High thermal stability metal gate with tunable work function

It has been reported that the work function of Ta-Pt alloys is tunable and Ta-Pt is a possible gate material for CMOS devices. In this work, we demonstrate that the Ta-Pt alloy is thermally stable up to 900 /spl deg/C. The impact of oxygen contamination and thermal stress on the stability of the MOS structure with the alloy gate is also discussed. It is concluded that the Ta-Pt alloy is a good candidate for gate electrode in the nanoscale CMOS regime and is compatible with the conventional self-aligned process.