Thermal Stress Resistance for the Structure of MEMS-Based Silicon Differential Resonant Accelerometer

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
$0.72~\mu \text{g}$
. 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.