SiC film formation from C ₆₀ monolayer on Si(111)-(7 x 7) and Si(001)-(2 x 1) surfaces studied by HREELS-STM

We have investigated the thermal reaction of C ₆₀ molecules and the formation of SiC films on Si(111)-(7 X 7) and Si(001)-(2 X 1) surfaces by the combined measurements of high-resolution electron-energy-loss spectroscopy (HREELS) and scanning tunnelling microscopy (STM), HREELS-STM. The surface phonon energy of SiC film, formed by heating the 1 ML film of C ₆₀ adsorbed on Si(111)-(7 X 7) and Si(001)-(2 X 1) surfaces up to 900°C, is observed at 114 meV. Moreover, new peaks are measured at 91 and 102 meV in high resolution measurements. Taking into account the cross sections and the angular profiles of the scattered electrons, we attribute the energy loss peaks at 91, 102 and 114 meV to the Si-C vibration at the SiC surfaces, the low frequency Fuchs-Kliewer phonon mode and the high-frequency one, respectively. STM images of SiC films on both surfaces show the presence of many islands which surface areas are 10 X 10-35 nm ² . The well characterized SiC films are formed at approximately 900°C on both surfaces.