Characterization of the SiO2/Si interface by positron annihilation spectroscopy -: art. no. 195331

The densification of SiO2 on silicon towards the interface, as already concluded in a recent work, is confirmed to exist in thinner oxides obtained by etching, and in a native oxide too. Furthermore, an annihilation state is revealed in the thermally grown and etched, as well as a native, oxide which must resemble low quartz in its structure. A lower limit d=(2.2+/-0.1) nm of the thickness of the interface layer resembling low quartz in its structure can be estimated. A variety of the state-of-the-art theoretical calculations to aid the experimental findings is summarized. It is discussed why the presented results corroborate the model of quasiepitaxial oxide growth and pseudopolymorphic relaxation of the grown oxide.