THE SURFACE OF THE (001) SRTIO3-DELTA SUBSTRATE AT HIGH-TEMPERATURE

The temperature dependence of the surface peaks of the polished (001) SrTiO3-delta substrate surfaces was studied up to the deposition temperature of high-T-c, superconducting films by the newly developed high-temperature Rutherford backscattering spectrometry system. The temperature dependence of the Sr surface peaks was found to follow the dependence due to the thermal vibration of the Sr atoms predicted by the theory of Stensgaard et al. However, an anomalous temperature dependence of the Ti surface peak was observed. The Ti surface peaks were found to be maximum at 400 degrees C. The anomalous temperature dependence may be due to the displacement of Ti atoms. Surface reconstruction was observed on the Sr surface sublattice by channeling when the oxygen contents of SrTiO3-delta were reduced to a certain level. However, the anomalous temperature dependence of the Ti surface peak for the reduced SrTiO3-delta disappeared. Surface steps with height close to multiples of the length of a unit cell were observed on the reduced SrTiO3-delta substrate surfaces by atomic force microscopy.