Patent ID: 8853788

Claim:
A semiconductor structure comprising: a planarization dielectric layer having a planar topmost surface and located on a semiconductor substrate; a first gate stack comprising: a U-shaped gate dielectric located on a bottom and sidewalls of a first gate cavity laterally surrounded by said planarization dielectric layer and located in a first device region of said semiconductor substrate; a first planar work function material portion comprising a first metallic material having a first work function and present on a horizontal portion of said U-shaped gate dielectric; a second planar work function material portion present on said first planar work function material portion, said second planar work function material portion comprising a second metallic material having a second work function different from said first metallic material and having a topmost surface that is recessed from said planar topmost surface of said planarization dielectric layer; and a metal portion present on said topmost surface of said second planar work function material portion, said metal portion having a top surface that is coplanar with said planar topmost surface of said planarization dielectric layer; and a second gate stack comprising: another U-shaped gate dielectric located on a bottom and sidewalls of a second gate cavity laterally surrounded by said planarization dielectric layer and located in a second device region of said semiconductor substrate; another second planar work function material portion present on a horizontal portion of said another U-shaped gate dielectric, said another second planar work function material portion having a topmost surface that is recessed from said planar topmost surface of said planarization dielectric layer, and another metal portion present on said topmost surface of said another second planar work function material portion, said another metal portion having a top surface that is coplanar with said planar topmost surface of said planarization dielectric layer.