Dual epitaxial process for a finfet device

A method comprising:

• forming a first fin and a second fin extending above a semiconductor substrate, with a shallow trench isolation (STI) region therebetween, and a space defined between the first and second fins above a top surface of the STI region, and a first height between the top surface of the STI region and top surfaces of the first and second fins, the first and second fins having a first longitudinal direction;
• forming a first gate electrode over the first fin, the first gate electrode having a second longitudinal direction normal to the first longitudinal direction;
• depositing a flowable silicon oxide or silicon nitride dielectric material into the space, the dielectric material having a top surface above the top surface of the STI region, so as to define a second height between the top surface of the dielectric material and the top surfaces of the first and second fins, such that the second height is less than the first height;
• and
• epitaxially forming first and second fin extensions above the dielectric, on the first and second fins, respectively, after the depositing step.

A finFET comprising:

• a first fin and a second fin extending above a semiconductor substrate, with a shallow trench isolation (STI) region therebetween, and a space defined between the first and second fins above a top surface of the STI region, the fins having a first longitudinal direction;
• a first gate electrode over the first fin, the first gate electrode having a second longitudinal direction normal to the first longitudinal direction;
• a flowable dielectric material layer on the top surface of the STI region, so as to define a step height between the top surface of the dielectric material and the top surfaces of the first and second fins that is smaller than a distance between the top surface of the STI region and the top surfaces of the first and second fins;
• and
• first and second epitaxial SiGe lateral fin extensions above the dielectric, on the first and second fins, respectively, the fin extensions extending laterally beyond side edges of the fin below a top surface of the dielectric material.