Vertical field-effect transistor (VFET) devices and methods of forming VFET devices are provided. The methods may include forming a preliminary VFET on a substrate. The preliminary VFET may include a bottom source/drain region on the substrate, a channel region on the bottom source/drain region, a top source/drain region on the channel region, a patterned sacrificial layer on a side surface of the channel region, and an insulating layer. The top source/drain region and the patterned sacrificial layer may be enclosed by the insulating layer. The methods may also include forming a contact opening extending through the insulating layer and exposing a portion of the patterned sacrificial layer, forming a cavity between the channel region and the insulating layer by removing the patterned sacrificial layer through the contact opening, and forming a gate electrode in the cavity.