Method of forming germanium doped polycrystalline silicon gate of mos transistor and method of forming cmos transistor device using the same

Abstract

A method of forming polycrystalline silicon germanium gate electrode is disclosed. The method include the steps of forming gate insulation layer on a substrate, forming a polycrystalline silicon layer on the gate insulation layer and making a plasma doping of germanium to the polycrystalline silicon layer. Generally, boron is doped to the polycrystalline silicon after the step of the plasma doping of germanium. The process of plasma doping of germanium comprises the step of forming germanium contained plasma and enhancing bias electric potential to substrate for the formulated germanium plasma to be accelerated and injected to the polycrystalline silicon layer revealed. If the present invention is applied to CMOS transistor device, doping mask for the germanium plasma doping can be used.