Thermal Stress Resistance for the Structure of MEMS-Based Silicon Differential Resonant Accelerometer
Jing Zhang, Tianhao Wu, Yudong Liu, Lin Chen, Yan Su
Abstract
Due to material mismatch, silicon differential resonant accelerometers (SDRAs) experience unpredictable thermal stress that is challenging to account for. An SDRA with a stress-isolated frame that is co-faced with the sensitive structural layer is shown in this study. Analytical construction is used to create the stress transmission model of SDRA, which incorporates the equivalent stiffness of a stress-isolated frame. It offers a technique to balance the scale factor of the device with thermal stress resistance. Then, from −40 °C to 85 °C, the proposed SDRA devices’ temperature behavior with and without a stress-isolated frame was examined theoretically, numerically, and experimentally. The measured temperature sensitivities of the device with the stress-isolated structure were around −1.15 Hz/°C, 0.19 mg/°C and 37.23 ppm/°C for the frequency, bias, and scale factors, respectively. The bias instability of the novel device is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.72~\mu \text{g}$ </tex-math></inline-formula> . Under the identical experimental conditions, each of these metrics outperformed the device without stress isolation by one to two orders of magnitude, demonstrating the efficiency of the novel stress-isolated structure.