Contribution of interface roughness to the infrared spectra of thermally grown silicon dioxide films

Interfacial oxide structures were studied by Infrared reflection absorption spectroscopic analysis. The longitudinal optical mode of the interfacial o xide films arose with lower frequencies and wider widths. We assumed and la ter verified that these changes resulted from the contribution of interfaci al roughness. We therefore examined the contribution of interfacial roughne ss to the infrared spectra using the effective medium approximation model a nd via infrared spectra simulation. The experimental results explained by a model of that interface had an atomically roughness of within 1 nm and che mical structure changes effectively little fluctuation. (C) 1999 American I nstitute of Physics. [S0021-8979(99)04808-2].