A study of the design of ZnO thin film pressure sensors

Abstract

This study takes the first step in designing ZnO thin film pressure sensors with high operating temperatures. To fabricate the pressure sensors, ZnO thin films are deposited on SiO₂/(100)Si substrates to obtain structures similar to those of silicon-on-insulator. The optimal deposition parameters used to deposit the thin films are a full width at half maximum (FWHM) of 0.269, a c-axis-oriented structure near 100% and an average grain size of 321 Å. Here, to simplify the ZnO thin film pressure sensor system, a new parameter, the ZnO resistance, which changes with the change of pressure, is analysed. ZnO thin film fabricated under the optimal conditions can work as a pressure sensor and its response value, which is proportional to pressure, is greater than 8mΩ/psi. The relative pressure can be obtained from the difference between the response value before applying pressure and after. Further, a special characteristic of these ZnO pressure sensors is that the pressure can be read even during gas inlet.