Active solid-state devices (e.g. – transistors – solid-state diode – Thin active physical layer which is – Heterojunction
Reexamination Certificate
1998-11-03
2002-03-12
Abraham, Fetsum (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Thin active physical layer which is
Heterojunction
C257S053000, C257S082000, C257S098000, C257S090000, C257S184000, C257S226000, C257S228000, C257S234000, C250S338100, C250S338200, C250S339010, C250S339020
Reexamination Certificate
active
06355939
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention pertains in general to infrared detectors and in particular to such detectors which are responsive to multiple bands of infrared radiation.
BACKGROUND OF THE INVENTION
Infrared detectors are used for collecting image information under conditions which do not allow generally conventional optical observation, such as at night or through clouds, haze or dust. The information gathered within infrared imaging can be enhanced if multiple bands of infrared radiation can be collected concurrently. This is much like color in an optical image. Infrared radiation in different bands can be indicative of different elements in a scene, such as different materials, reflectivity, temperatures and so forth. Therefore, for optimum viewing through use of infrared radiation, it is desired to have a sensor capable of concurrently detecting multiple bands of infrared radiation.
Multi-band infrared sensing has been performed with detectors of different types. Semiconductor infrared detectors are becoming among the most widely used, and for observing scenes, a well known type is referred to as a “staring array.” One configuration for a multi-band staring array detects each of the different bands of radiation with a planar layer of photosensitive material with the multiple layers in a stack wherein all of the upper layers are transparent to the radiation absorbed by the lower layers.
The present invention is directed to a configuration for an infrared detector which has a unique configuration that is particularly adaptable for use with multi-quantum well (MQW) photosensitive detection material.
SUMMARY OF THE INVENTION
A selected embodiment of the present invention is a multi-band quantum well infrared photodetector which has a pixel structure that includes a plurality of co-planar sections, with each section being responsive to a respective, different band of infrared radiation. Each section of the pixel structure has a plurality of elongate, multiple quantum well infrared radiation absorbing elements. Each of the elements has first and second opposite longitudinal surfaces. The elements in each section have a physical configuration which includes a periodic spacing dimension for the elements and a width dimension for the elements. Each of the sections has a respective, different configuration. The multiple quantum well elements comprise a diffraction grating for the infrared radiation. A first contact includes a plurality of planar, electrically interconnected strips respectively in contact with and extending along the first surfaces of the multiple quantum well elements. A plurality of second contacts are respectively located in each of the sections with the second contact in each section electrically connected to the second surfaces of the multiple quantum well elements in the corresponding one of the sections. The first and second contacts are positioned on opposite longitudinal sides of each of said multiple quantum well elements to provide current flow through said elements in a direction substantially transverse to the axis of the elements. A planar reflector is provided for the infrared radiation. The reflector is positioned on an opposite side of the second contacts from the multiple quantum well elements.
REFERENCES:
patent: 3962578 (1976-06-01), Roschen
patent: 4158133 (1979-06-01), Spaeth et al.
patent: 4596930 (1986-06-01), Steil et al.
patent: 4625389 (1986-12-01), Readhead
patent: 4822998 (1989-04-01), Yokota et al.
patent: 4956555 (1990-09-01), Woodberry
patent: 5013918 (1991-05-01), Choi
patent: 5023944 (1991-06-01), Bradley
patent: 5157258 (1992-10-01), Gunning, III et al.
patent: 5198659 (1993-03-01), Smith et al.
patent: 5329136 (1994-07-01), Goossen
patent: 5384469 (1995-01-01), Choi
patent: 5444236 (1995-08-01), Ludington et al.
patent: 5485015 (1996-01-01), Choi
patent: 5539206 (1996-07-01), Schimert
patent: 5543628 (1996-08-01), Chow et al.
patent: 5552603 (1996-09-01), Stokes
patent: 5646421 (1997-07-01), Liu
“Multicolor Voltage-Tunable Quantum-Well Infrared Photodetector”.
H.C. Liu, Jianmeng Li, J.R. Thompson, Z.R. Wasilewski, M. Buchanan, and J.G. Simmons,IEEE Electron Device Letters, vol. 14, No. 12, EDLEDZ, (ISSN 0741-3106), Dec. 1993, pp. 566-568; published by IEEE Electron Devices Society.
“Multicolor Quantum Well Infrared Photodetectors”.
M.Z. Tidrow, Army Research Lab., Adelphi, MD 20783, 1998.
“NeuroSeek Dual-Color Image Processing Infrared Focal Plane Array”.
Paul L. McCarley, Mark A. Massie, Christopher R. Baxter, Buu L. Huynh, Proceedings of the SPIE—The International Society for Optical Engineering—Infrared Readout Electronics IV, vol. 3360, Apr. 13, 1998, pp. 13-27, part of the SPIE Conference on Infrared Readout Electronics IV, Apr. 1998, Orlando, FL.
“Two-color imaging by the use of patterned optical filters bonded to focal-plane-array detectors”.
N.S. Gluck, R.B. Bailey, R. de la Rosa, and R.L. Hall,Applied Optics,vol. 35, No. 28, Oct. 1, 1996, pp. 5520-5523.
“Recent Progress on Multicolor Quantum Well Infrared Photodetectors”.
Meimel Z. Tidrow, Army Research Laboratory, Fort Monmouth, NJ 07703-5601, Proceedings of the Eighth International Conference on Narrow Gap Semiconductors, Shanghai, China, Apr. 21-24, 1997, p. 155, pub. World Scientific, Singapore, pub. date 1998.
Abraham Fetsum
Lockheed Martin Corporation
Sadacca Stephen S.
Sidley Austin Brown & Wood
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