Chip-Scale MEMS-CMOS Multispectral Infrared Chemical Sensor

Abstract

This paper reports on an ultra-miniaturized multispectral infrared (IR) chemical sensor based on an array of plasmonically-enhanced MEMS resonant IR detectors and a single multiplexed CMOS IC readout. The unique combination of such a piezoelectric-plasmonic MEMS sensing technology with a low-power CMOS read-out circuitry results in a frequency-domain IR spectrometer microsystem characterized by an ultra-miniaturized footprint (total chip area of ≈ 1.53mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ), low power consumption ( ≈ 1.07mW), and fast response ( per spectral scan). Thanks to the excellent IR detection capability (noise equivalent power, NEP ≈ 402 pW/Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> and thermal time constant, τ ~ 7.3 ms) and the plasmonic-enabled high spectral resolution (λ0=3 ~ 6 μm, full-width-at-half-maximum, ), the CMOS-MEMS spectrometer prototype can discriminate between acetone and hexane via transmission spectroscopy. These results prove a great potential for the development of fast, accurate, and ultra-miniaturized IR spectrometer microsystems suitable for mobile IR characteristic measurements.