Semiconductor Device Structure Having a Plurality of Threshold Voltages and Method of Forming the Same

A semiconductor structure, comprising:

• a first fin structure and a second fin structure over a first region of a substrate;
• a third fin structure over a second region of the substrate;
• a gate dielectric layer over the first fin structure, the second fin structure, and the third fin structure;
• a work function layer selectively disposed over the first fin structure and the second fin structure;
• and
• a gate electrode layer over the first fin structure, the second fin structure, and the third fin structure,
• wherein the first fin structure comprises a uniform germanium concentration,
• wherein the second fin structure comprises a germanium concentration profile from a surface of the second fin structure to a diffusion depth from the surface of the second fin structure,
• wherein the third fin structure is substantially free of germanium.

A semiconductor structure, comprising:

• a first fin structure and a second fin structure over a first region of a substrate;
• a first dielectric fin between the first fin structure and the second fin structure;
• a third fin structure over a second region of the substrate;
• a second dielectric fin between the second fin structure and the third fin structure;
• and
• a gate structure over the first fin structure, the second fin structure, the first dielectric fin, the third fin structure, and the second dielectric fin,
• wherein the first fin structure comprises a first strained channel region,
• wherein the second fin structure comprises a second strain channel region,
• wherein the first strained channel region comprises a homogeneous germanium concentration,
• wherein the second strained channel region comprises a germanium concentration profile from a surface of the second fin structure to a diffusion depth from the surface of the second fin structure,
• wherein the third fin structure is substantially free of germanium.