Co/Si(111) interface: Formation of an initial CoSi2 phase at room temperature

Abstract

Ultrathin films (≲50 monolayers) of Co have been deposited on atomically clean 7×7 Si(111) surfaces at room temperature and characterized by in situ surface techniques such as Auger electron spectroscopy and low-energy electron diffraction. Formation of a boundary CoSi2-like phase is surprisingly found at a very low coverage range (≲4 monolayers) as evidenced by low-temperature transport measurements (resistivity and Hall effect) and also by cross-sectional high-resolution transmission electron microscopy.