A Low-Power CMOS-MEMS Vibration Spectrum Analyzer

This work presents implementation and characterization of building blocks of a low-power miniaturized vibration spectrum analyzer. The proposed spectrum analyzer is comprised of an array of several piezoresistive cantilevers each covering a narrow frequency range (~15-100Hz) in the close vicinity of its resonance frequency. To cover the entire targeted frequency range (0-10kHz), two different device configurations, both utilizing piezoresistive strain gauges on microscale cantilevers, have been fabricated using a standard CMOS process with minimal mask-less post-CMOS micro-machining. Sensitivities as high as 9.73mV/g (at DC for 1mW of power consumed) and 14. SmV/g (at 7.2kHz for 1mW of power consumed) have been obtained for the lower and higher frequency configurations with a minimum resolution of 1.02mg and 0.2mg (for 1mW power consumption) respectively.