“Carbon cluster model” for electronic states at interfaces

Abstract The electronic properties of the SiC SiO 2 interface are studied for a series of SiC polytypes (3C, 4H, 6H) using various electrical methods and internal photoemission spectroscopy. The energy distribution of states at SiC SiO 2 interfaces is found to be similar for all the investigated polytypes. The lowest density of states measured at SiC SiO 2 interfaces is at least one order of magnitude higher than the density of states at Si SiO 2 interfaces. We have strong indications that this enhancement is caused by residual carbon (graphite-like films, carbon clusters) bonded at the SiC SiO 2 interface. We propose a “carbon cluster model”, which qualitatively describes the electrical properties of (3C, 4H, 6H)-SiC MOS structures.