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1 January 2008 Miniaturized InSb photovoltaic infrared sensor operating at room temperature
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This paper reports the development of a novel InSb infrared photovoltaic sensor (PVS) operating at room temperature. The PVS consists of an InSb p+p-n+ structure grown on semi-insulating GaAs(100) substrate, with a p+-Al0.17In0.83Sb barrier layer between the p+ and p- layers to reduce diffusion of photoexcited electrons. Photodiodes were fabricated by wet etching, and, using a 500-K blackbody, we obtained detectivity D*=2.8×108 cm Hz1/2/W and responsivity RV=1.9 kV/W at room temperature. The SNR was improved with the serial connection of 700 photodiodes patterned on a 600×600-μm2 chip. On increasing the number N of connected photodiodes, the SNR was improved by a factor of N1/2. The responsivity was constant for signals ranging from dc to 500 Hz. From spectral response measurements a cutoff wavelength of 6.8 μm was obtained. The PVS was flip-chip bonded on pre-amplifier IC, allowing the shortest possible connection between the PVS and the pre-amplifier, making the system immune to electromagnetic noise. The system was finally encapsulated in a dual flat nonleaded package with a window, which exposes the back of the GaAs substrate, allowing the infrared light incidence. The device is small (2.2×2.7×0.7 mm3), operates at room temperature, and is able to detect human body radiation in the middle IR range.
©(2008) Society of Photo-Optical Instrumentation Engineers (SPIE)
Edson G. Camargo, Koichiro Ueno, Yoshifumi Kawakami, Yoshitaka Moriyasu, Kazuhiro Nagase, M. Sato, Hidetoshi Endo, Kazutoshi Ishibashi, and Naohiro Kuze "Miniaturized InSb photovoltaic infrared sensor operating at room temperature," Optical Engineering 47(1), 014402 (1 January 2008).
Published: 1 January 2008


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