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The interface between silicon (100) and thermal silicon dioxide grown by wet, dry, and trichloroethylene oxidation has been investigated by scanning tunneling microscopy and scanning tunneling spectroscopy. The scanning tunneling microscopy images of the silicon surface, after removal of oxide, reveal the presence of silicon bumps (protrusions) in samples prepared by wet and dry oxidation while no protrusions are seen at the interface of trichloroethylene oxidized samples. The spectroscopic measurements predict that these are silicon protrusions and are produced by oxide growth conditions. X-ray photon spectroscopy on samples containing protrusions also supports the above prediction. Thus, our study suggests that roughness of the silicon–silicon dioxide interface depends on oxide growth conditions and a relatively smooth interface is obtained by tricholoroethylene oxidation.

Electrical properties and surface morphology of heteroepitaxial-grown tin-doped indium oxide thin films deposited by molecular-beam epitaxy Thermal oxides were grown on different doped polysilicon thin films: (i) as-grown polysilicon at 620 ·C, (ii) as-grown polysilicon and annealed at 1000 and lloo·C in nitrogen, and (iii) asgrown amorphous silicon films at 570 ·C subsequently converted into polycrystalline form during doping. These films are qualitatively characterized by studying electrical properties, such as leakage current, breakdown field, the temperature dependence of current, and the time dependence of current. The electrical measurements of oxides grown on polysilicon converted from amorphous form show lower leakage current and higher dielectric breakdown than oxides grown on as-deposited poly silicon films. The results were interpreted in terms of interface texture of polysilicon/polyoxide using the Fowler-Nordheim tunneling mechanism. The temperature dependence of current through the oxides shows little variation at low temperatures, but it increases exponentially at high temperatures. The oxides also exhibit a time-dependent current. This dependence could be ascribed to ionic-Ohmic conduction of charge carriers in the polyoxide, at low fields and high temperatures.

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