Gate First Metal-Aluminum-Nitride PMOS Electrodes for 32nm Low Standby Power Applications

The effective work function (EWF) of ternary metal-aluminum-nitride (M-Al-N, M=Ta, Ti, Mo, W) metal gate electrodes in high-k dielectric gate stacks has been investigated. With the addition of Al, the EWF can be tuned toward p-type (~5 eV) by 250 meV compared to the EWF of the binary metal nitride. Low threshold voltage (V_t) of ~ -0.35 V, an equivalent oxide thickness (EOT)~1.2 nm, and performance suitable for gate-first 32 nm low standby power applications are demonstrated.