Megapixel InGaAs arrays for low background applications--美国传感器公司05年

Megapixel InGaAs Arrays for Low Background Applications* Alan Hoffman**, Todd Sessler, Joseph Rosbeck, David Acton; Raytheon Vision Systems, Goleta, California, Martin Ettenberg; Sensors Unlimited, Inc., Princeton, New Jersey ABSTRACT Large focal planes with InGaAs detector arrays have been developed that meet the demanding requirements of astronomy and other low background systems. With high quantum efficiency between 0.9 and 1.7 µm, the InGaAs detectors are ideally suited for many SWIR applications. This paper describes two types of arrays with more than one million detector elements—one with 1280 × 1024 elements and the other with 1024 × 1024 elements—developed by Raytheon Vision Systems with detectors provided by Sensors Unlimited. The detector elements of both formats are on a 20 µm pitch. The 1024 × 1024 array utilizes a standard Virgo astronomy multiplexer (readout) that reads out the array at a maximum frame rate of 8 Hz. An innovative readout was designed for the 1280 × 1024 array with the support of DARPA's MANTIS program. This readout features a high gain front-end amplifier that can operate up to a 60 Hz frame rate and is designed to operate at room temperature. Summary performance data of each of these array types are presented. Keywords: infrared, SWIR, InGaAs, Virgo, MANTIS 1. INTRODUCTION Several applications require high-sensitivity focal planes in the 0.9 to 1.7 µm band. Among these are astronomy and passive night vision. Astronomers require extremely large, low noise focal planes to meet many of their science goals. Passive night vision systems that operate near room temperature, have the spatial resolution of high-definition TV, and can detect intruders on the darkest nights are desired for military applications. Detectors sensitive in the short wavelength end of the SWIR band, such as InGaAs, can operate at higher temperatures than traditional infrared detectors while, at the same time, maintain high sensitivity. InGaAs arrays, with the proper high-performance readout integrated circuits (ROICs), can meet the goals of both of these low-background applications. This paper describes two large-format InGaAs Sensor Chip Assemblies (SCAs) that were developed as part of DARPA's MANTIS (Multispectral Adaptive Networked Tactical Imaging System) program. One is a 1024 × 1024 array with the detector hybridized to an astronomy-class ROIC. The other is a 1280 × 1024 array hybridized to an innovative ROIC developed specifically for MANTIS. Both of these SCA designs have 20 µm pitch between detector elements (pixels). 2. DETECTOR SPECTRAL CHARACTERISTICS A number of high performance detector materials are available for low-background light detection. Both HgCdTe and InGaAs are materials whose bandgap – and therefore their cutoff wavelength – can be adjusted by changing the atomic ratios and can be tuned to detect at 1.7 µm. In addition, In0.53Ga0.47As is lattice-matched to InP, the common substrate for these detectors, when the cutoff wavelength is 1.7 µm. The spectral quantum efficiency of InGaAs is shown in Figure 1. Also shown in this figure is the response of 3rd generation night vision goggles and the emission of the night sky on a moonless night. This graphically illustrates the amount of light available for a reflective signal in the bands of interest. There is approximately an order of magnitude more natural light in the 0.9 to 1.7 µm band than in the 3rd generation band. Recent measurements at NVESD show an even greater contrast between visible and SWIR light.1 * ** Support provided by DARPA contract NBCH030074 ahoffman@http://doc.xuehai.net; phone: 805-562-2230; fax: 805-562-2127 Approved for Public Release, Distribution Unlimited 32 Infrared Technology and Applications XXXI, edited by Bjørn F. Andresen, Gabor F. Fulop, Proc. of SPIE Vol. 5783 (SPIE, Bellingham, WA, 2005) 0277-786X/05/$15 · doi: 10.1117/12.607635 Downloaded From: http://doc.xuehai.net/ on 11/20/2013 Terms of Use: http://doc.xuehai.net/terms

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