CHARACTERIZATION OF SILICON-CARBIDE JFETS WITH RESPECT TO MICROSYSTEMS FOR HIGH-TEMPERATURE APPLICATIONS

In this work first commercially available SiC-transistor prototypes we re tested with regard to their applicability in high temperature elect ronic circuits for sensor signal conditioning. The influence of the te mperature on the device behaviour (drain-saturation current, gate leak age current, I-V-characteristics, long-term effects) was investigated. The devices showed reliable operation up to 450 degrees C. The maximu m forward transconductance g(m) and the short circuit drain source cur rent I-DSS decreased to approximately 30% of the room temperature valu es. Also, a slight increase of the pinch-off voltage V-p was observed. The gate leakage current I-GSS rose with temperature, staying below 1 mu A at 450 degrees C. A pre-ageing study was carried out to verify c hanges in the device characteristics with time. The devices were expos ed to a 270 degrees C environment and it was observed that the DC para meters tend to stabilise after about 100 h. From the I-V-characteristi cs the SPICE parameters were extracted for a series of temperatures, a llowing the design and optimisation of amplifier gain stages. The SPIC E device simulation results are in good agreement with the measured ch aracteristics.