Yb2O3 Thin Films as a Sensing Membrane for pH-ISFET Application

This paper describes the physical properties and sensing characteristics of Yb 2 O 3 sensing membranes grown on Si(100) substrates by reactive sputtering. The structural and morphological features of these films with annealing at various temperatures were studied by X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy. We found that Yb 2 O 3 films annealed at 800°C exhibit a high sensitivity of 55.5 mV/pH, a low hysteresis voltage of 3.76 mV, and a small drift rate of 1.54 mV/h. The good performance resulting from this annealing condition can be ascribed to the well-crystallized Yb 2 O 3 structure, the thin silica layer, and the large surface roughness.