Design and performance analysis of GAA Schottky barrier-gate stack-dopingless nanowire FET for phosphine gas detection

Abstract

This paper proposed a Gate-All-Around (GAA) Schottky Barrier (SB)-Gate Stack (GS)-based Dopingless Cylindrical Nanowire Field-Effect Transistor (SB-GS-DNWFET) for the application of phosphine (PH3) gas detection. The Schottky barrier nanowire FET is used over a conventional nanowire FET at nanometer scale due to its inherent advantages such as low parasitic resistance and higher ON-state current. In this sensor, the changes in the work function of the metal gate electrode have been used for the detection amount of gas. Three different catalytic metals such as platinum, rhodium, and iridium are preferred as gate electrodes for PH3 gas detection because of their reactivity and sensitivity towards that gas. The sensitivity can be measured in terms of change in ON-state current (ION), subthreshold leakage current (IOFF), ON-state current-to-OFF-state current ratio (ION/IOFF), and threshold voltage (Vth) for sensing the gas molecules. The work function of these catalytic metals at gate electrode is varied as 50, 100, 150, and 200 meV to investigate the change in sensitivity parameters. In this work, the sensitivity of the Schottky barrier GAA-NWFET gas sensor with different catalytic metals (Pt, Rh, Ir) is compared and the impact of process parameters such as channel length and gate stacked (GS = SiO2 + high-k dielectric) on the sensitivity parameters is also studied.