256 x 256 pixel InSb FPA for SIRTF and other astronomical applications

As part of the NASA Space Infrared Telescope Facility (SIRTF), a low noise multiplexer has been developed. The hybridization of this multiplexer to a high quality indium antimonide (InSb) photodiode array has resulted in a MWIR detector of outstanding performance. The multiplexer is made of a 256 X 256 array of source follower amplifiers on a 30 micron square pitch. Random access binary decoders are used to access each pixel of the array, allowing any read-out scheme to be implemented. Dark current has been measured at temperatures ranging from 4 K to 77 K. Generation recombination currents dominate above 45 K. With 100 mV of reverse bias applied, less than 3 X 10-17 A is typical below 50 K with 8 X 10-19 A (5 electrons/second) at 4 K. Under the same conditions 0.25 pA was measured at 77 K. Read noise has been measured as low as 186 electrons using non-correlated techniques. Detector quantum efficiency is 50 to 80 percent through the entire wavelength band of 1 to 5 micrometers .