Thermal stability of ultra-thin CoSi, films on Si(lOO)-2 X 1 surfaces

The thermal stability of epitaxial Co disilicide on Si(100) substrates has been investigated by coaxial impact-collision ion scattering spectroscopy (CAICISS), scanning tunneling microscopy @TM) and scanning tunneling spectroscopy (STS). After the Co deposition of 1 ML on Si(lOO)-2 X 1 clean surfaces and the subsequent annealing at 540°C for 10 min, CoSi,(llO) islands are formed on Si(100) and the island surfaces are covered with Si layers with a thickness of about 0.4 nm. For the 3 ML Co deposition, atomically flat and pinhole-free epitaxial CoSi,(lOO)-(fi X fi)R45 films on Si(100) are obtained, whose surfaces are not covered with additional Si layers. The CoSi,(l 10) islands and the CoSi,(lOO) films are dissolved into Si substrates by thermal annealing above 600°C.