Dual work function metal gate CMOS transistors fabricated by Ni-Ti interdiffusion

A novel CMOS metal gate technology which uses a combination of two metals to achieve low and symmetrical threshold voltages for n- and p-channel devices is demonstrated. One of the gate electrodes is formed by metal interdiffusion, to avoid exposing the gate dielectric to a metal etch process. This approach preserves the uniformity and integrity of the delicate thin gate dielectric.