Investigation of Microcantilever Sensor for Explosive Detection

In this study we investigate the use of microcantilever sensors for explosives detection. An array of microcantilevers consisting of gold (Au) and silicon nitride (Si₃N₄) thin-films of sub-micron thickness acts as a thermal bimorph. A microheater is fabricated in-situ at the base of each microcantilever in the array. When the microheaters are addressed individually using different actuation currents, each microcantilever undergoes thermo-mechanical deformation by different amounts which are then tracked individually by monitoring each reflected ray from a laser illuminating the array of microcantilevers. The threshold current values for the differential actuation of the microcantilevers are correlated with the auto-ignition temperature of a particular explosive (or combustible vapor) and its corresponding vapor pressure. In this study numerical simulations are also performed to study the variation of temperature, species concentration and deflection of individual microcantilevers as a function of actuation current.