Semiconductor device and method of manufacturing the same

A method of manufacturing a gate structure for a semiconductor device, comprising:

• providing a substrate having a first region, a second region, and a third region;
• forming a first gate structure having a first work function layer over the first region for a first fin-type field effect transistor (FinFET);
• forming a second gate structure having a second work function layer over the second region for a second FinFET;
• and
• forming a third gate structure having a third work function layer over the third region for a third FinFET, wherein the first, second, and third work function layers have different thicknesses,
• wherein one of the first, second, and third work function layers is doped with a dopant in a base material by an atomic layer deposition (ALD) method, and the dopant comprises Al, Ta, W or a combination thereof.

A semiconductor device, comprising:

• a first n-type FinFET with a threshold voltage Vn1 comprising a first gate structure, and the first gate structure comprising a first work function layer;
• a second n-type FinFET with a threshold voltage Vn2 comprising a second gate structure, and the second gate structure comprising a second work function layer;
• a third n-type FinFET with a threshold voltage Vn3 comprising a third gate structure, and the third gate structure comprising a third work function layer;
• a first p-type FinFET with a threshold voltage Vp1 comprising a fourth gate structure, and the fourth gate structure comprising a fourth work function layer;
• a second p-type FinFET with a threshold voltage Vp2 comprising a fifth gate structure and, and the fifth gate structure comprising a fifth work function layer;
• and
• a third p-type FinFET with a threshold voltage Vp3 comprising a sixth gate structure and, the sixth gate structure comprising a sixth work function layer, wherein:
• Vn1<Vn2<Vn3 and Vp1<Vp2<Vp3,
• at least one of the second work function layer, the third work function layer, the fourth work function layer, the fifth work function layer, and the sixth work function layer comprises a base material and a dopant doped in the base material, wherein the dopant comprises Al, Ta, W, or a combination thereof.