Angle-resolved XPS studies on transition layers at SiO₂/Si interfaces

Using the high-brilliance synchrotron radiation at super photon ring 8 (SPring-8) we determined the electron escape depths in approximately 1-nm-thick low-temperature oxide layers, which were formed on Si(1 1 1) at 300 °C using three kinds of atomic oxygen, and that in approximately 1-nm-thick thermally grown oxide layer formed in 1 Torr dry oxygen at 900°C by measuring Si 2p photoelectron spectra at the photon energy of 1050 eV. The results indicated that the electron escape depths in the three kinds of low-temperature oxide layers were 13-21% smaller than that in the thermally grown oxide layer. Furthermore, the electron escape depth in the thermally grown oxide layer, whose thickness was close to that of the structural transition layer, was 19% smaller than that in bulk SiO₂.