Heterostructure Barriers in Wrap Gated Nanowire FETs

We present results on the effects of inserting a heterostructure barrier along the channel of vertical wrapped insulator-gate field-effect transistors (WIGFETs). Two sets of devices were fabricated, one InAs WIGFET and one with a 50-nm-long $hbox{InAs}_{0.8}hbox{P}_{0.2}$ segment in the channel. This addition of P induces a barrier in the conduction band of 130 mV, measured from the Fermi-level. The barrier blocks the diffusion current through the channel and reduces the feedback gating of holes created from band-to-band tunneling, resulting in improvements in on/off current ratio, and subthreshold characteristics. The heterosegment also induces a shift in the threshold voltage and provides an additional parameter for threshold voltage control in nanowire III–V MOSFETs.