Numerical and Experimental Investigation on Bipolar Operation of 4H-SIC Normally-on Vertical JFETs

Abstract

It is well known from the literature published on Si devices that junction field effect transistors (JFETs) can be either operated in a unipolar mode (when the gate junction bias is less than 0.4 V) or in a bipolar mode (when the gate junction inject minority carriers into the channel/drift region to modulate its resistance)- The latter mode of operation is typically used to improve the on-state performance of normally-off JFETs. The aim of this paper is to investigate the bipolar mode of operation of 4H-SiC normally-on vertical JFETs. Both numerical and experimental results will be used to conclude whether the bipolar mode of operation offers any clear advantages to SiC normally-on JFETs. The influence of high temperature operation (up to 300degC) on the on-state characteristics will also be considered