In this study, we report on an electrolyte-insulator-semiconductor (EIS) device with a novel high-k Dy2TiO5 sensing membranes deposited on Si substrates through reactive cosputtering method. The effect of thermal annealing (700, 800, and 900 degrees C) on the structural and surface properties of Dy2TiO5 sensing membrane was investigated by x-ray diffraction, x-ray photoelectron spectroscopy, and atomic force microscopy. The EIS device incorporating a Dy2TiO5 sensing film that had been annealed at 800 degrees C exhibited good sensing characteristics, including a high sensitivity (57.59 mV/pH in solutions from pH 2-12), a small hysteresis voltage (0.2 mV in the pH loop 7 -> 4 -> 7 -> 10 -> 7),and a low drift rate (0.362 mV/h in the buffer solution at pH 7). This improvement can be attributed to the small number of crystal defects and the large surface roughness. Furthermore, a hybrid configuration of the Dy2TiO5 membrane-EIS with urease-immobilized film was prepared by the entrapment of enzyme molecules in alginate hydrogel and was demonstrated for urea biosensing. Results demonstrated that the Dy2TiO5 EIS biosensor was able to detect urea with good linearity (R-2 = 0.99) and reasonable sensitivity of 118.38 mV/pC(urea) in the urea concentration range of 1-32 mM. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3547723] All rights reserved.