6.9-cm Active-area interconnected wafer 4 kV PiN diode pulsed at 55 kA

Abstract

SiC device area is presently limited by material and processing defects. To meet the large current handling requirements of power conditioning systems, paralleling of a large number of devices is required. This can increase cost and complexity through dicing, soldering, insertion of ballast resistors, and forming multiple wire bonds. Furthermore, paralleling numerous discrete devices increases package volume/weight and reduces power density. To overcome these complexities, seventy nine PiN diodes were interconnected on a three-inch 4H-SiC wafer to form a 6.9-cm2 active-area full wafer diode. The interconnected wafer diode blocked a voltage of 4 kV at an extremely low leakage current density of 0.07 μA/cm2. The wafer diode was subsequently mounted in a "hockey puck" package and subjected to high power pulsed testing, wherein initial energy stored in a capacitor bank discharged through the interconnected wafer diode into a resistive load. At a pulsed current density of 8 kA/cm2 and a rise rate of di/dt=1.3 kA/μs, the interconnected wafer diode conducted a peak current of 54.8 kA and dissipated 149 J. The calculated action was 420 kA2-s.