Substrate isolated VTFET devices

A method of forming vertical transport field effect transistor (VTFET) devices is provided. The method includes forming a plurality of vertical fins on an upper insulating layer of a dual insulator layer semiconductor-on-insulator (SeOI) substrate, and forming two masking blocks on the plurality of vertical fins, wherein a portion of a protective layer and a fin template on each of the plurality of vertical fins is exposed between the two masking blocks. The method further includes removing a portion of the upper insulating layer between the two masking blocks to form a first cavity beneath the plurality of vertical fins, and forming a first bottom source/drain in the first cavity below the plurality of vertical fins. The method further includes replacing the two masking blocks with a masking layer patterned to have two mask openings above portions of the upper insulating layer adjacent to the first bottom source/drain.