Interface trap passivation for SiO ₂/(0001̄) C-terminated 4H-SiC

Interface trap passivation at the Si O2 carbon -terminated (000 1-) face of 4H-SiC utilizing nitridation and hydrogenation has been evaluated. The Si O2 SiC interface, created by dry thermal oxidation on the C face, shows appreciably higher interface state density near the conduction band compared to the (0001) Si face. A postoxidation anneal in nitric oxide followed by a postmetallization anneal in hydrogen results in dramatic reduction of the trap density by over an order of magnitude near the conduction band. The electrical measurements have been correlated with the interfacial chemistry.