Competitive technologies for third generation infrared photon detectors

Abstract

Hitherto, two families of multielement infrared (IR) detectors are used for principal military and civilian infrared applications; one is used for scanning systems (first generation) and the other is used for staring systems (second generation). Third generation systems are being developed nowadays. In the common understanding, third generation IR systems provide enhanced capabilities like larger number of pixels, higher frame rates, better thermal resolution as well as multicolor functionality and other on-chip functions.In the paper, issues associated with the development and exploitation of materials used in fabrication of third generation infrared photon detectors are discussed. In this class of detectors two main competitors, HgCdTe photodiodes and quantum well photoconductors are considered. The performance figures of merit of state-of-the-art HgCdTe and QWIP focal plane arrays (FPAs) are similar because the main limitations come from the readout circuits. The metallurgical issues of the epitaxial layers such as uniformity and number of defected elements are the serious problems in the case of long wavelength infrared (LWIR) and very LWIR (VLWIR) HgCdTe FPAs. It is predicted that superlattice based InAs/GaInSb system grown on GaSb substrate seems to be an attractive to HgCdTe with good spatial uniformity and an ability to span cutoff wavelength from 3 to 25 µm. In this context the material properties of type II superlattices are considered more in detail.

Material and device characterization of Type-II InAs/GaSb superlattice infrared detectors

“…High performance photodetectors operating in the midwave (3 -5 µm) and longwave (8 -12 µm) infrared (IR) spectral domain are useful for a broad range of civil, industrial and spatial applications. Since the proposition made by Smith and Mailhiot [1], the Type-II InAs/GaSb superlattice (SL) material has been of great interest as it offers unique properties for infrared detection including a high absorption coefficient, low dark-currents and the possibility to address a wide range of wavelengths by tuning the SL band edges [2].…”

Monte Carlo simulation of photoelectric characteristics of 2D IR FPA detectors

“…При оптимизации фотоэлектрических и конструктивных параметров фоточувствительных элементов (ФЧЭ) многоэлементных фотоприемных устройств (ФПУ) основное внимание ранее уделялось проблеме уменьшения темновых токов диодов. Современная технология обеспечивает уровень темновых токов диодов, не ограничивающий чувствительность ИК ФПУ [1][2][3]; в связи с этим на передний план выходят вопросы, связанные с процессом сбора фотодиодами ФПУ фотогенерированных носителей заряда (НЗ), и с необходимостью учета распределения локальной квантовой эффективности по площади матрицы [4].…”

New material systems for third generation infrared photodetectors

“…Recently, type II InAs/GaInSb superlattices [20,21,[39][40][41] and QDIPs [42][43][44][45][46][47] have emerged as next two candidates for third generation infrared detectors. Table 2 compares the essential properties of type-II material system with well established competitors -HgCdTe photodiodes and QWIPs.…”

“…), array formats (up to 1280´720) and spectral-band sensitivity (MWIR/MWIR, MWIR/LWIR and LWIR/LWIR). Recently, type II InAs/ GaInSb superlattices have emerged as third candidate for third generation infrared detectors [20,21,35,[39][40][41].…”