11.72-sq cm Active-Area Wafer Interconnected PiN Diode Pulsed at 64 kA Dissipates 382 J and Exhibits an Action of 1.7 MA(sup 2)-s

Abstract : The Silicon carbide (SiC) device area is presently limited by material and processing defects. To meet the large current handling requirements of modern power conditioning systems, the paralleling of a large number of devices is required. This can increase costs and complexity through wafer dicing, device soldering, the inclusion of ballast resistors, and the formation of multiple wire bonds. Furthermore, paralleling numerous discrete devices increases package volume and weight and reduces power density. To overcome these complexities, PiN diodes were designed, fabricated at 83% yields, tested, and interconnected on a 3-inch 4H-SiC wafer to form an 11.72-sq cm active-area full-wafer diode. The full-wafer diode exhibited a breakdown voltage of 1790 V at an extremely low leakage current density of less than 0.002 mA/sq cm. At a pulsed current density of 5.5 kA/sq cm and a rise time of di/dt = 1.1 kA/microseconds, the peak current through the wafer-interconnected diode was 64.3 kA with a forward voltage drop of 10.3 V. The dissipated energy was 382 J and the calculated action exceeded 1.7 MA(sup 2)-s. Preliminary efforts to produce high-voltage diode interconnections have produced quarter-wafer interconnected PiN diodes with breakdown voltages of 4 kV and 4.5 kV and active areas of 3.1 sq cm and 2.2 sq cm, respectively. High-voltage full-wafer diode interconnections will be the focus of future work.