The purpose of this article is to report the results of an experiment designed to investigate the density of interface states (DOS) measured at the Si-SiO2 interface immediately following rapid thermal annealing (RTA) (1040degreesC) in a nitrogen (N-2) ambient. This work extends previous publications on Si(100) by examining (111), (110), and (100) silicon orientations. The DOS profiles were examined using a mercury probe capacitance-voltage technique, and characteristic peaks in the DOS across the energy gap were obtained for all orientations. Consideration of there results in relation to other works indicates that the peak features in the DOS profile after an RTA in N-2 are a consequence of unpassivated dangling bond defects for the respective orientations. The significance of these results is considered.