Transistors with dual work function metal gates by single full silicidation (FUSI) of polysilicon gates

Abstract

Metal gate electrodes with two different work functions, /spl sim/4.5 and /spl sim/4.9 eV for NMOS and PMOS, respectively, were obtained by single-step full silicidation of poly gates. Reduction of polysilicon depletion was /spl sim/0.25 nm. Pile-up of arsenic at the NMOS dielectric is believed responsible for NiSi work function modification. Metal gate may offer little or no gate current reduction for the same T/sub oxinv/ as poly gate.