A plurality of semiconductor fins is formed on a surface of an insulator layer. Gate structures are then formed that are orientated perpendicular and straddle each semiconductor fin. A dielectric spacer is then formed on vertical sidewalls of each gate structure. Next, an etch is performed that removes exposed portions of each semiconductor fin and a portion of the insulator layer not protected by the dielectric spacers and the gate structures. The etch provides semiconductor fin portions that have exposed vertical sidewalls. A doped semiconductor material is then formed from each exposed vertical sidewall of each semiconductor fin portion, followed by an anneal which causes diffusion of dopants from the doped semiconductor material into each semiconductor fin portion and the formation of source/drain regions. The source/drain regions are present along the sidewalls of each semiconductor fin portion and are located beneath the dielectric spacers.