Heterostructure Barriers in Wrap Gated Nanowire FETs

Abstract

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 InAs <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.8</sub> P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.2</sub> 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.