Threshold Voltage Instability of 1200V SiC MOSFET Devices

1200V 4H-SiC MOSFETs have been designed and fabricated sucessfully. The drain current I_d = 20 A at Vg = 20 V, corresponding to V_d = 2.0 V. The stability of threshold voltage was studied soon. It is believed that the instability in device behavior during gate bias stress is due to capture of electrons by the SiC/gate dielectric interface traps and the gate dielectric near interface traps. A constant gate voltage of +20V/-10V is applied to the gate at a temperature of 150°C. The threshold voltage are monitored for device stability. Compare with three other commercial devices, the devices show little variation in the V_th.