Multiple fin heights for effective width tuning

A semiconductor structure comprising:

• a substrate comprising an n-type region and a p-type region;
• a first fin formed over the n-type region of the substrate;
• a second fin formed over the p-type region of the substrate;
• a first bottom dielectric isolation (BDI) region positioned directly between the first fin and the n-type region of the substrate;
• and
• a second BDI region positioned directly between the second fin and the p-type region of the substrate, wherein a height of the second BDI region is different than a height of the first BDI region, thereby providing the first fin having a first effective width and the second fin having a second effective width different than the first effective width.

A semiconductor structure comprising:

• a plurality of fins formed over a substrate, the plurality of fins comprising a first fin comprising a first height, a second fin comprising a second height different than the first height, and a third fin comprising a third height different than the first height and the second height;
• a gate formed over the first fin, the second fin, and the third fin;
• a first bottom dielectric isolation (BDI) region positioned directly between the first fin and the substrate;
• a second BDI region positioned directly between the second fin and the substrate;
• and
• a third BDI region positioned directly between the third fin and the substrate;
• wherein an effective width of the first fin is less than an effective width of the second fin and the effective width of the second fin is less than an effective width of the third fin.

A method for forming a semiconductor device, the method comprising:

• forming a first shallow trench isolation (STI) region over a first portion of a substrate;
• forming a second STI region over a second portion of the substrate, wherein a topmost surface of the second STI region is coplanar to a topmost surface of the first STI region;
• forming a first fin in and above the first STI region;
• forming a second fin in and above the second STI region, wherein a topmost surface of the second fin is coplanar to a topmost surface of the first fin;
• and
• forming a bottom dielectric isolation (BDI) region directly between the first fin and the substrate, thereby providing the first fin having a first effective width and the second fin having a second effective width different than the first effective width.

A method for forming a semiconductor device, the method comprising:

• forming a substrate comprising an n-type region and a p-type region;
• forming a first fin over the n-type region of the substrate;
• forming a second fin over the p-type region of the substrate;
• forming a first bottom dielectric isolation (BDI) region directly between the first fin and the n-type region of the substrate;
• and
• forming a second BDI region directly between the second fin and the p-type region of the substrate, wherein a height of the second BDI region is different than a height of the first BDI region, thereby providing the first fin having a first effective width and the second fin having a second effective width different than the first effective width.