Ab initio study of metal gate electrode work function

The work function of metal multilayers and monolayers on bulk metals was studied using the first principle pseudopotential method within the local density approximation in order to find a way to modulate the work function of metal gate electrodes. Various multilayer stacks and bilayer stacks of two systems, Al–Pt and Al–Ni, were examined. It was found that two or three layers of the metal are enough to shift the work function to that of the surface metal. Also, it was found that even a submonolayer could affect the work function of the bulk metal significantly.