Humidity Sensors on Thermally Oxidized Silicon Substrates

In recent years, as a ceramic semiconducting material, zinc oxide (ZnO) has received great attention in sensing applications, including ultra-violet (UV), gas, and humidity sensors. In this work, ZnO based humidity sensors were fabricated on thermally oxidized silicon substrates. The contact electrodes for the sensors were realized using patterned aluminium (Al) films. ZnO films were deposited on the substrates as the active layer for the sensors using radio frequency (RF) magnetron sputtering technique. The electrical properties of the sensors were tested in various relative humidity (RH) levels. The ZnO humidity sensors have showed a decrease in resistance with increasing humidity level. The fabrication process and the characteristics of the ZnO humidity sensors will be revealed in this work.