Three dimensional FET devices having different device widths

A method of manufacturing a three dimensional FET device structure comprising:

• providing a substrate having a semiconductor layer on an insulator layer;
• forming a plurality of three dimensional fins in the semiconductor layer;
• applying a masking material to a first plurality of fins while exposing a second plurality of fins;
• applying a hydrogen atmosphere to the substrate and exposed second plurality of fins for a first predetermined time at a first predetermined temperature and pressure, the hydrogen atmosphere causing the exposed second plurality of fins to reflow and change shape while the masked first plurality of fins do not change shape;
• removing the masking material from the first plurality of fins;
• and
• forming a gate to wrap around each of the fins of the first and second plurality of fins, the gate having a longitudinal dimension which is perpendicular to a longitudinal dimension of each of the first and second plurality of fins;
• such that the first and second plurality of fins are formed having a device width being defined as the circumference of the three dimensional fin in contact with its gate and such that the first plurality of fins having a first device width and a second plurality of fins having a second device width with the first device width being different than the second device width.