Characteristics of Dual Polymetal (W/WNx/Poly-Si) Gate Complementary Metal Oxide Semiconductor for 0.1 µm Dynamic Random Access Memory Technology

Abstract

We developed a dual polymetal (W/WNx/poly-Si) gate complementary metal oxide semiconductor (MOS) down to a 0.15 µm gate length. The short-channel effects are effectively suppressed and a saturation current of 300 µA/µm is obtained for nMOS and 110 µA/µm is observed for pMOS at a 0.15 µm gate length. The lower saturation current of pMOS is attributed both to the p+-doped poly gate depletion and to the hole mobility degradation due to the increased vertical electric field in the surface-channel pMOS. Boron penetration is not observed with pure SiO2 gate dielectrics. The gate induced drain leakage current could be markedly reduced by optimizing the well doping below the gate edge.