Method for distinguishing degradation reason of SiC MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) under repeated surge current of body diode

Abstract

The invention discloses a method for distinguishing a degradation reason of a SiC MOSFET under repeated surge current of a body diode. The method comprises steps of determining the single surge current capability of the SiC MOSFET body diode through a single surge current experiment; measuring the static characteristic and the dynamic characteristic of the SiC MOSFET; performing repeated surge current tests, comparing the static characteristics and the dynamic characteristics of the SiC MOSFETs after the surge current tests and degradation of the extracted parameters; distinguishing cause of degradation of device, determining whether the degradation reason of the SiC MOSFET comprises bipolar degradation or not; by comparing the characteristics of the body diode or the change of the voltagedrop of the body diode, determining whether the degradation reason of the SiC MOSFET comprises package degradation and gate oxide degradation or not, and comparing the transfer characteristic under small current or the change of threshold voltage, achieving effective decoupling of the degradation reason, and facilitating understanding of the failure mechanism of the device.

Description

technical field [0001] The invention belongs to the field of SiC power semiconductor devices, and in particular relates to a method for distinguishing the degradation cause of a SiC MOSFET under repeated surge current of a body diode. Background technique [0002] Compared with the semiconductor Si material, the wide bandgap semiconductor SiC has a larger band gap (3 times that of Si), a higher thermal conductivity (3 times that of Si), a high critical breakdown field strength (10 times that of Si), Higher electron saturation velocity (2 times that of Si) and other more excellent material properties, its temperature resistance, radiation resistance, heat dissipation, and pressure resistance are stronger, and the applicable frequency is higher, and it is widely used in high power density and high conversion efficiency in the power electronic system. In power electronics applications, if the internal parasitic anti-parallel PIN body diode of SiC MOSFET is directly used instea...

AI Technical Summary

Problems solved by technology

Recent studies have shown that commercial SiC planar MOSFETs suffer significant degradation under repeated surge current stress on the body diode, seriously affecting their reliability

[0004] The possible reasons for the degradation of SiC MOSFETs under the repeated surge current stress of the body diode include gate oxide degradation, bipolar degradation, and package degradation. effective decoupling

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