A method of forming fin field effect devices is provided. The method includes forming a plurality of vertical fins on a substrate. The method further includes forming a dielectric pillar on the substrate between two adjacent vertical fins, wherein at least one of the vertical fins is on a first region of the substrate, and at least one of the vertical fins is on a second region of the substrate. The method further includes growing a bottom source/drain layer on the first region of the substrate and the second region of the substrate. The method further includes depositing a bottom spacer layer on the bottom source/drain layer, and a filler layer on the bottom spacer layer. The method further includes forming a cover block on the first region of the substrate, and removing the portion of the filler layer on the second region of the substrate.