Sic MOSFET device and preparation method of a kind of slope channel

Abstract

The present application discloses a SiC MOSFET device with a slanted channel. The original cell structure of the active region of the SiC MOSFET device is sequentially drain, n++ substrate, n-drift layer, and two symmetrically arranged p- well layer, p++ area and n++ area, source electrode; the opposite side of the p-well layer is in an upwardly inclined arc shape, and the top of the arc-shaped part of the p-well layer is provided with a vertical center axis inclined to the original cell structure. The secondary epitaxial p-type layer, the implanted n layer is arranged in the middle of the two secondary epitaxial p-type layers, and the "arched" gate oxide layer and polysilicon layer are arranged in sequence above the secondary epitaxial p-type layer and the implanted n layer and isolation passivation layer. This application proposes a SiC MOSFET device with sloped channel, and provides a manufacturing method. In this application, the crystal plane with high electron mobility is used as the channel plane, and the channel is formed on the surface of high-quality secondary epitaxial SiC, which can effectively improve the quality and channel mobility of the MOS gate, and reduce the on-resistance of the device.

Description

technical field [0001] The invention belongs to the field of semiconductors, and in particular relates to a SiC MOSFET device with a slope channel and a preparation method thereof. Background technique [0002] After years of research in the industry for planar SiC MOSFETs, some manufacturers have taken the lead in launching commercial products. However, there are still problems such as low MOS channel mobility and difficult control of product threshold voltage consistency. This is due to the structure and process of the conventional SiC planar MOSFET. The p-well (p-well) in the conventional MOSFET is doped with p-type by ion implantation. This is a general method in the industry. The structure is as follows: figure 1 shown. This method of high-temperature activation annealing after implantation to form doping inevitably has some problems. The first is that the defects caused by implantation cannot be completely eliminated or repaired, and the second is that the high-temp...

AI Technical Summary

Problems solved by technology

The V-shaped groove of the VMOSFET structure is formed by the inconsistent corrosion rate of each crystal plane caused by the anisotropy of SiC under high temperature corrosion, and there is a problem that the process is difficult to control

At the same time, the sharp corners at the bottom of the groove are also likely to cause electric field concentration, resulting in poor reliability

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