This application claims priority to Chinese Patent Application No. 202111460267.5, filed in the Chinese Patent Office on Dec. 2, 2021, entitled “AlGaN/GaN POWER HEMT DEVICE AND METHOD FOR MANUFACTURING THE SAME”, which is incorporated herein by reference in its entirety.
The present disclosure relates to a field of semiconductor devices, and more particularly, to an AlGaN/GaN power HEMT device and a method for manufacturing the same.
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, hybrid locomotives, and the like.
Currently, most power semiconductor devices have a structure such as a silicon-based diode, a power MOSFET transistor, and an Insulated Gate Bipolar Transistor (IGBT). As power semiconductor devices using Si materials gradually reach their theoretical limits, the speed of renewal of existing power semiconductor devices continues to slow down. At the present research level, it is difficult to further realize high frequency, high power density and miniaturization of the Si-based device.
A wide-band-gap semiconductor material represented by gallium nitride (GaN) has characteristics of high critical breakdown electric field, high saturated electron velocity, high electron density, high electron mobility, high thermal conductivity, and the like, and is a high-radiation-resistant semiconductor material suitable for high frequency, high voltage, high temperature, and high power. GaN devices are the most critical semiconductor devices in the new generation of radar and communication systems, and are also the main devices in the new generation of semiconductor lighting. High Electron Mobility Transistor (HEMT) is a heterojunction field effect transistor. The GaN HEMT has a two-dimensional electron gas (2DEG) concentration characteristic of the GaN device formed by the AlGaN/GaN heterojunction, so that a high current density and a high electron saturation drift speed can be achieved. Therefore, the GaN HEMT is suitable as a high-frequency switch.
However, conventional GaN devices still have a large space for improvement in performance such as breakdown voltage and withstand voltage. For example, the conventional U-shaped GaN MOS transistor has an electric field concentration phenomenon in the region of the bottom of the trench, which limits an increase in the breakdown voltage of the device. How to optimize the channel structure, change the electric field distribution near the trench gate structure, and alleviate the electric field concentration phenomenon is an urgent problem to be solved for optimizing the breakdown characteristics of GaN devices.
Therefore, it is necessary to propose a new AlGaN/GaN power HEMT device and a method of manufacturing the same to solve the above problems.
In view of the above-described disadvantages of the prior art, it is an object of the present disclosure to provide an AlGaN/GaN power HEMT device and a method for manufacturing the same, for solving the problems in the prior art that a conventional U-shaped GaN MOS transistor has an electric field concentration phenomenon in a bottom region of a trench, which restricts an improvement a breakdown voltage of the device.
To achieve the above and other related objects, the present disclosure provides an AlGaN/GaN power HEMT device including:
As an alternative solution of the present disclosure, the n-type GaN substrate has a thickness in a range of 5-10 μm.
As an alternative solution of the present disclosure, a doping concentration the n-type GaN substrate is in a range of 1×1015-5×1015 cm−3.
As an alternative solution of the present disclosure, the first p-type GaN layer has a thickness in a range of 0.5-1.5 μm.
As an alternative solution of the present disclosure, a doping concentration of the first p-type GaN layer is in a range of 1×1016-1λ1017 cm−3.
As an alternative solution of the present disclosure, the AlGaN layer has a thickness in a range of 0.05-0.15 μm.
As an alternative solution of the present disclosure, a doping concentration of the AlGaN layer is in a range of 2×1018-5×1018 cm−3.
As an alternative solution of the present disclosure, the hole-injection type PN junction layer has a thickness in a range of 0.5-1.5 μm.
As an alternative solution of the present disclosure, a doping concentration of the second p-type GaN layer is in a range of 1×1017-1×1018 cm−3.
As an alternative solution of the present disclosure, a doping concentration of the second n-type GaN layer is in a range of 1×1018-1×1019 cm−3.
As an alternative solution of the present disclosure, the gate metal aluminum layer has a thickness in a range of 0.5-5 μm.
As an alternative solution of the present disclosure, the gate silicon dioxide layer has a thickness in the range of 0.5-5 μm.
As an alternative solution of the present disclosure, 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 of the AlGaN/GaN power HEMT device.
As an alternative solution of the present disclosure, the first n-type GaN layer has a thickness in a range of 0.5-1.5 μm and a doping concentration of the first n-type GaN layer is in a range of 1×1018-5×1018 cm−3.
As an alternative solution of the present disclosure, the AlGaN/GaN power HEMT device further includes a source metal layer formed above the hole-injection type PN junction layer.
As an alternative solution of the present disclosure, the source metal layer has a thickness in a range of 0.05-0.15 μm.
As an alternative solution of the present disclosure, the source metal layer comprises a metal gold layer, and the metal gold layer is led out as a source of the AlGaN/GaN power HEMT device.
As an alternative solution of the present disclosure, 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 are distributed in a horizontal direction, and the metal aluminum layer is located at a side close to the gate structure.
As an alternative solution of the present disclosure, the metal aluminum layer has a thickness in a range of 0.05-0.15 μm.
As an alternative solution of the present disclosure, an interface between the metal aluminum layer and the metal gold layer is located above the second n-type GaN layer.
The present disclosure further provides a method for manufacturing an AlGaN/GaN power HEMT device, including the steps of:
As an alternative solution of the present disclosure, the method for manufacturing the AlGaN/GaN power HEMT device further includes 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 of the AlGaN/GaN-power HEMT device.
As an alternative solution of the present disclosure, the source metal layer includes a metal gold layer, the metal gold layer is led out as a source of the AlGaN/GaN power HEMT device.
As an alternative solution of the present disclosure, the method for manufacturing the AlGaN/GaN power HEMT device further includes the step of forming a metal aluminum layer above the hole-injection type PN junction layer.
As an alternative solution of the present disclosure, the metal aluminum layer and the metal gold layer are distributed in a horizontal direction, and the metal aluminum layer is located at a side close to the gate structure.
As an alternative solution of the present disclosure, an interface between the metal aluminum layer and the metal gold layer is located above the second n-type GaN layer.
As described above, the AlGaN/GaN power HEMT device provided by the present disclosure and the method for manufacturing the same have the following beneficial effects:
Further advantages and advantages of the present disclosure will become readily apparent to those skilled in the art from the disclosure of this specification, which is illustrated by specific examples. The disclosure may also be practiced or applied by other different embodiments, and various modifications or changes may be made in the details of the specification without departing from the spirit of the disclosure, based on different points of view and applications.
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The hole-injection type 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 at a side close to the gate structure, and the gate metal aluminum layer 102 is led out as a gate G.
Compared with a conventional U-type GaN MOS transistor, the AlGaN/GaN power HEMT device provided by the present disclosure introduces a novel structure design, in which a channel structure is designed in a longitudinal direction to change an electric field distribution in the vicinity of a trench gate structure, thereby effectively relieving electric field concentration phenomenon, and further improving breakdown voltage and withstand voltage of the HEMT device.
As an example, the n-type GaN substrate 109 has a thickness in the range of 5 μm-10 μm (including the point value; in the description of the present disclosure, when referring to numerical ranges, unless otherwise specified, the point values are included), and a doping concentration thereof is in a range of 1×1015 cm−3-5×1015 cm−3.
As an example, the first p-type GaN layer 108 has a thickness in a range of 0.5 μm-1.5 μm and a doping concentration thereof is in a range of 1×1016-1×1017 cm−3.
As an example, the AlGaN layer 107 has a thickness in the range of 0.05 μm-0.15 μm and a doping concentration thereof is in the range of 2×1018-5×1018 cm−3.
As an example, the hole-injection type PN junction layer has a thickness in the range of 0.5 μm-1.5 μm, a doping concentration of the second p-type GaN layer 105 is in a range of 1×1017-1×1018 cm−3, and a doping concentration of the second n-type GaN layer 106 is in a range of 1×1018-1×1019 cm−3.
As an example, the gate metal aluminum layer 102 has a thickness in a range of 0.5 μm-5 μm, and the gate silicon dioxide layer 101 has a thickness in a range of 0.5 μm-5 μm.
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As an example, in the present embodiment, the n-type GaN substrate 109 has a thickness of 8 μm and a doping concentration thereof is 2×1015 cm−3. Preferably, the first p-type GaN layer 108 has a thickness of 1 μm and a doping concentration thereof is 5×1016 cm−3. The AlGaN layer 107 has a thickness of 0.1 μm and a doping concentration thereof is 2×1018 cm−3. The hole-injection type PN junction layer has a thickness of 1 μm, that is, both the second p-type GaN layer 105 and the second n-type GaN layer 106 have the thickness of 1 μm. The doping concentration of the second p-type GaN layer 105 is 4×1018 cm−3, and the doping concentration of the second n-type GaN layer 106 is 2×1018 cm−3. The gate metal 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 thereof is 2×1018 cm−3. The source metal layer has a thickness of 0.1 μm, that is, the metal gold layer 104 has a thickness of 0.1 μm. The metal aluminum layer 103 has a thickness of 0.1 μm.
The AlGaN/GaN power HEMT device provided in this embodiment is an enhanced GaN transistor having a maximum withstand voltage of up to 860 V. As shown in
In the conventional U-shaped GaN MOS transistor, there is an electric field concentration phenomenon in the bottom region of the trench, which restricts the improvement of the breakdown voltage of the device. However, the channel structure of the AlGaN/GaN power HEMT device in the present embodiment is a longitudinal structure, a structure of thick drift region is designed, and a two-dimensional electron gas is used to optimize the drift region, thereby changing the electric field distribution in the vicinity of the trench gate structure, alleviating the electric field concentration phenomenon, improving the breakdown characteristic of the U-shaped AlGaN/GaN power HEMT device, and improving an optimal value of the device.
The gate-source voltage of the AlGaN/GaN power HEMT device provided in the present embodiment is allowed to vary in a small range and has a low maximum on-resistance, forming a low thermal resistance, and therefore, is suitable for a high-temperature environment. When the gate-source voltage is 0 and the transistor is turned on in the reverse direction, the forward source-drain voltage drop of the AlGaN/GaN power HEMT device is larger than that of the silicon-based MOSFET transistor. In applications of LCC resonant converters, the AlGaN/GaN power HEMT device have lower transistor loss than the silicon-based MOSFET transistor.
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In a preferred example, in the present embodiment, the n-type GaN substrate 109 has a thickness of 8 μm and a doping concentration thereof is 2×1015 cm−3. The first p-type GaN layer 108 preferably has a thickness of 1 μm and a doping concentration thereof is 5×1016 cm−3. The AlGaN layer 107 has a thickness of 0.1 μm and a doping concentration thereof is 2×1018 cm−3. The hole-injection type PN junction layer 11 has a thickness 1 μm, that is, both the second p-type GaN layer 105 and the second n-type GaN layer 106 have a thickness of 1 μm. The doping concentration of the second p-type GaN layer 105 is 4×1017 cm−3, and the doping concentration of the second n-type GaN layer 106 is 2×1018 cm−3. The gate metal 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 thereof is 2×1018 cm−3. The thickness of the source metal layer 113 is 0.1 μm, that is, the metal gold layer 104 has a thickness of 0.1 μm. The metal aluminum layer 103 has a thickness of 0.1 μm. The AlGaN/GaN power HEMT device designed as described above can optimize the drift region, change the electric field distribution in the vicinity of the trench gate structure, alleviate the electric field concentration phenomenon, improve the breakdown characteristic of the device, and improve an optimal value of the device.
In view of the foregoing, the present disclosure provides an AlGaN/GaN power HEMT device and a method for manufacturing the same. The AlGaN/GaN power HEMT device includes 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 passing through the hole-injection type PN junction layer, the AlGaN layer, and the first p-type GaN layer, and stopped in the n-type GaN substrate, the gate structure including a gate metal aluminum layer and a gate silicon dioxide layer formed on sidewalls of 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. The second n-type GaN layer is located at a side close to the gate structure, and the gate metal aluminum layer 102 is led out as a gate. Compared with a conventional U-type GaN MOS transistor, the AlGaN/GaN power HEMT device provided by the present disclosure introduces a novel structure design, in which a channel structure is designed in a longitudinal direction to change an electric field distribution in the vicinity of a trench gate structure, thereby effectively relieving electric field concentration phenomenon, and further improving breakdown voltage and withstand voltage of the HEMT device.
The above examples merely illustrate the principles of the disclosure and its efficacy, and are not intended to limit the disclosure. Any person skilled in the art may modify or alter the above-described embodiments without departing from the spirit and scope of the present disclosure. Accordingly, it is intended that all equivalent modifications or changes which persons skill in the art, without departing from the spirit and technical spirit of the disclosure, will achieve will be encompassed by the appended claims.
Number | Date | Country | Kind |
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202111460267.5 | Dec 2021 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2022/136274 | 12/2/2022 | WO |