Algan/gan heterojunction vertical field effect transistor with p-type shielding layer and manufacturing method thereof

Abstract

The present invention proposes an AlGaN / GaN heterojunction vertical field effect transistor with a P-type shielding layer and a manufacturing method thereof. The two-dimensional electron gas and the special drift region form a low-resistance conduction channel for electric current. Due to the effect of the P-type shielding layer, the concentration of the channel can be reduced to obtain a suitable threshold voltage. When the device is turned off, the P-type shielding layer effectively reduces the peak electric field in the gate dielectric layer and improves the reliability of the device. The two-dimensional electron gas introduces new charges, changes the electric field distribution in the device, and improves the breakdown voltage. , while weakening the contradictory relationship between breakdown voltage and drift region concentration. When the device is turned on, since the new conductive channel changes the current distribution of the traditional vertical field effect transistor, a lower on-resistance can be achieved even when the concentration of the drift region is lower.

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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