Sensitivity Improvement of Micro Thermal Convective Accelerometer with Structure Optimization: Theoretical and Experimental Studies

Abstract

For the first time, we conduct the structure optimization of the micro thermal convective accelerometer (MTCA). Firstly, the effects of sensor size (L), the location of detectors (D) and the cover height (H) on the performance are deeply analyzed by means of the proposed theoretical model. Six types of micro thermal convective accelerometers with parallel-stack detectors are fabricated by means of the CMOS compatible fabrication process to enhance the sensitivity. Both the theoretical and experimental results demonstrated that larger sensor size and cover height could improve the sensitivity of MTCA. Additionally, increasing sensor size would lead to a shift of the normalized optimal distance to the heater side. By means of the structure optimization and the parallel-stack method with three pairs of detectors, a MTCA with the sensor length of 1600μm is achieved with an outstanding sensitivity of 7075μV/g (gain=1) and normalized sensitivity/power (S/P) ratio of 201.4 μV/g/mW, which is twenty-fold larger than the state of art.