Dual color IR detection modules, trends and applications

Abstract

The 3rd generation of infrared (IR) detection modules is expected to provide advanced features like higher resolution 1024x1024 or 1280x720 pixels and/or new functions like multicolor or multi band capability, higher frame rates and better thermal resolution. This paper is intended to present the current status and trends at AIM on antimonide type II superlattices (SL) dual color detection module developments for ground and airborne applications in the high performance range, where rapidly changing scenes - like e.g. in case of missile warning applications for airborne platforms or ground based sniper detection systems - require temporal signal coincidence with integration times of typically 1ms. AIM and IAF selected antimonide based type II superlattices (SL) for such kind of applications. The type II SL technology provides - similar to QWIP's - an accurate engineering of sensitive layers by MBE with very good homogeneity and yield. IAF and AIM managed already to realize a dual color 384x288 IR module based on this technology. It combines spectral selective detection in the 3 - 4&mgr;m wavelength range and 4 - 5 &mgr;m wavelength range in each pixel with coincident integration in a 384x288x2 format and 40x40 &mgr;m2 pitch. Excellent thermal resolution with NETD < 12 mK @ F/2, 2.8 ms for the longer wavelength range (red band) and NETD < 22 mK @ F/2, 2.8 ms for the shorter wavelength range (blue band) were reported. In the meantime a square design of 256x256x2 pixel with a reduced pitch of 30x30 &mgr;m2 is in preparation. In this case with 2 Indium bumps per pixel and a third common contact for all pixels required for temporal coincidence is connected at the outer area of the array. The fill factor is approx. 65% for both wavelength ranges. The reduced size of the array enables the use of a smaller dewar with reduced cooling power and significantly reduced weight and broadens the scope of applications where weight and costs is essential. Design aspects and expected performances are discussed

Third-generation infrared photodetector arrays

“…A square design of 256ϫ 256 FPA with a reduced pitch of 30ϫ 30 m 2 is currently in development. 184 The reduction in pixel size can be achieved by using only two indium bumps per pixel. These very promising results confirm that the antimonide SL technology is now a direct competitor to MBE HgCdTe dualcolor technology.…”

Standard format two-color CMOS ROIC for SLS detectors

“…With the extra information provided by two possibly different wavelength bands on the same FPA, the characteristics of objects become more distinct. This extra distinction allows for the fast detection of objects with minimal error and minimal computing power [7]. The extra image information available by comparing and contrasting the two colors can provide valuable data in military, medical, geological and astronomy applications, as well as the ability to easily identify everyday objects for commercial applications [8].…”

High performance two-color one megapixel CMOS ROIC for QWIP detectors

“…With the extra information provided by two wavelength bands, the characteristics of objects become more distinct. This extra distinction allows for the fast detection of objects with minimal error and minimal computing power [3]. The extra image information available by comparing and contrasting the two colors can provide valuable data in military, medical, geological and astronomy applications as well as the ability to easily identify everyday objects for commercial applications.…”