REMOTE INFRARED RADIATION DETECTION USING PIEZORESISTIVE MICROCANTILEVERS

A novel micromechanical infrared (IR) radiation sensor has been develo ped using commercially available piezoresistive microcantilevers. Micr ocantilevers coated with a heat absorbing layer undergo bending due to the differential stress between the top layer (coating and the substr ate, The bending causes a change in the piezoresistance and is proport ional to the amount of heat absorbed. The microcantilever IR sensor ex hibits two distinct thermal responses: a fast one (<ms) and a slower o ne (similar to 10 ms). A noise equivalent power (at a modulation frequ ency of 30 I-It) was estimated to be similar to 70 nW/Hz(1/2). This va lue can be further reduced by designing microcantilevers with better t hermal isolation that can allow microcantilevers to be used as uncoole d IR radiation detectors. (C) 1996 American Institute of Physics.