Investigation of work function adjustments by electric dipole formation at the gate/oxide interface in preimplanted NiSi fully silicided metal gates

摘要

The work function adjustments by implanted dopants (P, As, and Sb) in NiSi fully silicided metal gates were investigated. It was found that the work function adjustments only occurred when dopants were segregated at the silicide/dielectric interface after the fully silicided process. The dopant specie, size, and peak concentration at the interface were found to have impacts on work function tuning. The theoretical estimates of work function tuning were calculated using electric dipole domination assumption and confirmed by experimental measurements.