Influence of different illumination profiles on the on-state resistances of silicon carbide photoconductive semiconductor switches

Abstract

Characteristics of a silicon-carbide (SiC) photoconductive switch under different illumination profiles are presented. We triggered a V-doped semi-insulated 6H-SiC switch with lateral geometry using a laser beam of 532-nm wavelength. Photoconductivity tests for different spot profiles and locations show that such switches achieve a minimum on-state resistance when the switching gap is illuminated. The differences between on-state resistances are small for various partial illuminations of the switching gap. Semiconductor modeling is used to simulate the electric field and current profiles for different partial illuminations. The simulation results show poor on-state switch performance when partially illuminated. Based on these results, a more revealing circuit model for the switch matches well with experimental results for partial illuminations.

Application of an Al-doped zinc oxide subcontact layer on vanadium-compensated 6H–SiC photoconductive switches

“…This indicates a larger on-state resistance for PCSS-V3, despite the contact resistance being reduced by the n + -AZO thin film. This may be attributed to a long absorption depth of the 532-nm laser in 6H-SiC (absorption coefficient is 2 cm −1 at 532 nm [25] ), enabling some laser to penetrate directly through the whole PCSS device without being effectively absorbed.…”