Ss-DNA functionalized array of ALN Contour-Mode NEMS Resonant Sensors with single CMOS multiplexed oscillator for sub-ppb detection of volatile organic chemicals

This paper reports on the design and experimental verification of the first prototype of a resonant sensing platform based on nanoscaled aluminum nitride Contour-Mode Resonant Sensors (CMR-S) for selective detection of sub-ppb levels of volatile organic chemicals (VOCs). For the first time arrays of 8 nano-CMR-S were fabricated on the same chip and functionalized with two different thiol-terminated ss-DNA sequences. A low noise and low power (as low as 224 μW) CMOS circuit read-out capable of monitoring the responses of each NEMS sensor in a time-multiplexed mode was used. A ss-DNA sequence dependant adsorption of two vapors, such as DNT and DMMP, was recorded. Concentrations of DMMP and DNT as low as 700 part per billion (ppb) and 700 part per trillion (ppt), respectively, were experimentally detected. A limit of detection to mass per unit area as low as ~60 zg/μm² was extracted by noise characterization of the sensor array.