Effect of parasitic capacitances on impedance measurements in microsensors structures: a numerical study

Abstract

The use of solid electrolyte cells to detect specific gases is widely applied in the electronic control systems. Ionic conduction in this type of sensors is normally studied through impedance spectroscopy, since the data obtained with this technique provide valuable information about the electrical properties of the solid electrolyte and electrode behavior. This work addresses the influence of inter-electrode capacitance on the impedance characterization of small structures. Parasitic capacitance was determined by solving Laplace equation and integrating the potential over a Gauss surface including the electrode. Computer simulations of electrode impedance behavior of a solid cell were carried out using a well-known electronic simulator. It is concluded that parasitic capacitances introduce a small distortion on the high-frequency portions of Nyquist plot that are important when miniaturized sensor are electrically characterized.