CARBON CLUSTER MODEL FOR ELECTRONIC STATES AT SIC SIO2 INTERFACES/

The electronic properties of the SiC/SiO2 interface are studied for a series of SiC polytypes (3C, 4H, 6H) using various electrical methods and internal photoemission spectroscopy. The energy distribution of st ates at SiC/SiO2 interfaces is found to be similar for all the investi gated polytypes. The lowest density of states measured at SiC/SiO2 int erfaces is at least one order of magnitude higher than the density of states at Si/SiO2 interfaces. We have strong indications that this enh ancement is caused by residual carbon (graphite-like films, carbon clu sters) bonded at the SiC/SiO2 interface. We propose a ''carbon cluster model'', which qualitatively describes the electrical properties of ( 3C, 4H, 6H)-SiC MOS structures. (C) 1997 Elsevier Science S.A.