Effect of Electrode Material on Sensing Performance of MEMS-based Pyroelectric Sensors

MEMS technology is employed to fabricate human infrared sensors on double-sided polished glass substrates.For each device, the sensing layer consists of a thin ZnO film deposited on the lower electrode by RF magnetron sputtering.The top electrode was deposited by an electron beam evaporation method with the same material as that used for the bottom electrode.Numerical and experimental investigations were performed to examine the effects of five different electrode materials (Cr, Cu, Au, Pt, and Ag) on the sensing performance of the fabricated device.The experimental results showed that the use of Ag as the electrode material results in the highest response voltage (23 mV/mW) at a chopping frequency of 60 Hz.Additionally, the simulation results showed that the Ag electrodes yield the fastest temperature response.For all the electrode materials, the temperature-time change rate of the sensing layer was positively correlated with the voltage response of the sensor chip.