AlGaN/GaN heterojunction vertical type field effect transistor with P type shielding layer and manufacturing method of field effect transistor

Abstract

The invention provides an AlGaN / GaN heterojunction vertical type field effect transistor with a P type shielding layer and a manufacturing method of the field effect transistor. The device is mainly characterized in that the P type shielding layer is adopted, and meanwhile, a current low-resistance conducting channel is formed by virtue of the two-dimensional electron gas and a special drift region of the AlGaN / GaN heterojunction. Due to the effect of the P type shielding layer, the concentration of the channel can be reduced to obtain a proper threshold voltage. When the device is switched off, the P type shielding layer effectively reduces the peak electric field in a gate dielectric layer, and the reliability of the device is improved; the two-dimensional electron gas introduces new charges, so that the electric field distribution in the device is changed, the breakdown voltage is improved, and meanwhile, the contradiction between the breakdown voltage and the drift region concentration is weakened. When the device is conducted, the current distribution of the traditional vertical type field effect transistor is changed due to the new conductive channel, so that the relatively low on resistance can be realized under the condition that the concentration of the drift region is relatively low.

Description

technical field [0001] The invention relates to the field of power semiconductor devices, in particular to an AlGaN / GaN heterojunction vertical field effect transistor with a P-type shielding layer. Background technique [0002] As one of the cores of the third-generation semiconductor materials, gallium nitride is special in that it has a polarization effect compared with Si and silicon carbide (SiC). The AlGaN / GaN heterojunction forms a high-density two-dimensional electron gas (two dimensional electron gas, 2DEG) at the heterojunction interface through spontaneous polarization and piezoelectric polarization effects. The high mobility in the channel leads to the low on-resistance of AlGaN / GaN HEMTs. However, the Schottky gate AlGaN / GaN HEMT device has a large reverse leakage, which leads to the deterioration of key performances such as breakdown voltage, efficiency, and gain of the device. [0003] In wide bandgap semiconductors, the impurity diffusion rate is very low, ...

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Problems solved by technology

In addition, when the device is turned off, due to the high voltage, a high electric field will be generated in the gate dielectric layer, which will easily cause the oxide layer to break or even break down, and the life and reliability of the device will also be greatly reduced.

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