Gravimetric Chemical Sensor based on the Direct Integration of SWNTs on AlN Contour-Mode MEMS Resonators

This paper reports on the first demonstration of a gravimetric chemical sensor based on direct integration of Single Wall Carbon Nanotubes (SWNTs) grown by Chemical Vapor Deposition (CVD) on AlN Contour-Mode MicroElectroMechanical (MEMS) resonators. In this first prototype the ability of SWNTs to readily adsorb volatile organic chemicals has been combined with the capability of AlN Contour-Mode MEMS resonator to provide for different levels of sensitivity due to separate frequencies of operation on the same die. Two devices with resonance frequencies of 287 MHz and 442 MHz have been exposed to different concentrations of DMMP in the range from 80 to 800 ppm. Values of mass sensitivity equal to 1.8 KHz/pg and 2.65 KHz/pg respectively have been measured.