Silicon carbide groove-shaped metal-oxide-semiconductor field-effect transistors (MOSFETs) and fabrication method thereof

Abstract

The invention provides silicon carbide groove-shaped metal-oxide-semiconductor field-effect transistors (MOSFETs) and a fabrication method thereof. Gate contact of the MOSFETs is arranged at a side wall of a main groove, source metal contact is formed at the bottom of the groove, electrons flow through an inversion layer at the side wall of the groove from bottom to top to form an inverse conduction channel different from traditional groove-shaped MOSFETs during positive conduction, a high electric field of a body region of a device is effectively shielded by the source metal contact at the bottom of the groove during reverse blocking, so that the gate dielectric field of the device is greatly reduced, and avalanche occurs at a PN junction of the body region of the device. The fabricated silicon carbide groove-shaped MOSFETs have relatively low positive conduction resistance and relatively high reverse blocking capability, and the static and dynamic working reliability of the device can be improved.

Description

technical field [0001] The invention relates to a silicon carbide trench type metal-oxide-semiconductor field effect transistor (MOSFET) structure and a preparation method thereof, in particular to a method for manufacturing silicon carbide trench type MOSFETs with a reverse conduction channel. Background technique [0002] Silicon carbide MOSFET is currently the fastest-growing wide-bandgap power semiconductor device. Compared with traditional silicon materials, silicon carbide has obvious advantages in physical and electrical properties, and plays an extremely important role in energy saving and emission reduction. Among them, MOSFET with vertical silicon carbide trench gate structure has a non-polar channel surface and has higher mobility and higher cell integration, making silicon carbide trench MOSFET a next-generation power electronic device It can be widely used in fields such as electric vehicles, charging piles, uninterruptible power supplies, and smart grids. [0...

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Problems solved by technology

[0003] However, on the one hand, the channel carrier mobility of silicon carbide trench MOSFET is still much lower than that of silicon carbide bulk material, thus reducing the conduction characteristics of the device; on the other hand, due to the critical breakdown electric field of silicon carbide Larger, the electric field in the gate dielectric rises sharply, especially the two-dimensional electric field concentration phenomenon at the groove corner is more serious, which makes the reliability of the gate dielectric of the SiC MOSFET working at high frequency, high temperature and high power greatly improved. reduced, thus detrimental to the long-term stability of the device

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