Low resistance replacement metal gate structure

摘要

A first sacrificial gate structure of a first width and a second sacrificial gate structure of a second width greater than the first width are provided on a semiconductor material portion. A dielectric spacer and a planarizing dielectric material are provided surrounding each sacrificial gate structure. Each sacrificial gate structure is then removed forming gate cavities. A high k dielectric material, a metal nitride hard mask and a physical vapor deposited (PVD) amorphous-silicon cap are provided. Vertical portions of the metal nitride hard mask and the high k dielectric material are removed from a portion of each gate cavity. Additional PVD amorphous silicon is then deposited and then all amorphous silicon and remaining metal nitride hard mask portions are removed. A work function portion having a stair-like surface, a diffusion barrier portion, a conductive metal structure and a dielectric cap are then formed into to each of the gate cavities.

主权项

1. A semiconductor structure comprising:
a first functional gate structure of a first width and located on a surface of a semiconductor material portion, said first functional gate structure comprising, from bottom to top, a first high k gate dielectric material portion, a first workfunction metal portion having a stair-like surface profile, a first diffusion barrier portion, a first metal structure and a first dielectric cap; a second functional gate structure of a second width that is greater than said first width and located on another surface of said semiconductor material portion, said second functional gate structure comprising, from bottom to top, a second high k gate dielectric material portion, a second workfunction metal portion having a stair-like surface profile, a second diffusion barrier portion, a second metal structure and a second dielectric cap; a dielectric spacer located on each sidewall surface of said first and said second functional gate structures; and a planarizing dielectric material located adjacent said dielectric spacer, wherein a topmost surface of said planarizing dielectric material is coplanar with a topmost surface of said first and said second dielectric caps.