EBIC investigation of edge termination techniques for silicon carbide power devices

Various edge termination techniques for silicon carbide power devices were investigated for their effectiveness in improving the breakdown characteristics using the Scanning Electron Microscope (SEM) in the Electron Beam Induced Current (EBIC) mode. This paper reports an EBIC analysis of the experimentally obtained results for three termination techniques: (a) Floating Metal field Ring (FMR) (b) REsistive Schottky barrier field Plate (RESP) (c) Argon Ion Implant termination. Argon Ion Implant termination was found to be most effective in spreading the depletion boundary at the surface. EBIC analysis on the RESP terminated diodes revealed that insufficient sheet resistance of the RESP layer caused an early breakdown in these diodes. FMR terminated diodes exhibited spreading of the depletion region beyond that indicated by numerical simulations without surface charge. Simulations performed to study the effect of negative surface charge indicate that a charge density of more than 1×10¹¹ cm ^-2 was required to cause substantial spreading of the depletion edge