ROLE OF DEFECTS IN PRODUCING NEGATIVE TEMPERATURE-DEPENDENCE OF BREAKDOWN VOLTAGE IN SIC

Electron beam induced current (EBIC) techniques were employed in order to understand the role of defects on the breakdown characteristics of SiC. EPIC images revealed that certain defects caused enhanced multip lication leading to the catastrophic failures in SiC diodes. The impac t ionization coefficients for holes measured at the defective site (al pha(p,eff)) were found to be higher than those measured at the defecti ve site was found to increase measured at a nondefective site. Also, a lpha(p,eff) with increasing temperature in contrast with a defect free diode where alpha(p) decreases with increasing temperature, clearly i ndicating that the defects produce the observed negative temperature c oefficient of breakdown voltage in SiC. (C) 1998 American Institute of Physics.