Germanium imaging sensor

Abstract

The development and evaluation of a germanium imaging sensor is described. The sensor, comprised of an electronbeam-scanned photodiode array,was designed for air-glow operation. Surface-barrier photodiode arrays were developed for optimized imaging, and their processing provided a powerful technique for preserving the characteristic properties of high-resistivity germanium by limiting the maximum processing temperature to 54o"C. Photodiode-array processing was developed to a high degree of sophistication, but for satisfactory imaging using airglow illumination, additional development is required to improve the electronbeam characteristics of the tube, array cooling, and video amplifier. The best sensor had a quantum efficiency of~67.4 percent at 1.55 pm and 90"K for an absolute sensitivity of 0.84 A/W.