Direct observation and three dimensional structural analysis for threading mixed dislocation inducing current leakage in 4H-SiC IGBT

Abstract

The Burgers vector and inclination angles for threading dislocations which induce current leakage have been investigated for SiC insulated gate bipolar transistors fabricated with a thickness of a drift layer as large as 100 μm on a 4H-SiC substrate. Direct analysis by convergent-beam electron diffraction to a threading mixed dislocation (TMD) inducing current leakage revealed that the Burgers vector was b = [1011], which has been theoretically predicted but had not been observed. Although a range of inclination zenith angles of TMDs from c-axis has been observed by non-destructive two-photon-excited photoluminescence as 12°-14°, which is in good agreement with theoretical values, their azimuthal angles on (0001) plane are significantly different from theoretical predictions.