INTERFACIAL REACTION BETWEEN DISILANE AND A GE(111)C(2X8) SURFACE

We present photoemission results on the thermal and catalytic decomposition of disilane (Si2H6) on a monocrystalline Ge(111)c(2 x 8) surface. Catalytic decomposition of disilane is obtained at a hot tungsten filament. Germanium substrates were heated by the Joule effect in the 20-600-degrees-C temperature range and exposed to low pressure (10(-5) Torr) Si2H6 doses. The thicknesses of the Si layers deposited by both methods were estimated from X-ray photoemission spectroscopy (XPS) measurements. Valence band ultraviolet photoemission spectroscopy (UPS) is used to characterize the crystalline quality of the deposited films. The growth rate of the Si film is found to be 10 times higher when obtained after catalytic decomposition rather than by thermal decomposition of disilane. For substrate temperatures above 400-degrees-C, we observe a silicon-germanium intermixing.