Ravindranath Droopad

Direct observation of atomic disordering at the SrTiO3/Si interface due to oxygen diffusion

The stability of epitaxially grown single crystal SrTiO 3 (001) thin films on Si(100) substrates was studied as a function of temperature under vacuum and oxygen-rich environments using Rutherford backscattering spectrometry in channeling geometry, nuclear reaction analysis, and x-ray photoelectron spectroscopy. During vacuum annealing, it was found that interfacial silica formed due to diffusion of oxygen from the film to Si. This was further accompanied by the atomic disordering of Sr, Ti, and O sublattices in the film due to reduction reactions. Although the interfacial degradation process is similar during heating in oxygen environment, no disordering of the film was observed.