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8 September 1995 Pb1-xSnxSe-on-Si LWIR thermal imaging system
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A demonstrational thermal imaging LWIR camera system is described which is based on photovoltaic Pb1-xSnxSe-on-Si infrared sensor arrays. Epitaxial Pb1-xSnxSe layers, about 2 micrometer thick, are grown by molecular beam epitaxy onto 3 inch Si(111) substrates, and employing an intermediate CaF2 buffer layer of only 2 nm thickness for compatibility reasons. Linear arrays with 256 pixels on 50 micrometer centers are fabricated in the layers with a batch photolithographic technique. Cut- off wavelength is about 10 - 10.5 micrometer at operating temperatures of 80 - 120 K, and quantum efficiencies greater than 60%. The sensors operate near BLIP. The read-out electronics chips contain, for each sensor, an integrator with a low noise JFET input transistor, correlated multiple sampling, and a sample and hold amplifier. They are wire- bonded to the sensor array. The JFET input transistors allow it to amplify from much lower source impedances (down to less than 10 kOhm) than with CMOS design without adding significant noise. Infrared sensors with lower impedances, operation at higher temperature, or sensors with longer cut-off wavelengths can therefore be used.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Hans Zogg, Alexander Fach, Joachim John, Jiri Masek, Peter Mueller, Carmine Paglino, and Werner Buttler "Pb1-xSnxSe-on-Si LWIR thermal imaging system", Proc. SPIE 2552, Infrared Technology XXI, (8 September 1995);

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