Improvement of interface structure and magnetic properties of Co on Si (100) by surfactant (Sb) mediated growth

In this study thin Co films were grown on Si (100): (1) with one monolayer of Sb as surfactant and (2) without any surfactant. The Co film, its interface with the Si substrate and the behavior of the Sb surfactant layer were investigated during the growth by high-resolution Rutherford backscattering. By the use of Sb, the evaporated cobalt grows in a layer-by-layer mode and the mixing of Co and Si at the interface is strongly reduced. During the evaporation of Co, Sb floats on the surface for all Co coverages with some incorporation in the grown Co film only for higher coverages. The improvement of the interface quality is also reflected in the magnetic properties of the Co film.