Analysis of performances of MEMS infrared sensor based on piezoelectric bending resonators

There is a great desire for high-performance and low-cost uncooled infrared (IR) detectors that can survive in harsh environments. To address this need, we are investigating the use of MEMS piezoelectric resonator technology using Aluminum Nitride (AlN) films as a resonating detector. A novel design of an AlN IR sensor based on piezoelectric bending resonator was analyzed and showed that the piezoelectric resonators have the potential to be used as a core element for highly sensitive, low-noise, and low-power uncooled IR detectors [1]. A critical feature of the design that determines the sensing resolution is the minimization of the various loss mechanisms of the resonator. A major loss mechanism for a non-vacuum packaged chip is the acoustic radiation loss in Earth's atmosphere (1 atm) due to the large stroke of the bending resonators. The acoustic radiation loss is the dominant Q limiting mechanism. We propose the use of perforated plates for the bending resonators in order to reduce acoustic radiation loss. The effectiveness of the loss reduction and the performances of the resonant IR sensors are analyzed using finite element simulations. The results are encouraging for the application of these types of IR sensors under the Earth surface atmosphere conditions.