Study of bulk and elementary screw dislocation assisted reverse breakdown in low-voltage (>250 V) 4H-SiC p/sup +/-n junction diodes. II. Dynamic breakdown properties

Abstract

For Part I see ibid., vol.46, no.3, pp.478-84 (Mar. 1999). This paper outlines the dynamic reverse-breakdown characteristics of low-voltage (<250 V) small-area <5/spl times/10/sup -4/ cm/sup 2/ 4H-SiC p/sup +/-n diodes subjected to nonadiabatic breakdown-bias pulsewidths ranging from 0.1 to 20 /spl mu/s 4H-SiC diodes with and without elementary screw dislocations exhibited positive temperature coefficient of breakdown voltage and high junction failure power densities approximately five times larger than the average failure power density of reliable silicon pn rectifiers. This result indicates that highly reliable low-voltage SiC rectifiers may be attainable despite the presence of elementary screw dislocations. However, the impact of elementary screw dislocations on other more useful 4H-SiC power device structures, such as high-voltage (>1 kV) pn junction and Schottky rectifiers, and bipolar gain devices (thyristors, ICBT's, etc.) remains to be investigated.