode, S source electrode, D drain electrode.

Claims

1. 1. An AlGaN / GaN power HEMT device, comprising: an n-type GaN substrate; a first p-type GaN layer formed above the n-type GaN substrate; an AlGaN layer formed above the first p-type GaN layer; a hole injection type PN junction layer formed above the AlGaN layer; a gate structure penetrating the hole injection type PN junction layer, the AlGaN layer, and the first p-type GaN layer and remaining in the n-type GaN substrate; a source metal layer formed above the hole injection type PN junction layer, the gate structure includes a gate metal aluminum layer and a gate silicon oxide layer formed on sidewalls and below the gate metal aluminum layer, the hole injection type PN junction layer includes a second p-type GaN layer and a second n-type GaN layer distributed along a horizontal direction, and the second n-type GaN layer is located on a side closer to the gate structure.

2. The thickness range of the n-type GaN substrate is 5 to 10 μm, and the doping concentration range of the n-type GaN substrate is 1×10 １５ ~5 x 10 １５ cm ―３ The thickness range of the first p-type GaN layer is 0.5 to 1.5 μm, and the doping concentration range of the first p-type GaN layer is 1×10 １６ ~1 x 10 １７ cm ―３ The thickness range of the AlGaN layer is 0.05 to 0.15 μm, and the doping concentration range of the AlGaN layer is 2×10 １８ ~5 x 10 １８ cm ―３ The thickness range of the hole injection type PN junction layer is 0.5 to 1.5 μm, and the doping concentration range of the second p-type GaN layer is 1×10 １７ ~1 x 10 １８ cm ―３ and the doping concentration range of the second n-type GaN layer is 1×10 １８ ~1 x 10 １９ cm ―３ 2. The AlGaN / GaN power HEMT device of claim 1, wherein the thickness range of the gate metal aluminum layer is 0.5 to 5 μm, and the thickness range of the gate silicon oxide layer is 0.5 to 5 μm.

3. The thickness of the n-type GaN substrate is 8 μm, and the doping concentration of the n-type GaN substrate is 2×10 １５ cm ―３ The thickness of the first p-type GaN layer is 1 μm, and the doping concentration of the first p-type GaN layer is 5×10 １６ cm ―３ The thickness of the AlGaN layer is 0.1 μm, and the doping concentration of the AlGaN layer is 2×10 １８ cm ―３ the hole injection type PN junction layer has a thickness of 1 μm, the second p-type GaN layer and the second n-type GaN layer have a thickness of 1 μm, and the doping concentration of the second p-type GaN layer is 4×10 １７ cm ―３ and the doping concentration of the second n-type GaN layer is 2×10 １８ cm ―３ 3. The AlGaN / GaN power HEMT device of claim 2, wherein the thickness of the gate metal aluminum layer is 2.2 μm and the thickness of the gate silicon oxide layer is 2.3 μm.

4. 2. The AlGaN / GaN power HEMT device according to claim 1, further comprising a first n-type GaN layer formed below the n-type GaN substrate, the first n-type GaN layer being led out as a drain electrode of the AlGaN / GaN power HEMT device.

5. The thickness range of the first n-type GaN layer is 0.5 to 1.5 μm, and the doping concentration range of the first n-type GaN layer is 1×10 １８ ~5 x 10 １８ cm ―３ 5. The AlGaN / GaN power HEMT device of claim 4, wherein:

6. The thickness of the first n-type GaN layer is 1 μm, and the doping concentration of the first n-type GaN layer is 2×10 １８ cm ―３ 6. The AlGaN / GaN power HEMT device of claim 5, wherein:

7. 2. The AlGaN / GaN power HEMT device of claim 1, wherein the thickness range of the source metal layer is 0.05 to 0.15 μm.

8. 2. The AlGaN / GaN power HEMT device according to claim 1, wherein the source metal layer comprises a metallic gold layer, the metallic gold layer being extracted as a source electrode of the AlGaN / GaN power HEMT device, the AlGaN / GaN power HEMT device further comprising a metallic aluminum layer formed above the hole injection type PN junction layer, the metallic aluminum layer and the metallic gold layer being distributed along a horizontal direction, and the metallic aluminum layer being located on a side closer to the gate structure.

9. 9. The AlGaN / GaN power HEMT device according to claim 8, wherein the thickness of the metallic aluminum layer and the metallic gold layer is both 0.1 μm.

10. 9. The AlGaN / GaN power HEMT device according to claim 8, wherein the boundary between the metallic aluminum layer and the metallic gold layer is located above the second n-type GaN layer.

11. 1. A method for manufacturing an AlGaN / GaN power HEMT device, comprising: providing an n-type GaN substrate; forming a first p-type GaN layer, an AlGaN layer, and a hole injection type PN junction layer in this order above the n-type GaN substrate; forming a gate structure that penetrates the hole-injection type PN junction layer, the AlGaN layer, and the first p-type GaN layer and remains in the n-type GaN substrate; forming a source metal layer above the hole injection type PN junction layer; the gate structure includes a gate metal aluminum layer and a gate silicon oxide layer formed on sidewalls and below the gate metal aluminum layer, the hole injection type PN junction layer includes a second p-type GaN layer and a second n-type GaN layer distributed in a horizontal direction, and the second n-type GaN layer is located closer to the gate structure.

12. 12. The method for manufacturing an AlGaN / GaN power HEMT device according to claim 11, further comprising the step of forming a first n-type GaN layer below the n-type GaN substrate, the first n-type GaN layer being led out as a drain electrode of the AlGaN / GaN power HEMT device.

13. The method for manufacturing an AlGaN / GaN power HEMT device described in claim 11, characterized in that the source metal layer includes a metallic gold layer, and the metallic gold layer is extracted as a source electrode of the AlGaN / GaN power HEMT device, and the method for manufacturing the AlGaN / GaN power HEMT device further includes a step of forming a metallic aluminum layer above the hole injection type PN junction layer, the metallic aluminum layer and the metallic gold layer being distributed along the horizontal direction, and the metallic aluminum layer being located on the side closer to the gate structure.

14. 14. The method for manufacturing an AlGaN / GaN power HEMT device according to claim 13, wherein a boundary between the metallic aluminum layer and the metallic gold layer is located above the second n-type GaN layer.

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