A vertical field effect transistor includes a first epitaxial region in contact with a top surface of a channel fin extending vertically from a bottom source/drain located above a substrate, a second epitaxial region above the first epitaxial region having a horizontal thickness that is larger than a horizontal thickness of the first epitaxial region. The first epitaxial region and the second epitaxial region form a top source/drain region of the semiconductor structure. The first epitaxial region has a first doping concentration and the second epitaxial region has a second doping concentration that is lower than the first doping concentration. A top spacer, adjacent to the first epitaxial region and the second epitaxial region, is in contact with a top surface of a high-k metal gate stack located around the channel fin and in contact with a top surface of a first dielectric layer disposed between adjacent channel fins.