An Analytical Subthreshold I–V Model of SiC Double Gate JFETs

Abstract

SiC double gate (DG) junction field effect transistor (JFET) is promising for low-noise and high-temperature electronics. Existing studies indicate that JFETs can be considered a special case of MOSFETs when the oxide layer thickness approaches zero. In this article, we exploited the structural similarity between the DG JFETs and the DG MOSFETs. By obtaining the 2D Poisson's equation for the DG MOSFETs and deriving the limits, we developed a model for calculating the channel current of SiC DG JFETs in the subthreshold region. The model is derived from device physics, requiring no fitting parameters and offering relatively low computational complexity. The results indicate that, whether for enhancement mode or depletion mode JFETs, the calculated values of this model are in good agreement with the 2D numerical analysis results obtained from Silvaco Atlas. Moreover, for enhancement mode JFETs, even when significant short-channel effects occur, the subthreshold current can still be well predicted. In addition, the model displays predictive capability for the depletion-mode JFETs.