A method comprising: forming a substrate; forming a first nanowire over the substrate; forming a second nanowire over the substrate; forming a gate over a portion of the first and second nanowires; implanting a dopant such that a region between the first and second nanowires under the gate does not receive the dopant while a region between the first and second nanowires away from the gate receives the dopant, wherein the dopant amorphize a material of the region between the first and second nanowires away from the gate; and isotopically etching of the region between the first and second nanowires away from the gate.