Papers by Author: R.J. Kumar

Abstract: The on-state and switching performance of high voltage 4H-SiC junction rectifiers are compared using numerical simulations and experimental characterization. Epitaxial and implanted anode PiN diodes as well as novel, advanced rectifiers have been fabricated in 4H-SiC using 110μm thick drift layers. The relatively low forward voltage drop of these epi-anode diodes (4.2V @ 100A/cm2) indicates moderate conductivity modulation, while the superior switching performance of the “MPS-like” rectifiers is demonstrated with reverse recovery characteristics at various temperatures and forward current densities.

Abstract: A Microwave Photoconductivity Decay (M-PCD) technique which senses changes insample conductivity as carriers recombine following excitation by a laser pulse, has been used to determine the minority carrier recombination lifetime from the decay rate of carriers in 4H-SiC epitaxial layers. Decay times varying from 60 ns to 500 ns have been measured, with the decay increasing with thickness. Device simulations show that I-V characteristics of pin diodes fabricated with these epitaxial layers are compatible with the observed decay times.