Real-Time Extraction of SiC mosfets’ Degradation Features Under Improved Accelerated Power Cycling Tests for DC-SSPC Application

Abstract

The SiC MOSFET is a key component of the DC Solid-State Power Controller (DC-SSPC). The reliability of DC SSPCs can be improved by real-time online monitoring the degradation of SiC MOSFETs. At present, the degradation of SiC MOSFETs can be indirectly monitored using thermo-sensitive electrical parameters(TSEPs), however, their degradation can cause non-negligible measurement errors. Another limitation is that one type TSEPs can only reflect a certain form of degradation processs. Basis on this, in this paper, the real-time extraction method of SiC MOSFETs' degradation features under improved accelerated power cycling tests for DC SSPC application (i.e., average and standard deviation of on-resistance change rate ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">avgk</i> , <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">stdk</i> ) of the improved accelerated power cycling test) is proposed. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">avgk</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">stdk</i> can be easily obtained by simple calculations. This method can not only directly monitor the severe degradation of bonding wires, but also monitor the severe degradation of the solder layer without measuring the junction temperature ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$T_{J}$</tex-math></inline-formula> ). Compared with the traditional solder layer degradation feature extraction method using thermal resistance which <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$T_{J}$</tex-math></inline-formula> is essential, the monitoring results using the proposed method are not affected by the degradation of TSEPs. Finally, the effectiveness of the proposed method is verified by experiment results.