A Solidly Mounted Resonator With CMOS-Fabricated Acoustic Mirror For Low-Cost Air Quality Monitoring

This work presents a novel Solidly Mounted Resonator (SMR) device for use in a portable, low-cost and lowpower air quality monitor. The acoustic mirror, an essential part of the SMR device for energy confinement, is fabricated within a CMOS process, and advances upon current acoustic device technology. This CMOS-fabricated acoustic mirror will enable the device to be monolithically integrated and fabricated in high volume with reduced postprocessing steps compared to the state-of-the-art acoustic based sensors. The CMOS-fabricated acoustic mirror demonstrated good reflectivity with a high quality factor of 500. Experimental results on particulate matter sensing with the CMOS based SMR sensor showed a response of 117 kHz/ng when detecting fine particles (<;1 μm).