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19 March 1999 Monolithic SiGe/Si quantum well sensor circuit for the 8- to 12- μm band
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Long wavelength Si0.8Ge0.2/Si quantum well infrared photodetectors (QWIPs) grown by low pressure CVD have been fabricated both as discrete devices and integrated onto a CMOS readout circuit to produce a monolithic Si-based sensor circuit for detection of thermal radiation. The peak photoresponse of the detectors near 8 micrometer is dominated by transitions to unbound final states associated with the spin-orbit split-off valence band. These optical transitions are allowed by symmetry reduction in the quantum wells, which is also evident in the electrical properties. The electrical noise is nearly ideal for temperatures up to 70 K, with no excess low frequency flicker noise. The capture probability for photoexcited holes into the quantum wells is approximately 0.55 at low temperature. The external 500 K black body responsivities for both the discrete and the monolithically integrated QWIPs are approximately 1.8 mA W-1 at 1 V bias, corresponding to a single pass of the radiation through the detectors. There is no degradation of either the CMOS transistors or the QWIPS caused by the integration process to create the monolithic sensor circuit.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
David J. Robbins, John L. Glasper, Carl J. Anthony, Michael J. Uren, Roger Timothy Carline, David C. Herbert, and Weng Y. Leong "Monolithic SiGe/Si quantum well sensor circuit for the 8- to 12- μm band", Proc. SPIE 3630, Silicon-based Optoelectronics, (19 March 1999);

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