Mid- and far-infrared hybrid focal plane arrays for astronomy

High performance 128x128 Si:As and Si:Sb Blocked-Impurity-Band (BIB) hybrid arrays have been developed for ground-based and airborne astronomy. These devices cover the 5-25 (Si:As) and 15-40 mu m (Si:Sb) portions of the spectrum. The peak defective quantum efficiencies exceed 50% for Si:As and 30% for Si:Sb. An anti-reflection coat is used to increase responsivity and to reduce internal reflections for the Si:As detectors. The multiplexer yields a linear output response vs, integrated charge. A special design feature of the multiplexer is a changeable nodal capacitance that allows dynamic switching of the well depth between 1.8x10(6) and 1.8x10(7) electrons. Thus, the array can be used in both narrow (spectrographic) and broadband (camera) instruments. The single-sample read noises for the two states are similar to 75 and similar to 760 electrons respectively. These devices have been used successfully to perform astronomical observations in a number of instruments.