Increasing ion/ioff ratio in finfets and nano-wires

Abstract

Roughly described, an integrated circuit transistor structure has a body of semiconductor material, the body having two longitudinally spaced doped source/drain volumes with a channel between, a gate stack disposed outside the body and facing at least one of the surfaces of the body along the channel. The body contains an adjustment volume, longitudinally within the channel volume and spaced behind the first surface by a first distance and spaced longitudinally from both the source/drain volumes. The adjustment volume comprises an adjustment volume material having, at each longitudinal position, an electrical conductivity which differs from that of the adjacent body material at the same longitudinal position, at least while the transistor is in an off-state. In one embodiment the adjustment volume material is a dielectric. In another embodiment the adjustment volume material is an electrical conductor.