Avalanche breakdown of 4H-SiC diodes with edge terminated by a 2/spl deg/ positive bevel

The authors present attempts toward obtaining impact ionization rates of both holes and electrons. Diodes terminated by a 2/spl deg/ positive bevel have been fabricated with the anode area ranging from 10/sup 4/ /spl mu/m/sup 2/ to 3x10/sup 5/ /spl mu/m/sup 2/. The breakdown voltages were measured. The multiplication factors of electrons and holes have been calculated based on the photocurrent measured at 230 nm and 370 nm. The impact ionization rates of holes and electrons are calculated from the multiplication results.