Third generation focal plane array IR detection modules and applications (Invited Paper)

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 at AIM on quantum well (QWIP) and antimonide superlattices (SL) detection modules for ground and airborne applications in the high performance range. For spectral selective detection, a QWIP detector combining 3-5μm (MWIR) and 8-10μm (LWIR) detection in each pixel with coincident integration has been developed in a 384x288x2 format with 40 μm pitch. Excellent thermal resolution with NETD < 30mK @ F/2, 6.8 ms for both peak wavelengths (4.8 μm and 8.0 μm) has been achieved. Thanks to the well established QWIP technology, the pixel outage rates even in these complex structures are below 0.5% in both bands. QWIP dual band or dual color detectors provide good resolution as long as integration times in the order of 5-10ms can be tolerated. This is acceptable for all applications where no fast motions of the platform or the targets are to be expected. For rapidly changing scenes-like e.g. in case of missile warning applications for airborne platforms-a material system with higher quantum efficiency is required to limit integration times to typically 1ms. AIM and IAF selected antimonide based type II superlattices (SL) for such kind of applications. The SL technology provides-similar to QWIP's-an accurate engineering of sensitive layers by MBE with very good homogeneity and yield. While promising results on single SL pixels have been reported since many years, so far no SL based detection module could be realized. IAF and AIM last year managed to realize first most promising SL based detectors. Fully integrated IDCA's with a MWIR SL device with 256x256 pixels in 40´m pitch have been integrated and tested. The modules exhibit excellent thermal resolution of NETD<10mk @ F/2 and 5ms. Product improvement meanwhile allowed to reduce pixel outage rates below 1% i.e. down to a level as required for the military use of such detectors. Presently under development is therefore a dual color MWIR device based on SL technology and the existing 384x288 read out circuit (ROIC) used in the dual band QWIP device. This detector is primarily intended for the use in missile approach warning systems where the dual color capability significantly improves suppression of false alarms. Details of the modules and results of the electrooptical performance will be presented for the different items mentioned above.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.