This paper presents a bi-material microcantilever focal plane array (FPA) for uncooled infrared (IR) imaging. The FPA was fabricated by a bulk silicon micromachining method with substrate silicon selectively removed by deep reactive ion etching (DRIE) technique at the area where each cantilever pixel is located. The absorbance of the IR radiation can be improved by 48% due to the selective removal of the substrate, and hence the noise equivalent temperature difference (NETD) of the FPA can be reduced by 32% compared to the one fabricated by sacrificial layer technique, approaching 60mK. The thermomechanical sensitivity and the response time of the FPA were measured and calculated to be 112nm/K and 15ms, respectively. An image of human bodies was captured by an optical readout method.
Optical-readout micro-cantilever array IR imaging system and performance analysis
