Interference phenomena of synchrotron radiation in TEY spectra for silicon-on-insulator structure

Abstract

The general matrix theory of the photoelectron/fluorescence excitation in anisotropic multilayer films at the total reflection condition of X-rays has been developed. In a particular case the theory has been applied to explain the oscillation structure of L 2,3 XANES spectra for a SiO 2/Si/SiO 2/c-Si sample in the pre-edge region which has been observed by a sample current technique at glancing angles of synchrotron radiation. Remarkably the phase of the oscillations is reversed by a ∼2° angle variation. The observed spectral features are found to be a consequence of waveguide mode creation in the middle layer of strained Si, which changes the radiation field amplitude in the top SiO 2 layer. The fit of the data required the correction of the optical constants for Si and SiO 2 near the Si L 2,3-edges. © 2012 International Union of Crystallography.