Peculiarities of impact ionization of Impurity Al in SiC polytypes

摘要

The specific character of impact ionization of a small radius impurities was investigated in polytypesn6H-, 4H-, and 15R-SiC. The I-V characteristics of Al breakdown in 6H-, 4H-, and 15R-SiC innelectrical field were studied. It was shown that at 77 K the impurity breakdown takes place onlynunder the large impurity concentrations u0002three orders larger than that in Geu0003. The following datanwere obtained: the decreasing dependence of breakdown field due to the concentration increase, thenabsence of the low temperature breakdown at low impurity concentration, and gigantic enhancementnof breakdown field when the field is parallel to the crystal axis. © 2010 American Institute ofnPhysics. u0004doi:10.1063/1.3527964