Sensitivity and Frequency Response Improvement of the Micro Thermal Convective Accelerometer With Structure Optimization

We present a theoretical model for transient analysis of the micro thermal convective accelerometer (MTCA). By leveraging this model, efficient parametric prediction can be calculated compared with time-consuming and complex CFD simulation and experimental testing. Based on the calculation results, it is recommended that a device with a thin film, a small size, and a small distance between detectors and microheater will achieve a faster frequency response, which is demonstrated by the experimental results using a serial of MTCAs fabricated with a CMOS compatible method. In addition, combined with the optimization of sensitivity, a guideline can be found that in order to improve the frequency response and sensitivity, the detector should be placed closer to the microheater when the sensor length of the device is larger. While, for the device with a smaller sensor length, detectors should be designed in the moderate region of the ratio of D/L. Except for frequency improvement, the relationship between the sensor size and sensitivity is also described and a device with an outstanding sensitivity of 7, $500~\mu \text{V}$ /g is created with a novel parallel stake method. Combining sensitivity and frequency variation with sensor size, a trade-off should be made when designing the MTCA. Above all, the recovery of this work is meaningful for the researchers to optimize their designs for the improvement of both sensitivity and frequency response.