ASELSAN has been developing new generation high operating temperature (HOT) infrared detectors to reduce the power consumption of T2SL detectors. In this paper, recent results for HOT T2SL detectors for mid-wavelength infrared (MWIR) technology at ASELSAN are presented. Performance is shown for 640x512 format 15 µm pitch IDDCA with average noise equivalent temperature (NETD) and pixel operability values of <25 mK (F/4) and >99.5% at 110 K, respectively. These NETD and operability values remain unaffected by temperature between 77 K and 110 K.
ASELSAN has made significant progress on developing its short-wave infrared (SWIR) technology, with a focus on improving dark current, quantum efficiency, and operability. In recent work, shunt current and generation-recombination current have been identified as the predominant dark current mechanisms. Shunt current can be suppressed by reducing the dangling bond count which requires optimizing the focal plane array passivation, and generation-recombination current can be reduced by improving the device design. Extensive work on process optimization employing various passivation schemes combined with theoretical layer design has lowered the SWIR focal plane array pixel dark current values down to < 1 nA/cm2. Furthermore, achieving low dark current without sacrificing high quantum efficiency (exceeding 80%), by building on the previous process and post-process work, has enhanced the sensor’s ability to capture faint signals. 640x512 format and 15 μm pitch SWIR focal plane arrays coupled with ASEL64015CG read-out circuits have consistently reached > 99.9% operability. After maturing the development work, ASELSAN launches its SWIR detector, LEOP-640/15-SW, pioneering the company’s photodetector production. In this paper, the results of the theoretical and experimental R and D work on LEOP photodetector development and production at ASELSAN are presented.
ASELSAN, the largest defense company in Türkiye, develops high performance electro-optical systems for various applications. Research and development activities have been carried out on developing HgCdTe (MCT) detectors for long-wavelength infrared (LWIR) and mid-wavelength infrared (MWIR). In this paper, recent results for VGA 15μm pitch MWIR MCT detectors at IDDCA level are presented. P-on-n MCT epilayers are used for FPA fabrication with either mesa or planar pixel structures. Typically, over 99% operability and less than 20mK NETD values are achieved for 15μm pitch 640x512 format MWIR MCT FPAs at IDDCA level (F/4) in a repeatable fashion. Thermal cycle, mechanical shock, vibration and environmental tests (such as storage and operation under hot and cold temperatures) were applied to these MWIR MCT IDDCAs and passed successfully. Besides ongoing efforts on development of FPAs with 15μm pixel pitch, development activities for pixel pitch reduction also initiated recently for MWIR MCT and very promising results are achieved.
Recent advances in short-wave infrared (SWIR) technology including numerous new applications in civil areas, fusion with visible wavelengths, and integration with active imaging systems triggered the SWIR photodetector research at ASELSAN for both passive and active imaging. SWIR focal plane arrays with a 640x512 format and 15μm pitch were developed and coupled with ASEL64015C readout circuits which had been designed at ASELSAN as well. Through extensive research and development dark current density values <10 nA/cm2 (at 20°C) and operabilities >;99% were achieved. This paper reviews the work that has been conducted on SWIR detector development at ASELSAN.
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