Patent ID: 8659006

Claim:
A nanowire field effect transistor (FET) device, comprising: a semiconductor-on-insulator (SOI) wafer comprising a SOI layer over a buried oxide (BOX), and a plurality of nanowires and pads patterned in the SOI layer wherein the pads are attached at opposite ends of the nanowires in a ladder-like configuration, and wherein the nanowires are suspended over the BOX, and wherein the nanowires patterned in the SOI layer have a pitch comprising at least a first pitch, and at least a second pitch that is different from the first pitch; an interfacial oxide surrounding each of the nanowires; and gate stacks surrounding the nanowires, such that at least a first one of the gate stacks corresponding to at least one first nanowire FET is formed over the nanowires having the first pitch and at least a second one of the gate stacks corresponding to at least one second nanowire FET is formed over the nanowires having the second pitch, each of the gate stacks having (i) a conformal gate dielectric present on the interfacial oxide, surrounding the nanowires (ii) a conformal first gate material on the conformal gate dielectric, surrounding the nanowires (iii) a work function setting material on the conformal first gate material, at least partially surrounding the nanowires, and (iv) a second gate material on the work function setting material, surrounding the nanowires, wherein a volume of the conformal first gate material and a volume of the conformal work function setting material in the gate stacks are proportional to the pitch of the nanowires, wherein the work function setting material is configured to change threshold voltages of the device, and wherein, by way of the volume of the work function setting material in the gate stacks being proportional to the pitch of the nanowires, the first nanowire FET comprising the first one of the gate stacks formed over the nanowires having the first pitch has a different threshold voltage from the second nanowire FET comprising the second one of the gate stacks formed over the nanowires having the second pitch.