Geometrical effects in high current gain 1100-V 4H-SiC BJTs

Abstract

This paper reports the fabrication of epitaxial 4H-SiC bipolar junction transistors (BJTs) with a maximum current gain /spl beta/=64 and a breakdown voltage of 1100 V. The high /spl beta/ value is attributed to high material quality obtained after a continuous epitaxial growth of the base-emitter junction. The BJTs show a clear emitter-size effect indicating that surface recombination has a significant influence on /spl beta/. A minimum distance of 2-3 /spl mu/m between the emitter edge and base contact implant was found adequate to avoid a substantial /spl beta/ reduction.