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Optoelectronics & Microsystems Lab. Politecnico di Milano, Dip. Elettronica e Informazione, Milano, Italy. STAFF. COVA, S. Full Professor GHIONI, M. Full Professor ZAPPA, F. Associate Professor GIUDICE, A. Post-Doc Research Associate RECH, I. Post-Doc Research Associate
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Optoelectronics & Microsystems Lab Politecnico di Milano, Dip. Elettronica e Informazione, Milano, Italy
STAFF • COVA, S. Full Professor • GHIONI, M. Full Professor • ZAPPA, F. Associate Professor • GIUDICE, A. Post-Doc Research Associate • RECH, I. Post-Doc Research Associate • LABANCA, I. Research Associate • GALLIVANONI, A. Research Associate • TISA, S. Ph.D. Student • RESTELLI, A. Ph.D. Student • TOSI, A. Ph.D. Student • GULINATTI, A. Ph.D. Student
Core Know-How • Microelectronic Detectors and Circuits • Measurement Techniques and Instrumentation for detecting and measuring optical signals with ultra-high sensitivity and picosecond resolution
APD SPAD Single-Photon Avalanche Diode Avalanche PhotoDiode • Bias: well ABOVE breakdown • Geiger-mode: it’s a TRIGGER device!! • Gain: meaningless ... or “infinite”!! • Bias: slightly BELOWbreakdown • Linear-mode: it’s an AMPLIFIER • Gain: limited < 1000
Thick Si SPAD Thin Si SPAD Planar structure typical active region: 20 m diameter 1m thick Reach-Trough structure typical active region: 200 m diameter 30m thick
Thick Si SPAD’s Thin Si SPAD’s • Very good QE and low noise • Sub-nanosecond timing • High voltage : 300 to 400V • High dissipation : Peltier cooler required • Ultra-pure high-resistivity Si substrate • Dedicated fabrication process • NOT COMPATIBLE with array detector and IC’s • Delicate and degradable • Very expensive • SINGLE COMMERCIAL SOURCE • Good QE and low noise • Picosecond timing • Low voltage : 15 to 40V • Low power : cooling not necessary • Standard Si substrate • Planar fabrication process • COMPATIBLE with array detector and IC’s (integrated circuits) • Robust and rugged • Low-cost • NO COMMERCIAL SOURCE TODAY
Passive quenching is simple... Current Pulses Diode Voltage • … but suffers from • long, not well defined deadtime • low max counting rate < 100kc/s • photon timing spread • et al
Activequenching…. • ...provides: • short, well-defined deadtime • high counting rate > 1 Mc/s • good photon timing • standard logic output Output Pulses P.Antognetti, S.Cova, A.Longoni IEEE Ispra Nucl.El.Symp. (1975) Euratom Publ. EUR 537e
AQC evolution Earlier modules in the 80’s Compact modules in the 90’s Integrated AQC today
iAQC - Integrated Active Quenching Circuit Input sensing and quenching stage • F.Zappa, S.Cova, M.Ghioni, “Monolithic circuit of active quenching and active reset for avalanche photodiodes ”, US Patent 6,541,752 B2, date April 1,2003 (priority date March 9, 2000); European patent application n. 01200852.2-2217, fil. March 6, 2001. • F. Zappa, A. Lotito, A. C. Giudice, S. Cova, and M. Ghioni, IEEE J. Solid-State Circuits, 38, 1298-1301 (2003).
+VHIGH +5V IN OUT WIDTH GATE GND iAQC - Integrated Active Quenching Circuit CMOS design
iAQC - Integrated Active Quenching Circuit • Practical advantages • Miniaturization mini-module detectors • Low-Power Consumption portable modules • Ruggedness and Reliability • Plus improved performance • Reduced Capacitance • Improved Photon Timing • Reduced Avalanche charge • Reduced Afterpulsing • Reduced Photoemission reduced crosstalk in arrays
Photon Timing comparison PerkinElmer SPCM (SLIKTM diode) Planar thin Si-SPAD