MOSFET device with silicon carbide inverted T-shaped masking layer structure and preparation method thereof

Abstract

The invention relates to an MOSFET device with a silicon carbide inverted T-shaped marking layer structure and a preparation method thereof. The MOSFET device comprises a gate dielectric layer, a base region, a masking layer, a drift layer, a substrate layer, a drain electrode, a polycrystalline silicon layer, a grid electrode, a first source region, a second source region and a source electrode, wherein the base region is located at two sides of the gate dielectric layer; the masking layer is located on the lower surface of the gate dielectric layer; the drift layer is located on the lower surfaces of the base region and the masking layer; the substrate layer is located on the lower surface of the drift layer; the drain electrode is located on the surface of the substrate layer; the polycrystalline silicon layer is located on the inner surface of the gate dielectric layer; the grid electrode is located on the upper surface of the polycrystalline silicon layer; the first source region is located on the upper surface of a part of the base region; the second source region is located on the upper surface of the rest of the base region; and the source electrode is located on the upper surfaces of the first source region and the second source region. According to the MOSFET device, the electric field distribution at the corner of the gate dielectric layer is changed through the P+ type masking layer at the bottom of the trench gate, the electric field concentration at the corner of the device is reduced, the breakdown voltage of the device is improved, and the reliability of the device is improved.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, and in particular relates to a MOSFET device with a silicon carbide inverted T-shaped masking layer structure and a preparation method thereof. Background technique [0002] Silicon carbide, a wide bandgap semiconductor material, has excellent physical and chemical properties such as large bandgap width, high critical breakdown electric field, high thermal conductivity and high electron saturation drift velocity, and is suitable for high temperature, high pressure, high power, and radiation resistance semiconductor devices. In the field of power electronics, power MOSFET devices have been widely used. It has the characteristics of simple gate drive and short switching time. [0003] In the traditional groove gate structure MOSFET, the electric field concentration at the corner of the gate dielectric layer leads to the breakdown of the gate dielectric layer, causing the breakdown of the ...

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Problems solved by technology

[0003] In the traditional groove gate structure MOSFET, the electric field concentration at the corner of the gate dielectric layer leads to the breakdown of the gate dielectric layer, causing the device to break down below the rated breakdown voltage, which seriously affects the forward blocking characteristics of the device

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