Abstract: This paper investigates the work function adjustment of a full silicidation (Ni-FUSI) metal gate.It is found that implanting dopant into poly-Si before silicidation can modulate the work function of a Ni-FUSI metal gate efficiently.With the implantation of p-type or n-type dopants,such as BF2,As,and P,the work function of a Ni-FUSI metal gate can be made higher or lower to satisfy the requirement of pMOS or nMOS,respectively.But implanting a high dose of As into a poly-Si gate before silicidation will cause the delamination effect and EOT loss,and thus As dopant is not suitable to be used to adjust the work function of a Ni-FUSI metal gate.Due to the EOT reduction in the FUSI process,the gate leakage current of a FUSI metal gate capacitor is larger than that of a poly-Si gate capacitor.

Key words: metal gate, FUSI, silicide