a-ITZO based thin film transistor for ammonia gas sensing: a simulation study

Abstract This work is an optimization study by numerical simulation of the performance of amorphous indium tin zinc oxide thin film transistor (a-ITZO TFT) based gas sensor using SILVACO-ATLAS software. The optimization process is focused on the catalytic source/drain electrode, dielectric material and work-function difference. Based on simulation results, when the electrode material is switched from cobalt to molybdenum, the value of drain current was found to be increased from 39 μA to 231 μA. For molybdenum, ruthenium and cobalt with a work function difference of 200 meV, the OFF state current sensitivity (SIOFF) and ON State current sensitivity (SION) values were found to be 607.27 and 213.2, 102.81 and 0.35 and 0.015 and 0.90 respectively. An increase in the sensitivity of simulated structure was observed with the value of work function difference that indicates an increase in the concentration of gas. The impact of the dielectric material also reveals that high-k dielectric materials boost the sensitivity of the proposed device. The simulation results confirm the a-ITZO TFTs potential in gas sensing applications.