Characterization of SiC JFET for Temperature Dependent Device Modeling

Silicon carbide (SiC) is considered the wide band gap semiconductor material that can presently compete with silicon (Si) material for power switching devices. Compact circuit simulation models for SiC devices are of utmost importance for designing and analyzing converter circuits; in particular, if comparisons with Si devices will be performed. The SiC power switching device structure and composition inevitably differs from those of conventional Si devices so as to harness the superiority of the material. The operational characteristics of the device thus are different from those of conventional Si devices. These characteristics cannot be accurately predicted by current Si power device models. Hence, the motivation to develop circuit simulation models for SiC devices. Moreover, SiC transistors have not been characterized as thoroughly as diodes. This paper characterizes SiC JFETs for the purpose of modeling and parameter extraction which can then be utilized in circuit simulations. The characterization is based on the dc (current-voltage) characteristic measurements using a curve tracer and on the ac (capacitance [impedance] - voltage) measurements using an impedance analyzer. Noting that characterization data for SiC JFETs are only available up to an ambient temperature of 250degC, the device is characterized from room temperature to 450degC demonstrating the high temperature operation of SiC JFETs. To this end, the devices were packaged in dedicated high temperature packages, and measurement fixtures were specially fabricated to withstand high ambient temperatures. The body diode buried in the evaluated SiC JFET is also characterized for potential synchronous rectifier applications