SiC GTOs Thyristor for Long Term Reliability on Pulsed Power Application Test

Silicon Carbide (SiC) is a wide-bandgap semiconductor with a wider bandgap, higher critical electric field, higher saturation velocity, and higher thermal conductivity than silicon, making it desirable for pulsed power applications. The n-type Gate Turn-off thyristor (nGTO) is a controllable solid-state switch with high blocking voltage and high current conduction capabilities. However, its device structure is challenging to develop using SiC. Wolfspeed has developed a 15.0 kV SiC nGTO that withstood peak current up to 1.0 kA. A testbed was developed to evaluate the long-term reliability of these SiC nGTOs. The pulser operates with a capacitor bank charged to 10.0 kV to deliver a 35.0 µs ring-down current waveform through the device. The SiC nGTOs were pulsed with a repetition rate of 0.5 Hz. It was observed that the device dissipated 700.0 J peak energy during pulsing. COMSOL Multiphysics simulated the SiC nGTO during a single pulsing event. The simulation models the thermal flow and current density in the nGTO. The thermal result shows the peak device temperature rising to 360.1 K after 17 µs into the pulsing event. The peak magnitude of current density reached 15 kA/cm2