An analytical subthreshold I–V model of SiC MOSFETs

Abstract

In this article, an analytical I–V model for calculating subthreshold current of SiC MOSFETs is presented. This model starts with planar MOSFETs and utilizes the one-dimensional Poisson’s equation to derive an analytical expression for the surface potential. Subsequently, it employs this expression as a foundation for subthreshold current calculations. Then the model is extended to DMOSFETs based on the fact that channel current formation mechanism of DMOSFETs is similar to that of planar MOSFETs. Comparative analysis of our model calculations with two-dimensional numerical simulation software reveals that our model exhibits a high degree of agreement in the case of planar MOSFETs and DMOSFETs. Interface traps were also considered in our analytical model, which agrees well with experimental data published elsewhere. Furthermore, the model retains a certain degree of accuracy and predictive capability even in the presence of short-channel effect. Our subthreshold model becomes complementary to existing models which only describe the I–V characteristics of SiC MOSFETs when the transistors operate above the threshold voltages.