Megapixel digital InSb detector for midwave infrared imaging

Abstract

Since the late 1990s Semiconductor devices (SCDs) has developed and manufactured a variety of InSb two-dimensional (2D) focal plane arrays (FPAs) that were implemented in many infrared (IR) systems and applications. SCD routinely manufactures both analog and digital InSb FPAs with array formats of 320×256, 480×384, and 640×512 elements, and pitch size in the range 15 to 30 μm. These FPAs are available in many packaging configurations, including fully integrated detector-Dewarcooler-assembly, with either closed-cycle Stirling or open-loop JouleThomson coolers. In response to a need for very high resolution midwave IR (MWIR) detectors and systems, SCD has developed a large format 2D InSb detector with 1280×1024 elements and pixel size of 15 μm. A digital readout integrated circuit (ROIC) is coupled by flip-chip bonding to the megapixel InSb array. The ROIC is fabricated in CMOS 0.18-μm technology, that enables the small pixel circuitry and relatively low power generation at the focal plane. The digital ROIC has an analog to digital (A/D) converter per-channel and allows for full frame readout at a rate of 100 Hz. Such on-chip A/D conversion eliminates the need for several A/D converters with fairly high power consumption at the system level. The digital readout, together with the InSb detector technology, lead to a wide linear dynamic range and low residual nonuniformity, which is stable over a long period of time following a nonuniformity correction procedure. A special Dewar was designed to withstand harsh environmental conditions while minimizing the contribution to the heat load of the detector. The Dewar together with the low power ROIC, enable a megapixel detector with overall low size, weight, and power with respect to comparable large format detectors. A variety of applications with this detector make use of different cold shields with different f-number and spectral filters. In this paper we present actual performance characteristics of the megapixel InSb detector and demonstrate its high manufacturability. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

Cryogenic measurements of a digital pixel readout integrated circuit for LWIR

“…Although column parallel architectures are very common [4,5] ,pixel parallel conversion (digital pixels) offers a significantly higher dynamic range due to the exponential relationship between their charge handling capacity and pixel area, since the charge storage is in the digital domain. In DROICs with column parallel ADCs, signal chain resembles to an analog equivalent ROIC i.e charge is stored on an integration capacitor and charge handling capacity scales linearly with pixel area.…”

Electronic structure of InSb (001), (110), and (111)B surfaces

“…InSb is a III-V zincblende semiconductor with a small (∼0.2 eV) band gap and a high (∼80, 000 cm 2 V -1 s -1 ) room temperature electron mobility 7 . The small band gap of InSb has enabled the use of InSb for infrared detection 8,9 . InSb has been explored as a material for high-speed and low power a) Present Address: Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305 b) cjpalm@ucsb.edu transistors due to its high electron mobility [10][11][12] .…”

Research progress on digital ROIC of infrared focal plane array detector

“…The present development trend of infrared focal plane array technology is especially in the following areas to produce high performance infrared detectors due to the rising relevance of infrared focal plane in military technology [18][19][20][21][22][23]：…”