A gate electrode structure is provided, which includes, from bottom to top, an optional, yet preferred metallic layer, a Ge rich-containing layer and a Si rich-containing layer. The sidewalls of the Ge rich-containing layer include a surface passivation layer. The inventive gate electrode structure serves as a low-temperature electrically activated gate electrode of a MOSFET in which the materials thereof as well as the method of fabricating the same are compatible with existing MOSFET fabrication techniques. The inventive gate electrode structure is electrically activated at low processing temperatures (on the order of less than 750° C.). Additionally, the inventive gate electrode structure also minimizes gate-depletion effects, does not contaminate a standard MOS fabrication facility and has sufficiently low reactivity of the exposed surfaces that renders such a gate electrode structure compatible with conventional MOSFET processing steps.