A vertical transport field-effect transistor includes gate metal protected by a conformal encapsulation layer. Techniques for fabricating the transistor include depositing the conformal encapsulation layer over the gate metal prior to depositing an additional encapsulation layer such as a nitride layer. The conformal encapsulation layer protects the gate metal during deposition of the additional encapsulation layer, thereby avoiding oxidation or nitridation of the gate metal. The conformal encapsulation layer may be an amorphous silicon layer deposited at relatively low temperature.