Fabrication and characterization of pre-aligned gallium nitride nanowire field-effecttransistors

Abstract

We report on the fabrication of gallium nitride (GaN) nanowire field-effect transistors(FETs) with both bottom-gate and top-gate structures, with very high yield using a uniquepre-alignment process. The catalyst positions were chosen to be aligned with thesource/drain position, and Ni catalysts with a diameter of 200 nm were deposited selectivelyat these pre-determined positions. Electrostatic analysis was performed for the bottom-gatedevices to estimate the nanowire’s electrical characteristics. Comparison of the bottom-gateand the top-gate structures indicated that better performance, in terms of saturation andbreakdown characteristics, can be obtained using the top-gate structure. For the top-gatenanowire FETs, temperature-dependent characteristics were investigated up to thecurrent saturation regime, and memory effects were observed at room temperature.