Semiconductor structure

A semiconductor structure comprising:

• a fin structure comprising:
• an outer portion comprising a semiconductor material;
• and
• an inner portion inside the outer portion and comprising the semiconductor material;
• a high-k dielectric layer over the fin structure;
• a dielectric layer between the high-k dielectric layer and the fin structure;
• and
• a metal gate electrode over the high-k dielectric layer,
• wherein a concentration of the semiconductor material in the outer portion is less than a concentration of the semiconductor material in the inner portion.

A semiconductor structure comprising:

• a first fin structure and a second fin structure, wherein the first fin structure comprises a first semiconductor material, and the second fin structure comprises the first semiconductor material and a second semiconductor material;
• a high-k dielectric layer over the first fin structure and the second fin structure;
• a first dielectric layer between the high-k dielectric layer and first fin structure, and a second dielectric layer between the high-k dielectric layer and the second fin structure;
• and
• a first metal gate electrode over the high-k dielectric layer and a second metal gate electrode over the high-k dielectric layer,
• wherein the second fin structure further comprises an outer portion and an inner portion inside the outer portion, and a concentration of the second semiconductor material in the outer portion is less than a concentration of the second semiconductor material in the inner portion.