Metal High-K Transistor Having Silicon Sidewall For Reduced Parasitic Capacitance, And Process To Fabricate Same

摘要

A method is disclosed to reduce parasitic capacitance in a metal high dielectric constant (MHK) transistor. The method includes forming a MHK gate stack upon a substrate, the MHK gate stack having a bottom layer of high dielectric constant material, a middle layer of metal, and a top layer of one of amorphous silicon or polycrystalline silicon. The method further forms a depleted sidewall layer on sidewalls of the MHK gate stack so as to overlie the middle layer and the top layer, and not the bottom layer. The depleted sidewall layer is one of amorphous silicon or polycrystalline silicon. The method further forms an offset spacer layer over the depleted sidewall layer and over exposed surfaces of the bottom layer.