Imaging and Spectroscopy - Monolithic InGaAs-on-silicon Detector with a CMOS Switched Capacitor Integrator (1994)

A.M. Joshi & F.J. Effenberger
Discovery Semiconductors, Inc.
119 Silvia Street
Ewing, NJ 08628


M. Grieco, G.H. Feng & W. Zhong
New Jersey Institute of Technology
Newark, NJ 07102


J. Ott
Stevens Institute of Technology
Hoboken, NJ 07030


We have successfully grown InGaAs detectors on the silicon substrate using the special technique of selective epitaxy. Small diameter (50 µm) selective area depositions of In0.5Ga0.5As on silicon have exhibited a lower dislocation density, and hence, better electrical performance. These InGaAs detectors are grown by molecular Beam Epitaxy (MBE). the final goal is to monolithically integrate InGaAs detectors with a silicon CMOS switched capacitor integrator. We have designed a CMOS switched-capacitor integrator (SCI) to realize a linear current-to-voltage conversion over a wide voltage range (-5 to +5V) with low noise characteristics. The SCI circuit consists of an operational amplifier with a feed back capacitor and a reset switch. The SCI circuit uses ±5V dual power supply and one -5 to +5V voltage pulse generator. the circuit was simulated using PSPICE and the chip layout was done with the Mentor Graphics.

Keywords: Selective epitaxy, InGaAs Detectors, CMOS Integrator, misfit Dislocations

*Published in SPIE Vol. 2290, pp. 430-437, 1994

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