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10 October 2001 Extended InGaAs on GaAs detectors for SWIR linear sensors
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High quality extended-wavelength InGaAs (80% In) has been grown heteroepitaxially on 3'-GaAs substrates by means of Molecular Beam Epitaxy (MBE). In contrast growth on InP, sensor manufacturing on GaAs substrates can be readily scaled to 6'. An additional benefit is the larger cut-off of the 80%- In material (2.5μm vs. 1.7μm). The photodiode layer design was optimized for maximum improvement of dark current with temperature. A high-uniformity and high- yield process was developed to manufacture bondable 128 pixel 50 μm pitch linear array sensors. To this end, a dedicated mesa-type process was developed assuring high uniformity in dark current and photoresponse. The sensors were designed for top-illumination. Sensors have been characterized electrically and optically at the intended thermo-electrical operation temperature (250K). The homogeneity of dark current and photoresponse was also evaluated at 250 K. The improvement in dark current as a function of temperature has been studied in more detail, yielding a zero bias resistance of approximately 2.5 MΩcm2 at 77K. A linear array has been bonded to a commercial CMOS read-out circuit and the functionality is shown. The sensor is suitable for spectroscopic and imaging applications in the short wavelength infrared (SWIR) region. Work is underway to develop sensors with smaller pitch and up to 512 pixels.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Joachim John, Lars Zimmermann, Stefan Nemeth, Thierry Colin, Patrick Merken, Staf Borghs, and Chris A. Van Hoof "Extended InGaAs on GaAs detectors for SWIR linear sensors", Proc. SPIE 4369, Infrared Technology and Applications XXVII, (10 October 2001);


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