A method for fabricating a gate electrode structure of a semiconductor device includes the steps of forming a refractory metal layer of such as tungsten over a substrate, a nitride layer of such as tungsten nitride on the refractory metal layer, and a low resistance metal layer of such as gold (Au) on the nitride layer, and etching and removing the portions of the refractory metal layer and the nitride layer that are existing outside a predetermined region. In place of the refractory metal layer, the refractory metal compound layer may be used. The nitride layer is formed by introducing a nitrogen gas into a sputtering system where reactive sputtering is carried out. Without sacrificing the reliability of the gate or barrier characteristics, it is possible to reduce the number of process steps otherwise required.