Characterization of various crystalline structures at the SiO2/Si interface by positrons

The nature of the interface of the Si (0 0 1) surface with grown, native oxide is examined by a slow-positron beam equipped with coincidence Doppler broadening (DB). Measurements are combined with theoretical calculations of high-momentum DB profiles of Si, divacancy in Si, Brazilian quartz and the interface itself. From this comparison, the conclusion is drawn that an ordered structure exists at the interface. This structure resembles low quartz or a SiO2 structure with a lower density than low quartz.