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

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.