SiC MOSFET power device and preparation method thereof

Abstract

The invention provides a SiC MOSFET power device and a preparation method thereof. The device comprises a substrate, an epitaxial layer, a trench, a gate dielectric layer, a gate conductive layer, a well region, a source region, a body contact region, an SBD diode region, a front metal layer and a drain metal layer, wherein the epitaxial layer is positioned on the surface of the substrate; the trench is located in the epitaxial layer, and the upper opening of the trench is larger than the lower opening of the trench; the gate dielectric layer is positioned on the side wall and the bottom surface of the trench; the gate conductive layer is located on the surface of the gate dielectric layer and fills the trench; the well region is located in the epitaxial layer and is located on the periphery of the trench; the source region is located in the well region; the body contact region is located in the well region; the SBD diode region is located in the epitaxial layer. According to the device, the structure of a traditional SiC MOSFET power device is optimized, so that the conduction resistance and the conduction power consumption of the device can be reduced, and the device can also have a relatively low input capacitance, the switch speed of the device is increased, the power consumption of the switch is reduced, the reverse conducting capability of the device is improved, and theoverall size and the economic cost of the power module are reduced. The structure and the method are simple, and a wide application prospect is achieved.

Description

Technical field [0001] The present invention relates to the field of semiconductor device manufacturing, in particular to a SiC MOSFET power device and a preparation method thereof. Background technique [0002] In order to cope with the increasingly serious global energy crisis and environmental pollution problems, it is imperative to develop energy-saving, environmentally friendly and miniaturized power supply systems. The "central processing unit" known as power electronic devices-power switching devices restrict the miniaturization of power supply systems The main factor of development. Silicon Carbide (SiC), as a wide band gap semiconductor material, belongs to the third-generation semiconductor material system. Compared with silicon materials, it has a larger band gap, higher critical breakdown electric field strength, Faster electron saturation drift speed and higher thermal conductivity and other excellent properties, so it is very suitable for preparing high-power, high...

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Problems solved by technology

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a SiC MOSFET power device and its preparation method, which are used to solve the poor reverse conduction characteristics of the existing SiC MOSFET power devices, such as the required reverse conductivity. The conduction voltage drop is large, the reverse recovery time is long, etc., and the introduction of external devices will lead to an increase in the overall size and economic cost of the power module, and when the device is in the blocking state, it will introduce excessive electric field strength in the gate dielectric layer , leading to problems such as device failure due to gate dielectric layer breakdown

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