OXIDATION OF GD THIN-FILMS ON SI SUBSTRATES VIA GRAIN-BOUNDARIES

The low-temperature oxidation of Gd thin films evaporated on Si substrates and the role of Si native oxide at the interface of Gd silicide growth have been investigated by x-ray diffraction, XPS and RBS. The Gd layer is extremely reactive towards oxygen and is quickly oxidized in air. Its reactivity can be diminished by introducing a small quantity of Si into the Gd film. In the initial stage Si is accumulated mainly at the grain boundaries of the Gd film, thereby blocking the main oxygen diffusion path and preventing Gd2O3 formation. If Si native oxide is initially present, at low temperature the growth of Gd silicide is slowed down but at high temperature Si/SiO2/Gd is may transformed to Gd2O3.