Dynamic range and sensitivity improvement in near-infrared detectors using silicon germanium bipolar complementary metal-oxide semiconductor technology

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Authors

Venter, Johan H.
Sinha, Saurabh

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Society of Photo-optical Instrumentation Engineers

Abstract

Classically gated infrared (IR) detectors have been implemented using charge-coupled devices (CCD). Bipolar complementary metal-oxide semiconductor (BiCMOS) technology emerged as a viable alternative platform for development. BiCMOS technology has a number of advantages over CCD and conventional CMOS technology, of which increased switching speed is one. The pixel topology used in this work is a reversed-biased diode connected heterojunction bipolar transistor. The disadvantage of CMOS detectors is the increased readout noise due to the increased on-chip switching compared to CCD, which degrades dynamic range (DR) and sensitivity. This yields increased switching speeds compared to conventional bipolar junction transistors. Sensitivity improved from 50 mA∕W (peak) at 430 nm in CCD detectors to 180 mA∕W (peak) (or 180; 000 V∕W) at 665 nm in BiCMOS detectors. Other CMOS IR detectors previously published in the literature showed sensitivity values from 2750 to 5000 V∕W or 100 mA∕W. The DR also improved from 47 and 53 dB to 70 dB. The sensitivity of conventional CCD detectors previously published is around 53 mA∕W. The second advantage is that detection in the near-IR band with conventional silicon integrated technology is possible. This work has shown increased detection capabilities up to 1.1 μm compared to Si detectors.

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Keywords

Heterojunctions, Detectors, Noise, Photodetectors, Charge-coupled devices (CCD), Infrared (IR)

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Citation

Venter, J & Sinha, S 2013, 'Dynamic range and sensitivity improvement in near-infrared detectors using silicon germanium bipolar complementary metal-oxide semiconductor technology', Optical Engineering, vol. 52, no. 4, pp. 044001-7.