Semiconductor devices are fabricated with vertical field effect transistor (FET) devices having uniform structural profiles. Semiconductor fabrication methods for vertical FET devices implement a process flow to fabricate dummy fins within isolation regions to enable the formation of vertical FET devices with uniform structural profiles within device regions. Sacrificial semiconductor fins are formed in the isolation regions concurrently with semiconductor fins in the device regions, to minimize/eliminate micro-loading effects from an etch process used for fin patterning and, thereby, form uniform profile semiconductor fins. The sacrificial semiconductor fins within the isolation regions also serve to minimize/eliminate non-uniform topography and micro-loading effects when planarizing and recessing conductive gate layers and, thereby. form conductive gate structures for vertical FET devices with uniform gate lengths in the device regions. The sacrificial semiconductor fins are subsequently removed and replaced with insulating material to form the dummy fins.