Metal gate structure and methods of fabricating thereof

A semiconductor device, comprising:

• a first fin and a second fin extending from a semiconductor substrate, wherein a shallow trench isolation (STI) extends between the first and second fins;
• a first gate structure extending over the first fin and a second gate structure extending over the second fin, the first and second gate structures being collinear, wherein an end of the first gate structure has a curved profile in a top view and an end of the second gate structure has a curved profile in the top view;
• a third gate structure extending over the first fin and a fourth gate structure extending over the second fin, the third and fourth gate structures being collinear;
• and
• a dielectric region interposing the first and the second gate structures and interposing the third and fourth gate structures, wherein the dielectric region extends from the end with the curved profile of the first gate structure to the end with the curved profile of the second gate structure.

A semiconductor device, comprising:

• a first fin and a second fin extending from a semiconductor substrate, wherein a shallow trench isolation (STI) extends between the first and second fins;
• a first gate structure extending over the first fin and a second gate structure extending over the second fin, the first and second gate structures being collinear;
• a third gate structure extending over the first fin and a fourth gate structure extending over the second fin, the third and fourth gate structures being collinear;
• and
• a dielectric region interposing the first gate structure and the second gate structure and interposing the third gate structure and fourth gate structure, wherein the dielectric region has a sidewall having an angle of less than approximately 45 degrees between the first gate structure and the third gate structure.