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.