Trench silicon carbide mosfet device with low power consumption and high reliability

Abstract

The present invention provides a trench silicon carbide MOSFET device with low power consumption and high reliability, comprising: an N-type substrate, an N-type epitaxial layer, a first P-body region, a first P+ contact region, and a first N+ contact region , the second P-body region, the second P+ contact region, the second N+ contact region, oxide layer, groove gate, metal electrode, drain; the SiC MOSFET device proposed by the present invention significantly reduces the on-resistance through parallel connection of 4 channels , through the second P-body wrapping and protecting the gate groove, it not only enhances the reliability of the oxide layer of the device, but also shields part of the gate-drain capacitance to reduce the switching loss of the device; when the device is short-circuited, the first P-body The pinch-off of the JFET region formed by the region and the second P-body region reduces the saturation current of the device and improves its short-circuit capability.

Description

technical field [0001] The invention belongs to the technical field of power semiconductor devices, in particular to a trench type silicon carbide MOSFET device with low power consumption and high reliability. Background technique [0002] As one of the representatives of the third-generation wide bandgap semiconductor materials, silicon carbide (Silicon Carbide) material has a large bandgap (3.26eV) and a high critical electric field (3×10 6 V / cm), high carrier saturation drift velocity (2×10 7 cm / s), high thermal conductivity (490W / Mk), and good thermal stability. It is an excellent material for the preparation of high-voltage power electronic devices. Application prospect. [0003] MOSFET is the most widely used gate-controlled device structure in silicon carbide power devices. Since silicon carbide MOSFET is a device characterized by unipolar transport working mechanism, only one kind of carrier in electrons or holes conducts electricity, and there is no charge storag...

AI Technical Summary

Problems solved by technology

Although the P+ shielding layer at the bottom of the trench gate can strongly protect the oxide layer at the bottom and corners of the trench gate, the oxide layer on the sidewall of the trench will still be challenged by a high electric field in the blocking state, so the P+ shielding layer The introduction cannot completely solve the reliability problem that the trench gate oxide layer is impacted by high electric field

[0005] Due to the poor interface state between the current silicon carbide material and the gate oxide dielectric, the channel mobility is too low, and the conduction characteristics of the trench gate silicon carbide MOSFET are still far from the theoretical limit.

Due to the large gate-to-drain capacitance of the trench-gate SiC MOSFET, its switching loss is high

At the same time, due to its high current saturation current, its short-circuit capability is weak

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