Effect of annealing on the gate effective work-function modulation for the Al/TiN/SiO2/P-Si structure

In our work, we investigate the effective work function (EWF) modulation of the metal gate about the Al/TiN/SiO₂/p-Si structure through the thermal annealing. Through different annealing temperature and different annealing time, we find the EWF of gate electrode shifts from 4.73 eV (suitable for PMOS) to 4.18 eV (suitable for NMOS). We think the diffusion of Al to the interface and the variation of the thin TiN film characteristic are responsible for the decrease of the EWF.