Carrier Concentration Analysis in 1.2 kV SiC Schottky Diodes Under Current Crowding

Die-level current crowding phenomena are analyzed at the microsecond timescale with an internal IR-Laser Deflection set-up. To this end, the 4H-SiC plasma-optical coefficient for the refractive index is reported for the first time. A SiC Schottky diode with an edge termination based on a junction termination extension is used as a test vehicle. Under biasing conditions, the edge termination starts a local bipolar conduction along the device active area perimeter, leading to current crowding effects. Using refractive index measurements, a depth-resolved carrier profile is extracted and assessed using both, simulation and Free Carrier Absorption measurements.