Study of high-k Er2O3 thin layers as ISFET sensitive insulator surface for pH detection

This paper describes the structural and sensing properties of high-k Er2O3 sensing membranes deposited Oil Si Substrates through reactive sputtering. X-ray diffraction, X-ray photoelectron Spectroscopy, and atomic force microscopy were employed to analyze the Structural and morphological features of these films after annealing at various temperatures. Electrolyte-insulator-semiconductor (EIS) devices with a high-k Er2O3 sensing film annealed at 700 C exhibit good sensing characteristics, including a high sensitivity of 57.58 mV/pH in the solutions from pH I to pH 13, a small hysteresis voltage of 6.23 mV in the pH loop 7 -> 4 -> 7 -> 10 -> 7, a low drift rate of 1.75 mV/h in the pH 7 buffer solution. and a high selective responses towards H+. This improvement is attributed to the formation of a thinner silicate layer and the large surface roughness. (C) 2009 Elsevier B.V. All rights reserved.