Accounting for anomalous oxidation states of silicon at the Si/SiO2 interface

The early oxidation stages of hydrogen-terminated single-crystalline Si(100) exposed to a diluted N-2/N2O atmosphere at 850degreesC for different durations have been studied by XPS, following the evolution of the Si 2p signal. Evidence is given that the usual analysis, in terms of five pairs of peaks attributed to silicon in oxidation states from 0 to +4, does not account for the observed Si 2p signal. The spectrum is accurately reproduced only by assuming the existence of silicon in bonding configurations different from those usually assumed to occur at the Si/SiO2 interface. Copyright (C) 2002 John Wiley Sons, Ltd.