Impact of yttrium content and thermal annealing on the structural and sensing characteristics of YbYxOy sensing membranes

Abstract

In this paper, we explore the impact of yttrium content and thermal annealing on the structural properties and sensing characteristics of YbYxOy sensing membranes deposited on Si substrates through reactive cosputtering for electrolyte-insulator-semiconductor (EIS) pH sensors. X-ray photoelectron spectroscopy and atomic force microscopy were used to study the compositional and morphological features of these membranes as functions of the growth conditions (Y plasma powers of 50, 100, and 150 W; temperatures ranging from 700 to 900 °C). The YbYxOy EIS device prepared under an Y plasma power of 100 W with subsequent annealing at 800 °C exhibited the best sensing characteristics (pH sensitivity, hysteresis voltage, and drift rate). We attribute this behavior to the optimal yttrium content in this sensing membrane improving the stoichiometry of YbYxOy membrane and its surface roughness.