MONOLITHIC 2-DIMENSIONAL ARRAYS OF MICROMACHINED MICROSTRUCTURES FOR INFRARED APPLICATIONS

Small micromachined structures (typically 10(-5) cm(2)) have been fabr icated that have very small thermal mass (c, about 10(-9) J/K) and tha t are suspended from the underlying silicon substrate by supports of s uch delicacy that the structures are extremely well thermally isolated from the substrate (thermal conductance to the substrate g of about 1 0(-7) W/K). This thermal conductance is close to the smallest value po ssible (about 10(-8) W/K) due to radiative energy exchange [1]. This h igh thermal isolation allows the microstructure temperature to be read ily controlled by very small heating currents, or very small amounts o f infrared (IR) incident IR flux. Large arrays of such microstructures have been fabricated on silicon wafers, complete with complex integra ted electronic circuits, and operated as 1) sensitive room-temperature IR sensors (''microbolometers'') for night-vision IR imaging and 2) l arge arrays of individually controllable IR microemitters, The latter provide dynamic infrared ''scene generators'' that allow realistic sim ulations of IR scenes, an important tool for the development of IR cam eras and IR missile seekers.