Studies on the enhancement of sensitivity in SOI-MEMS Piezoelectric Accelerometer for low frequency applications

Abstract

In the present paper the design, fabrication and characterization of the SOI-MEMS piezoelectric accelerometer is reported. MEMS Accelerometers developed by many researchers in the literature have achieved the necessary high sensitivity at high frequencies. The main challenge of this work is to design an accelerometer with high sensitivity at low frequencies. The analytical modeling and FEM analysis were performed on the device to arrive at the optimized design of the device. The optimized accelerometer was fabricated that involves different fabrication steps like thermal oxidation, sputtering and sol-gel deposition techniques. The same was tested using a shaker set up.  The measured charge sensitivity was 2.472 pC/g and the voltage sensitivity was found to be 18 mV/g at a resonant frequency of 140 Hz. When Z-directional acceleration is applied to the fabricated accelerometer at room temperature, the sensitivity for this acceleration is about 18 mV/g the cross-axis sensitivities are about 0.01 mV/g. In the case of X- and Y-directional accelerations at room temperature, the voltage sensitivities are about 11mV/g and 14mV/g respectively, and the cross-axis sensitivities are about 0.01 mV/g.