Impact of postdeposition annealing on the sensing and impedance characteristics of TbYxOy electrolyte–insulator–semiconductor pH sensors

Abstract

In this investigation, we explored the impact of postdeposition annealing (PDA) on the sensing and impedance characteristics of TbY_xO_y sensing films deposited on Si(100) substrates through reactive cosputtering for electrolyte–insulator–semiconductor (EIS) pH sensors. The TbY_xO_y EIS sensor annealed at 800 °C exhibited the best sensing characteristics (pH sensitivity, hysteresis voltage, and drift rate). In addition, the effect of PDA treatment on the impedance properties of TbY_xO_y EIS sensors was studied using the capacitance–voltage method. The resistance and capacitance of TbY_xO_y sensing films were determined using different frequency ranges in accumulation, depletion, and inversion regions. In our impedance spectroscopy analysis, the semicircle diameter of the TbY_xO_y EIS sensor became smaller, due to a gradual decrease in the bulk resistance of the device, as the PDA temperature was increased.