MOSFETs made from GaN nanowires with fully conformal cylindrical gates
Paul T. Blanchard, Kristine A. Bertness, Todd E. Harvey, Aric W. Sanders, Norman A. Sanford, Steven M. George, Dragos Seghete
We report novel metal-oxide-semiconductor field effect transistors (MOSFETs) based on individual gallium nitride (GaN) nanowires with fully conformal cylindrical gates. The W/Al2O3 gates were deposited by atomic layer deposition. Reverse-bias breakdown voltages exceeded the largest gate voltage tested (-35 V). The nanowire MOSFETs showed complete pinchoff, with threshold voltages between -4 and -12 V. Maximum transconductances exceeded 10 υS, and ON/OFF current ratios higher than 108 were measured. Significant gating hysteresis and memory effects were also present, indicative of charge traps. Although further optimization is needed, these results represent a promising step forward in the development of efficient GaN nanowire-based FETs.