SI-29 HYPERFINE-STRUCTURE OF THE P-B1 INTERFACE DEFECT IN THERMAL (100)SI SIO2/

The observation of the electron spin resonance hyperfine (hf) spectra associated with the unpaired electron of the For interface defect in t hermal (100)Si/SiO2 shows that the dominant interaction arises from a single Si-29 isotope. The hf tensor displays weakly monoclinic I (near ly axial) symmetry, with the principal axes of the g and hf tensors co inciding. A molecular orbital analysis indicates that the unpaired ele ctron resides for similar to 58% in a single unpaired Si hybrid orbita l, found to be 14% s-like and 86% p-like, with the p-orbital markedly pointing closely along a [211] direction at 35.26 degrees with the [10 0] interface normal. With oxygen not constituting an immediate part of the defect, the results firmly establish the key part of the P-b1 def ect as a tilted (similar to 20 degrees about [011]) Si-3=Si unit.