FORMATION OF METAL GATE ELECTRODE USING RARE EARTH ALLOY INCORPORATED INTO MID GAP METAL

摘要

Semiconductor devices and fabrication methods are provided, in which metal transistor gates are provided for MOS transistors. A rare earth-rare earth alloy incorporated metal nitride layer is formed above a gate dielectric. This process provides adjustment of the gate electrode work function, thereby tuning the threshold voltage of the resulting NMOS transistors.