Ex situ formation of oxide-interlayer-mediated-epitaxial CoSi2 film using Ti capping

Abstract

A modified oxide mediated epitaxy process using a single deposition and ex situ annealing by Ti capping has been developed in this study. With pure Co on Shiraki oxide, the reaction between Co and Si did not occur even at 800 °C during ex situ annealing, because of the adsorption of oxygen on the Co film. However, when the pure Co on the Shiraki oxide was capped by Ti, a uniform Ti oxide surface layer was formed during the initial stage of annealing, which had a role to eliminate the adsorption of oxygen on the Co film. It led to uniform Co diffusion into the Si substrate through the Shiraki oxide, resulting in epitaxial ${\mathrm{CoSi}}_{\mathrm{2}}.$ A good channeling ${\chi }_{\min }$ value of 18% comparable to that of the Ti/Co bilayer system was measured in the epitaxial ${\mathrm{CoSi}}_{\mathrm{2}}$ formed from this modified oxide mediated epitaxy process.