Exact Characterization of Threshold Voltage Instability in 4H-SiC MOSFETs by Non-Relaxation Method

Abstract

In this work, we investigated the methods that measure the threshold voltage ( V th ) instability without relaxation of the gate stress during the V th measurement. We propose a non-relaxation method that demonstrates exact V th shifts compared with conventional methods that are not as accurate. In the non-relaxation method, the constant gate-source voltage ( V gs ) is continuously applied as a gate stress while the drain voltage ( V d s ) shift required to maintain a constant drain current ( I d ) is measured. Then, the V d s shift is converted to a V th shift. The V th shift values measured by the non-relaxation method are larger than those measured by the other methods, which means that the non-relaxation method can very accurately measure the V th shift.