A method of fabricating a gate electrode for a semiconductor comprising the steps of: providing a substrate; providing on the substrate a layer of a first material of thickness t.sub.p, the first material being selected from the group consisting of Si, Si.sub.1-x--Ge.sub.x alloy, Ge and mixtures thereof and a layer of metal of thickness t.sub.m; and annealing the layers, such that substantially all of the first material and the metal are consumed during reaction with one another.