Techniques for the fabrication of field-effect transistors (FETs) having nanowire channels are provided. In one aspect, a method of fabricating a FET is provided comprising the following steps. A substrate is provided having a silicon-on-insulator (SOI) layer. At least one nanowire is deposited over the SOI layer. A sacrificial gate is formed over the SOI layer so as to cover a portion of the nanowire that forms a channel region. An epitaxial semiconductor material is selectively grown from the SOI layer that covers the nanowire and attaches the nanowire to the SOI layer in a source region and in a drain region. The sacrificial gate is removed. An oxide is formed that divides the SOI layer into at least two electrically isolated sections, one section included in the source region and the other section included in the drain region. A gate dielectric layer is formed over the channel region. A gate is formed over the channel region separated from the nanowire by the gate dielectric layer. A metal-semiconductor alloy is formed over the source and drain regions.