An 8 mW Fully Integrated Regenerative Resonant MEMS CO2 Sensor Using Linear Polyethylenimine as a Capture Layer

A fully integrated regenerative CO2 MEMS sensor using a micro-resonator coated with Linear Polyethylenimine as an adsorbent layer is presented. The pyramidal cantilever micro-resonator used has a resonant frequency of 315.24 kHz with a Q factor of 1125 at atmospheric pressure. The micro-resonator was integrated with a sustaining amplifier that consumes 8 mW. The MEMS sensor sensitivity was characterized in a CO2 concentration range from 1200 to 10500 ppm, showing a frequency shift of -12 Hz at 1200 ppm with a slope of -3.50 mHz / ppm over the characterized range. The adsorption and recovery times are characterized to be as low as 170 seconds and 280 seconds, respectively. The impacts of pressure, temperature and humidity on the sensor were also characterized. The behavior of the MEMS sensor is compared to that of an optical CO2 sensor.

Automated summary

This paper presents a fully integrated regenerative CO2 MEMS sensor using a micro-resonator coated with Linear Polyethylenimine as an adsorbent layer, showing high sensitivity and short adsorption and recovery times. The impacts of pressure, temperature and humidity on the sensor were thoroughly characterized. Comparison with an optical CO2 sensor was also conducted.