Gate strain induced work function engineering

A semiconductor structure comprising a first p-type field effect transistor (PFET), a first n-type field effect transistor (NFET), a second PFET, and a second NFET located on a substrate, wherein said first PFET and said first NFET comprise a first workfunction material portion overlying a channel of said first PFET and a channel of said first NFET and a first gate conductor material layer applying a first stress to said first workfunction material portion, and said second PFET and said second NFET comprise a second workfunction material portion overlying a channel of said second PFET and a channel of said second NFET and a second gate conductor material layer applying a second stress that is different from said first stress to said second workfunction material portion, wherein said first workfunction material portion is under a first strain due to said first stress and said second workfunction material portion is under a second strain due to said second stress, and said first and second workfunction material portions have a same composition and a same thickness, and said first strain and said second strain shift workfunctions of said first and second workfunction material portions differently.

A semiconductor structure comprising:

• a first field effect transistor including a first semiconductor material portion, a first stack of a first portion of a gate dielectric layer and a first workfunction material portion located over said first semiconductor material portion, and a first gate conductor material layer applying a first stress to said first workfunction material portion, wherein said first workfunction material portion is under a first strain due to said first stress;
• and
• a second field effect transistor including a second semiconductor material portion, a second stack of a second portion of said gate dielectric layer and a second workfunction material portion located over said second semiconductor material portion, a second gate conductor material layer applying a second stress that is different from said first stress to said second workfunction material portion, wherein said second workfunction material portion is under a second strain due to said second stress, and said first strain and said second strain shift workfunctions of said first and second workfunction material portions differently, wherein one of said first and second gate conductor material layers comprises a first metallic material, and another of said first and second gate conductor material layers comprises a second metallic material different from said first metallic material.