A method to distinguish the cause of degradation of sic MOSFET under repeated surge current of body diode

Abstract

The invention discloses a method for distinguishing the degradation cause of SiC MOSFET under repeated surge current of body diode. The single surge current capability of SiC MOSFET body diode is determined through single surge current experiment, and the static characteristics and dynamic characteristics of SiC MOSFET are measured. characteristics, conduct repeated surge current tests, compare the static and dynamic characteristics of SiC MOSFETs and the degradation of extracted parameters after surge current tests, identify the causes of device degradation, and determine whether bipolar degradation is included in the degradation causes of SiC MOSFETs, and compare Body diode characteristics or changes in body diode voltage drop, determine whether the degradation of SiC MOSFET includes package degradation, whether gate oxide degradation is included, and compare the transfer characteristics or threshold voltage changes at low currents to achieve an effective solution to the cause of degradation Coupling is beneficial to understand 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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