Electronic defect states at annealed metal∕4H–SiC interfaces

Abstract

We have used low energy electron-excited nanoscale luminescence spectroscopy (LEEN) to study the formation of electronic surface states at metal∕4H–SiC contacts. These junctions were formed using both low and high reactivity metals to study how the nature of interface chemical bonding affects the interface state formation. We observe evidence for the formation and removal of localized states at energies that have been associated with morphological SiC defects. Metals such as Au and Ag with no strong chemical reactivity exhibited the most pronounced changes. Conversely, chemically-reactive metals such as Ti and Ni exhibited only minor changes and only with high temperature annealing. These observations suggest that native defects rather then metal-specific chemical bonding dominate the interface electronic features.