A polycrystalline-Si/sub 1-x/Ge/sub x/-gate CMOS technology

Abstract

A novel polycrystalline silicon-germanium gate CMOS process has been developed for a submicron CMOS technology. The incorporation of germanium into a heavily doped p-type polycrystalline-silicon (P/sup +/ poly-Si) gate material causes the gate work function to be reduced (more than 300 mV for a 60% Ge material), so that both NMOS and PMOS surface-channel devices may be achieved. In addition, it improves the gate sheet resistance by increasing dopant activation. Poly-Si/sub 1-x/Ge/sub x/ films with Ge mole fractions up to 0.6 were found to be completely compatible with standard VLSI fabrication processes in regard to deposition and patterning techniques, high-temperature chemical and mechanical stability, and electrical stability and uniformity.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>