Metal oxide semiconductor devices having doped silicon-compromising capping layers and methods for fabricating the same

Methods are provided for forming a semiconductor device comprising a semiconductor substrate. In accordance with an exemplary embodiment, a method comprises the steps of forming a high-k dielectric layer overlying the semiconductor substrate, forming a metal-comprising gate layer overlying the high-k dielectric layer, forming a doped silicon-comprising capping layer overlying the metal-comprising gate layer, and depositing a silicon-comprising gate layer overlying the doped silicon-comprising capping layer.