Numerical Simulation of Dielectric Modulated Cylindrical Schottky Nanowire FETs for Enhanced Analog Performance

Abstract

This paper investigates the performance metrics of Schottky Barrier-based cylindrical nanowire FET and their potential as biosensors through comprehensive gate oxide material engineering. By analyzing high- k dielectric materials such as Al 2 O 3 , HfO 2 , and TiO 2 as replacements for conventional SiO 2 , this study beautifully addresses the challenge of increased gate leakage current due to electron tunneling in thinner SiO 2 layers with transistor scaling. Using the Atlas SILVACO TCAD device simulator, key device parameters are analyzed here, including total gate capacitance, transconductance, maximum transducer power gain, unilateral power gain, threshold voltage, cut-off frequency, and the variation of drain current with gate and drain voltages. Al 2 O 3 , HfO 2 , and TiO 2 show around 11.52%, 17.96% and 18.35% improvement for subthreshold swing and 0.7374 dB, 6.1179 dB and 7.4055 dB improvement for unilateral power gain over SiO 2 . The biosensor equivalent shows 33.7 mV (considering threshold voltage as the sensing metric) and 6.64 mV decade −1 (considering subthreshold swing as the sensing metric) sensitivity enhancement when SiO 2 is replaced with TiO 2 for Keratin. The findings indicate that high permittivity dielectric materials offer superior characteristics for most analog performance parameters due to the enhanced gate control, reduced leakage current, and higher breakdown voltage, thus mitigating scaling issues and enhancing device performance. However, trade-offs exist, as TiO 2 shows higher gate capacitance and lower maximum transducer power gain that can limit its performance in certain analog and digital applications. Hence, this paper investigates the importance of selection of dielectric material in controlling the analog performance parameters of nanowire FET.