Improved empirical DC I–V model for 4H-SiC MESFETs

Abstract

A novel empirical large signal direct current (DC) I-V model is presented considering the high saturation voltage, high pinch-off voltage, and wide operational range of drain voltage for 4H-SiC MESFETs. A comparison of the presented model with Statz, Materka, Curtice-Cubic, and recently reported 4H-SiC MESFET large signal I-V models is made through the Levenberg-Marquardt method for fitting in nonlinear regression. The results show that the new model has the advantages of high accuracy, easily making initial value and robustness over other models. The more accurate results are obtained by the improved channel modulation and saturation voltage coefficient when the device is operated in the sub-threshold and near pinch-off region. In addition the new model can be implemented to CAD tools directly, using for design of 4H-SiC MESFET based RF&MW circuit, particularly MMIC (microwave monolithic integrate circuit). 4H-SiC MESFET, DC I-V characteristics, empirical model, Levenberg-Marquardt method, nonlinear regression

One-directional 3D-SiC MESFET for high power applications

“…The threshold voltage decreases with the increase in channel doping. This decrease can be explained by equation (2). As the doping increases, V p0 increases, and this results in the decrease of the threshold voltage, as shown from equation (1).…”

“…, (2) V T is the threshold voltage, V bi is the built-in potential, V p0 is the pinch off voltage, q is the charge of an electron, N D is the channel doping, a is the channel thickness, and ε is the dielectric constant of 3C-SiC. The Mathcad simulation has shown that the threshold voltage of this device is about -4.5V.…”

“…SiC MESFETs have been reported by many groups [2][3]. The advantage of MESFETS is that it has higher carrier mobility in the channel, compared with MOSFETs.…”