Cellular structure of silicon carbide MOSFET device, preparation method of structure and silicon carbide MOSFET device

Abstract

The invention provides a cellular structure of a silicon carbide MOSFET device, a preparation method of the cellular structure and the silicon carbide MOSFET device. The cellular structure comprises afirst conductive type drift layer located above a substrate; side grooves are downwards formed in the positions, at the two sides of the cellular structure, of the surface of the drifting layer, so that a boss is formed in the center of the cellular structure, of the surface of the drifting layer; a second conductive type well region is positioned under the side grooves; a first conductive type source region is positioned in the surface of the well region; and a second conductive type shielding region is arranged in the drift layer and is positioned under the top and the side wall of the bossand the side, close to the boss, of the bottom of the side groove. Due to additional arrangement of the shielding region, the electric field stress of the gate oxide layer of the device in a blockingstate can be greatly reduced, and the reliability of long-term use is greatly improved. The shielding region has little influence on the conduction characteristic of the device, so that a good compromise relationship between the electric field stress of the gate oxide layer and the conduction resistance can be realized.

Description

technical field [0001] The present disclosure relates to the technical field of semiconductor devices, in particular to a cell structure of a silicon carbide MOSFET device, a preparation method thereof, and a silicon carbide MOSFET device. Background technique [0002] Silicon carbide (SiC) is a new wide-bandgap semiconductor material with excellent physical, chemical and electrical properties. The breakdown electric field strength of silicon carbide is 10 times that of traditional silicon, the thermal conductivity is 3 times that of silicon, and it has a higher switching frequency, which can reduce the loss and volume of energy storage components in the circuit. Theoretically, SiC devices can work in a high-temperature environment above 600°C, and have excellent radiation resistance, which greatly improves their high-temperature stability. This makes SiC-based power semiconductor devices very attractive and promising for high-power and high-temperature applications. Among...

AI Technical Summary

Problems solved by technology

[0004] In view of the above problems, the present disclosure provides a cell structure of a silicon carbide MOSFET device, its preparation method and a silicon carbide MOSFET device, which solves the problem of the electric field stress and device failure of silicon carbide MOSFETs in the prior art that cannot achieve a good gate oxide layer. The technical issue of the trade-off relationship between on-resistance

Images