Second-harmonic response of chemically modified vicinal Si(111) surfaces

Abstract

We have studied the optical second-harmonic (SH) response of vicinal Si(111) interfaces, H-terminated or covered with a thermally grown oxide film and subjected to different annealing temperatures. We observed that the rotational anisotropy of the SH signal of a thermally grown oxide film changes after an annealing procedure. We explain this result from a modification of atomic bonding at the steps of the surface. The change in amplitude and phase of the nonlinear-optical response can be well described with an anharmonic oscillator model. We found that the nonlinear-optical signal can be correlated with the electrical quality (density of interface traps) of metal-oxide semiconductor devices produced from these Si/${\mathrm{SiO}}_{2}$ structures.