Status Of SAT CID InSb Detector Technology And Applications

Abstract

This paper presents SAT indium antimonide Charge Injection Devices (C.I.D) Technology, post focal plane signal processing and some applications.These detectors are constituted by MOS capacitors realized on InSb wafers using integrated circuit -like processing. When a negative voltage is applied to the structure (put it into depletion) the capacitors form integrating detectors for use in 3 -5 pm band. Linear arrays constituted by a line of single capacitors, matrix arrays constituted by a group of two coupled MOS capacitors, collect and store photon generated charge carriers. In the last case, the selection of a site is accomplished by X -Y decoding technique.SAT manufactures currently line arrays with as many as 64 elements and staring arrays with as many as 32 x 32 elements. Works about 128 elements line arrays and 64 x 64 elements matrix array is being develloped.After a brief description of CID mechanisms this paper presents detectors manufacturing and focal plane evaluation method.Staring infrared imagers possess an inherent fixed pattern noise which is determined by the non uniformities in quantum and transfert efficiencies, dark current, electrical coupling circuitry. These defaults rust be compensated.On the other hand, staring arrays are characterized by a low integration time : so, a frame averager oust be used to be compatible with equipments frame rate and increase signal to noise ratio.This post signal processing used in an experimental camera is to be described. These works are defined in a contract with Direction des Recherches Etudes et Techniques (n° 83.34.073). Other civil and military applications are presented. INTRODIICTION Since 1975, SAT has been investigating various IR focal plane technologies including in particular Charge Injection Device (CID), as part of an extensive study program supported by the French "Direction Générale pour l'Armement" (French Department of Defense). As a result of this research, both line and area arrays of infrared detectors fa-red on InSb wafers have been developed for applications in the 3 -5 pm waveband.The particularly good performances demonstrated by these components has enabled them to be incorporated to a variety of equipment destined for both civil and military applications. CID MECHANISMCID detectors are MIS capacitors (Metal -Insulator -Semiconductor). In detector applications, these capacitors are biased into depletion to, form effective potential wells collecting and storing the charge carriers generated by the incident photons. These charge carriers are usually holes, since the arrays use N -type indium antimonide.When a negative voltage is suddenly applied to the gate of the MIS capacitor, the electrons are driven out of the region just under the gate, leaving behind fixed positive charge carriers in the crystal lattice of the substrate. These ions form an extensive positive charge region (depletion region) whose width is dependent on dopant density as well as on the voltage applied to the gate. A negative charge appears on the metal side of the s...