Photon Counting Microdetectors and Applications: Retrospect and Prospect

Sergio Cova IEEE-LEOS Distinguished Lecturer Politecnico di Milano DEI, Milano, Italy Photon Counting Microdetectors and Applications: Retrospect and Prospect Micro Photon Devices, Via Stradivari 4, 39100 Bolzano, Italy, www.micro-photon-devices.com

Biography - Dr. Sergio Cova Full professor of Electronics since 1976 @ Politecnico di Milano (POLIMI), Italy Author of over a hundred and seventy papers in international refereed journals and conferences and of five international patents (USA and Europe) Pioneered the development of Single-Photon Avalanche Diodes (SPAD), inventing the active-quenching circuit (AQC). His research group developed AQCs in successive generations and was the first (and so far is the only one) to develop monolithic integrated AQCs. Contributed to diversified applications of photon-counting detectors: fluorescence measurements for DNA and protein analysis and single-molecule studies; characterization of optical fibers and laser; adaptive optics systems in telescopes; non-invasive testing of ULSI circuits; and others. In 2005 established with other colleagues of Politecnico di Milano the university spin-off company MPD Micro-Photon-Devices, intended for producing industrially and making widely available to experimenters the photon counting microdetectors developed in the research at POLIMI.

Outline Introduction: Single Photon (SP) Detection Micro-Detectors: Single Photon Avalanche Diodes (SPAD) and associated electronics Application Cases Conclusions and Outlook

Introduction: Single Photon (SP) Detection Why SP Detection How to Detect SP Why Solid-State SP Micro-Detectors

Electronic Noise impairs Detector Sensitivity DETECTOR LOAD ELECTRONICS Detector Signal QE 1 Photon 1 Electron Detector Noise (Primary Dark-Current) Electronic Noise: dominant!!

Overcoming the Electronic Noise Limit by Detecting SP DETECTOR LOAD ELECTRONICS Current Booster Process Detector Signal QE 1 Photon 1 Electron Detector Noise (Primary Dark-Current) Electronic Noise

Why Solid-State SP Micro-Detectors With respect to vacuum tube PhotoMultipliers (PMT) Typical microelectronic advantages: miniature size, low voltage, low power, rugged, reliable, suitable to integration, insensitive to magnetic fields and RF, etc. Improved basic performance: - inherently higher Photon Detection Efficiency over the Visible (V) and Infrared (IR) spectral range - comparable or lower noise (dark counting rate) - better photon timing

Micro-Detectors: Single Photon Avalanche Diode (SPAD) Devices and electronics SPAD Devices: Retrospect and Evolution From Device Physics to Detector Performance Active Quenching Circuit (AQC) SPADs for the Infrared Spectral Range

Current Booster Process in Micro-Detectors Avalanche multiplication of charge carriers by impact-ionization in reverse-biased p-n semiconductor junction can be either exploited in Linear amplifying mode Avalanche Photo Diodes APD or exploited in Trigger or Geiger Mode Single Photon Avalanche Diode SPAD

APD SPAD Avalanche PhotoDiode Single-Photon Avalanche Diode Bias: slightly BELOW breakdown Linear-mode: it s an AMPLIFIER Gain: limited < 1000 Bias: well ABOVE breakdown Geiger-mode: it s a TRIGGER device!! Gain: meaningless!!

SPAD Micro-Detectors: the Origin @ Shockley Laboratory in early 60 s : Avalanche Physics Investigation Basic insight Model of behavior above Breakdown Single-Photon pulses observed, but application limited by device features and quenching circuit! R.Haitz, J.Appl.Phys. 35, 1370 (1964) and 36, 3123 (1965)

for SPAD operation to avoid local Breakdown, i.e. mandatory edge breakdown guard-ring feature microplasmas uniform area, no precipitates etc. but for good SPAD performance......further requirements!!

Earlier Silicon Diode Structures Haitz s planar diode McIntyre s reach-through diode Thin SPAD Thick SPAD

PoliMi Si-SPAD PKI* Si-SPAD (SLIKTM ) Planar epitaxial structure typical active region: 10 to 100 µm diameter 1 µm thick Reach-Trough structure typical active region: 190 µm diameter 30 µm thick *Perkin Elmer Optoelectronics

Dark-Counting Rate (primary noise) Free Carrier Generation Generation - Recombination Centers Field-Assisted Generation

Carrier Trapping and Delayed Release Afterpulsing NB: minority carrier traps!!

Trapping and Afterpulsing operation @ lower temperature lower generation rate slower trap release hence primary dark-counting rate is reduced but afterpulsing is enhanced!! S.Cova, A.Lacaita, G.Ripamonti, IEEE Electron.Dev.Lett. 12, 685 (1991)

Low Detector Noise For low dark-counting rate Reduce GR center concentration Reduce Field-assisted generation For low afterpulsing probability Reduce deep level concentration (minority carrier traps) Reduce trapping and retriggering probability - Technology issues and device design issues - Wide sensitive area requires efficient gettering!!

Photon Detection Efficiency (PDE) Carrier Photogeneration And Avalanche Triggering!! higher excess bias voltage for higher PDE!! W.Oldham, P.Samuelson, P.Antognetti, IEEE Trans. Electron Devices ED-19, 1056 (1972)

Photon Detection Efficiency (PDE)

PDE - Detector Comparison Quantum efficiency, QE % 100 10 1 0.1 0.01 Planar SPAD PerkinElmer C4880-21 S25 PMT S1 PMT 200 400 600 800 1000 1200 Wavelength nm

Photon Timing

Photon Timing: Diffusion Tail carrier diffusion in neutral layer delay to avalanche triggering G.Ripamonti and S.Cova, Sol. State Electronics 28, 925 (1985)

Photon Timing: main peak width Statistical Fluctuations in the Avalanche Vertical Build-up (minor contribution) Lateral Propagation (major contribution) - via Multiplication-assisted diffusion A. Lacaita, M.Mastrapasqua et al, APL 57, 489 and El.Lett. 26, 2053 (1990) - via Photon-assisted propagation P.P.Webb, R.J.McIntyre RCA Eng. 27-3, 96 (1982); A.Lacaita et al, APL 62, 606 (1993)

Avalanche Lateral Propagation Multiplicationassisted Photon-assisted higher excess bias voltage improved time-resolution A. Spinelli, A. Lacaita, IEEE TED 44, 1931 (1997)

Photon Timing: SLIK TM reach-trough structure H.Dautet,..., R.J. McIntyre and P. Webb, Appl.Opt. 32, 3894 (1993)

Photon Timing: planar Epitaxial structure neutral p layer thickness w tail lifetime τ = w 2 / π 2 D n A.Lacaita, M.Ghioni, S.Cova, Electron. Lett. Electron.Lett. 25, 841 (1989)

Photon Timing comparison PerkinElmer SPCM, SLIK TM diode Planar SPAD

Reach-Through SLIK TM diode QE: 30%@500nm; 70%@700nm Dark Counts: 150 c/s FWHM: > 300ps Reach-Trough structure Typical active region: 200 µm diameter High voltage : 300 to 400V High dissipation Delicate and degradable Dedicated technology, high cost NOT COMPATIBLE with array detector and integrated circuits H.Dautet et al, Appl.Opt. 32, 3894 (1994)

Planar Single Photon Avalanche Diodes Planar structure typical active region: 20-100 µm diameter 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 integrated circuits Robust and reliable Low-cost A.Lacaita, M.Ghioni, S.Cova, Electron.Lett. 25, 841 (1989)

PoliMi Si SPAD Good QE and low noise Picosecond photon timing Low voltage : 15 to 40V Low power : cooler not necessary Standard Si substrate Planar fabrication process COMPATIBLE with array detector and IC s Robust and rugged Low-cost NEW COMMERCIAL SOURCE Reach-Through Si SPAD (SLIK TM ) Very good QE and low noise Sub-nanosecond photon timing High voltage : 300 to 400V High dissipation : Peltier cooler mandatory 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

Active Quenching Circuit (AQC) Micro Photon Devices, Via Stradivari 4, 39100 Bolzano, Italy, www.micro-photon-devices.com

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

Active quenching....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 5370e

Active Quenching Evolution Earlier modules in the 80 s Compact modules in the 90 s Integrated AQC today

iaqc: integrated Active Quenching Circuit Practical advantages Miniaturization mini-module detectors Low-Power Consumption portable modules Rugged and Reliable Plus improved performance Reduced Capacitance Improved Photon Timing Reduced Avalanche Charge Reduced Afterpulsing Reduced Photoemission reduced crosstalk in arrays F.Zappa, S.Cova, M.Ghioni, US patent 6,541,752 B2, 2003 (prior. March 9, 2000)

Signal pick-up for improved photon-timing 150 Tim e res olution FW H M (ps) 125 100 75 50 25 50 µm active area diameter Avalanche current sensing at very low level (< 100 µa) Can be added to any AQC 0 0 40 80 120 160 200 Threshold voltage (mv) S.Cova, M.Ghioni, F.Zappa, US patent No. 6,384,663 B2, 2002 (prior. March 9, 2000)

Recent advancement Wide active-area SPAD 100µm diameter 35 ps FWHM resolution at room temperature

Single Photon Counting & Timing Module Planar SPAD detector + iaqc + Timing pick-off network Compact and userfriendly Photon Detector Module (PDM)

SPAD Chip and Detector Module Silicon Chip Photon Detector Module

Easy to use Robust and Rugged Low power consumption Low cost Less than 50ps timing resolution Large area, up to 100µm diameter Photon Detection efficiency, 47% @ 532nm, 5V overvoltage www.micro-photon-devices.com

Comparison of Technology Technology Comparison Parameter SPAD & AQ circuit (MPD Technology) Integrated SPAD & passive quench Reach-Through SPAD Units Detector Diameter 20 to 100 20 to 50 200 µm Photon Detection Efficiencies @ 400nm 25 18 5 @ 532nm 47 35 40 % @ 650nm 35 25 65 Dark Counts 20um 50um 100um 250 typ (uncooled) 100 max (cooled) 1000 max (cooled) 50 max (cooled) 200 max (cooled) NA <100 Timing Resolution <50 40 300-600 ps After Pulsing 0.5 typ, 1.5 max 3 max 0.5 typ % Ma x Continuous Counting Rate 15 11,5 15 Mcps Arra y development Monolithic arrays possible, Monolithic arrays possible. 60 element array demonstrated. Large area arrays possible Monolithic arrays not possible Limited to 100-200 pixel with small pixels - TBD. arrays. MPD s photon counting module offer the best performance when fast timing resolution is required. cps MPD s technology provides Superior detection efficiency from 400 to 600nm

SPADs for the Infrared Spectral Range Micro Photon Devices, Via Stradivari 4, 39100 Bolzano, Italy, www.micro-photon-devices.com

Germanium SPAD devices Similar to silicon devices, but deep cooling mandatory (liquid nitrogen and lower) absorption edge shifts below 1500nm @ low temperature strong trapping effects strong field-assisted generation effects static situation of technology A.Lacaita, P.A.Francese, F.Zappa, S.Cova, Appl.Opt. 33, 6902 (1994)

InGaAs-InP SPAD devices

Photon Counting @ 1550nm Dark counting rate vs. temperature @ various overvoltages Dark counting rate vs. hold-off time @ various temperatures Counts (cps) 7x10 3 6x10 3 5x10 3 4x10 3 3x10 3 2x10 3 1x10 3 FWHM=65ps T = 200 K Detection Efficiency vs. Overvoltage @ various temperatures 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Time [ns] Timing Resolution Data obtained using Princeton Lightwave InGaAs SPADs

InGaAs-InP SPAD devices Complex device structure with heterojunctions Moderately deep cooling required (up to about 220K) Strong field-assisted generation effects Very strong trapping effects with very long release time Free-running operation with long deadtime (> 100micros) In practice limited to fast-gated operation Technology in evolution A.Lacaita, F.Zappa, S.Cova, P.Lovati, Appl.Opt. 35, 2986 (1996)

Application Cases Micro Photon Devices, Via Stradivari 4, 39100 Bolzano, Italy, www.micro-photon-devices.com

Outline Microsystems for Genetic Analysis Single Molecule Spectroscopy Adaptive Optic Systems Non-Invasive Testing of ULSI Circuits Quantum Cryptography (QKD)

Microsystems for DNA analysis Current trend system miniaturization minimal sample quantity low cost of operation Ultra high sensitivity required to the detector Valid for both Capillary Electrophoresis (CE) separation and Microarrays of DNA and Proteins

Capillary Electrophoresis (CE) for DNA fragment separation and analysis Electropherogram Intensity (a.u.) Time (min) DNA Fragment separation

Micro-Chip Electrophoresis (MCE) Injection Separation laser 8 cm

Looking inside the MCE apparatus... Compact & low-cost set-up with: Fully automated operation Laser diode excitation of fluorescence Controlled chip temperature Dual wavelength detection Dual HV power supply (0-5kV) Confocal optical sche me Remote control Problem debug via internet

...with a closer look to the Micro-Chip Holder

DNA fragment separation: MCE vs CE Separation of DNA fragments micro-sample in MCE set-up (100 s time scale) Separation of DNA fragments macroscopic sample in ordinary CE set-up (50 min time scale)

Sensitivity attained in MCE 80000 70000 60000 50000 40000 30000 20000 Static measure 5ng/ul 0,5ng/ul 0,05ng/ul C ounts [c /s] 1300 1200 1100 1000 900 800 700 100pM oligonucleotide labelled with CY 5 S/N=35 10000 0 181 161 141 121 101 81 61 41 21 1 600 500 400 300 0 50 100 150 200 Time [Sec.] CE Separation in glass microchip run buffer: TAPS-TRIS 100mM ph 8.5. Sample : 23 mer oligonucleotide labelled with CY 5 Detection limit @ S/N=3 : 1pM corresponds to < 30 molecules in the injection volume of 50pL

Microarrays An array is an orderly arrangement of probes with known identity which are used to determine complementary targets

DNA Microarrays vs Protein Microarrays DNA Microarrays: Very High number of spots > 10000 Sample Amplification by PCR Protein Microarrays: Moderate number of spots < 100 NO sample Amplification

SPAD Matrix Detector

High-Sensitivity Parallel Detection Basic goals - reduction of the acquisition time - miniaturization, lower system cost Photon Counting in Parallel FCS measurements in life sciences Single photon spectroscopy Adaptive optics in astronomy Photon Timing in Fluorescence lifetime imaging 3-D imaging with millimeter resolution

6x8 SPAD Matrix Detector 50 µm pixel diameter 240 µm pitch 4 interleaved sectors including 12 pixels with common anode sector 1 sector 2 sector 3 sector 4

2-D photon counting module Single pixel addressing 12 AQCs in parallel 20 bit counters Peltier cooling with digital temperature control Single bias supply (5V) Remote Full Control through USB port

2-D photon counting module Size 20cm x 8cm x 4cm

Single Molecule Spectroscopy Micro Photon Devices, Via Stradivari 4, 39100 Bolzano, Italy, www.micro-photon-devices.com

Single Molecule Spectroscopy Measurement on single molecules, not ensemble average Real-time measurement of molecule evolution Informations on the molecule dynamics Focus on molecules of biological interest : proteins FRET : Fluorescence Resonance Energy Transfer Nano-scale structural changes in single protein molecules

Idea of Sunney Xie and Haw Yang* (Harvard University): to probe Single-Molecule Protein Dynamics by a correlation analysis of fluctuations in real time of fluorescent photon delay with respect to laser excitation * H. Yang, G. Luo, P. Karnchanaphanurach, T.M. Louie, I. Rech, S.Cova, L. Xun, and X. Sunney Xie, SCIENCE ( 2003)

Single Photon Timing Module SPTM Compact (82x60x30mm) Single power supply (+15V) Controlled Temperature (Peltier cell) Software controlled settings On-board fast counters RS-232 data transmission I.Rech et al., IEEE J. of Sel. Topics in Quantum Electronics, vol.10, 788 (2004)

SPTM performance in the Harvard set-up Time-resolution: 60ps Dark Counts: down to 5 c/s Quantum Efficiency: 45% @ 500nm Instrumental Response Function (IRF) with SPTM and with PerkinElmer SPCM

Single Molecule Fluorescent Decay Single Fre FAD complex measured with SPTM (line). with PerkinElmer SPCM (circles) the shortest lifetime components are not resolved

Adaptive Optics Systems Micro Photon Devices, Via Stradivari 4, 39100 Bolzano, Italy, www.micro-photon-devices.com

STRAP Adaptive-Optics System of the VLT Observatory (Chile) European Southern Observatory - ESO D.Bonaccini et al, Proc. SPIE Vol. 3126, p. 580-588, Adaptive Optics and Applications; R.K.Tyson, R.Q.Fugate Eds., 1997 STRAP = System for Tip-tilt Removal with Avalanche Photodiodes collaboration: ESO - Microgate - PoliMi

Hybrid Quad- SPAD detector 2x2 lenslet array Spacer Ceramic Centering Ceramic 4 SPAD PerkinElmer SLIK Peltier 4 hybrid AQC 4 E 2 PROM

New development: Monolithic Quad- SPAD detector STRAP compatible geometry 100µm, 80µm, 50µm pixel diameter

New development: SPADA Wavefront Sensor SPADA: Single Photon Avalanche Diode Array collaboration PoliMi, IMM-CNR Bologna, UniPisa, Osservatorio di Catania, ESO F. Zappa, S.Tisa, P.Maccagnani, D.Bonaccini Calia, G.Bonanno, R.Saletti "Pushing Technologies: Single Photon Avalanche Diode Arrays" Proc. SPIE Vol. 5490, p. 1200-1210, Advancements in Adaptive Optics; D. Bonaccini Calia, B.L. Ellerbroek, R. Ragazzoni Ed.s, 2004

SPADA Chip Layout 60 element array with circular geometry plug-in compatible with MACAO 4 sets of pixels 20µm 50µm 75µm 35µm

SPADA detector head

SPADA Opto-Mechanical System Heptagon MACAO lenslet array WaveFront microlenses array microspheres held by ceramic holder SPADA sensor Peltier cooling stage No fibre coupling: higher reliability, lower losses, ruggedness, compatibility

SPADA system for AT SPADA Top metalic plate Detection Board USB RS232 2 SCSI cables (68 wires each) Interlock Gate Power supply cable (7 wires) power supply Mains (230V ac) re mote Computer MACAO equipment (by ESO) Seamless compatible with ESO MACAO sensor (electronics & optomechanical interfaces designed for CALDO and originally for AT-MACAO)

Detection board from the SPADA sensor Detection electronic board 1 2 3 60 iaqc iaqc iaqc iaqc gate hold-off duration diff.out diff.out diff.out diff.out diff. SCSI connector 68 pin SCSI connector 68 pin Gate In SMC to Data-Procesing Electronics or to MACAO equipment Operates the 60 SPADs through 60 iaqcs Outputs 60 channels differential lines directly to MACAO Controls SPADA settings Peltier e TermoR V high Peltier Controller Common anode supply T.meas T.set inter lock gate interlock µc Linear regulator -10V...-24V driver diff. overvoltage setting USB RS232 to Data-Processing board Interlock SMC Power supplies to remote computer of MACAO equipment +5V +12V -24V gnd +12VPeltier gndpeltier temperature, overvoltage, hold-off, gating Controls gates & interlocks Sends data directly to MACAO Sends data to Processing Board for stand-alone operation

AO Curvature Sensor and LGS layer sensing mode to Detection board from AO equipment from Data-Procesing Electronics SCSI connector 68 pin SCSI connector 68 pin Gate Out SMC Gate In SMC Ck diff. diff. 1 st A counter Enable Enable Ck 1 st B counter Enable Data Bus Shift Register Processing: A-B A+B Data shift clock FireWire for dat a uploading Curvature WaveFront Sensor Local Mode Operation On Board Curvature Signal computation possible to Detection board from AO equipment to AO equipment from AO equipment Membrane Load 4Ω 4W to Detection board +5V +12V -24V gnd +12VPeltier gndpeltier Interlock In SMC Interlock Out SMC LaserSynch In SMC LaserSynch Out SMC Sin. Out LEMO Power supplies Output GND diff. diff. diff. diff. Audio ampl. Timing and control logic 8bit sine peak Sine Generator 16bit sine table Power-supply for Detection board driver Power-supply for Data-Processing board FireWire for settings downloading RS232 to Detection board Mains 230V ac 3 km vertical resolution Sine wave generation for membrane mirror In/Out Synchronizations with pulsed laser Fast FireWire uploading

Fast Transient Phenomena from Data-Procesing Electronics SCSI connector 68 pin SCSI connecto r 6 8 pin Ck 1 st Counter Latch Enable Ck Ck 60 th Counter Latch Enable Ck Shift Register Shift Register Time slots: 10µs-100ms Measurement time: Time Windows: Enable Data Bus Data shift clock No blind-slots to Detection board from AO equipment Gate Out SMC Gate In SMC diff. diff. Timing and control logic FireWire FireWire for data uploading for settings downloading to Detection board from AO equipment to Detection board +5V +12V -24V gnd +12VPeltier gndpeltier Interlock In SMC Interlock Out SMC Power supplies diff. diff. driver Power-supply for Data-Processing board Power-supply for Detection board RS232 to Detection board Mains 230V ac Fast FireWire uploading

Fast Transient Imaging 10µsec-100msec i.t. Time tagging Continuos streaming Firewire link 12 bit data Experiment done at 20 kframe/s Pixels are illuminated by 1ms-period saw-tooth modulated light

Non-Invasive Testing of ULSI Circuits Micro Photon Devices, Via Stradivari 4, 39100 Bolzano, Italy, www.micro-photon-devices.com

Spontaneous Photon Emission in MOSFET Bulk p+ p Source n+ S Gate ox G hν Photon Emission Drain D hot-carriers High Electric Field Impact Ionization (Substrate current)

Light emission from CMOS inverters V IN V DD p-fet I S V OUT n-fet ph Arbitrary Units 5 4 3 2 1 V OUT N PH I S V IN 0 4.4 4.5 4.6 4.7 4.8 4.9 5.0 Time [ns]

Non-invasive Testing of Integrated Circuits Imaging detector locates e mitting MOSFETs Input objective hν SPAD Focusing objective (Timing detector) marks arrival time of single photons Photon Counts (a.u.) 180 160 140 120 100 80 60 40 20 Photons emitted by MOSFET Clock IN Data Out 1.9 ns 2 ns 0 6 8 10 12 14 16 18 20 22 Time [ns]

Single-Inverter transition Measured with SPAD Measured with PMT 120 100 Counts (a.u.) 80 60 40 FWHM = 50ps FWHM=250ps 20 0-0.1 0.0 0.1 0.2 0.3 0.4 Time [ns] F. Stellari et al, IEEE TED 48, 2830 (2001) J.C. Tsang et al., APL 70, 889 (1997)

Test example on a real circuit Transistor localization on the schematic and on the layout (LSM image) p-fet n-fet Laser Scanning Microscope (LSM) Spontaneous luminescence pulses synchronous with MOSFET switching Photon counts (a.u.) 1400 1200 1000 800 600 400 200 pfet nfet 28.3ps 0 2.0 2.5 3.0 3.5 4.0 4.5 Time [ns]

Example of defect localization by measuring dynamic waveforms Faulty Inverter Photon counts (a.u.) Photon counts (a.u.) 50 40 30 20 10 0 50 40 30 20 10 0 Faulty Inverter Good Inverter 5 10 15 20 Time [ns] 5 10 15 20 Time [ns]

Spatial Resolution microscope objectives 50x 5x single inverter teleobjective many inverters wide angle

Fast Ring Oscillator 2500 2000 1 cycle-time 32 Counts (a.u.) 1500 1000 500 0 0 50 100 150 200 250 300 350 400 450 50x Time [ns] on-chp device ECL comparator ring oscillator 1 2 46 47 counte r 32 1kΩ Electronics

Quantum Cryptography (QKD) Micro Photon Devices, Via Stradivari 4, 39100 Bolzano, Italy, www.micro-photon-devices.com

Quantum Key Distribution (QKD) principle

QKD system in free space transmission

QKD system in fibre transmission

Conclusions and Prospect - 1 SPADs in planar epitaxial Silicon technology offer high performance at low-cost; further improvements are under way (wider area SPAD; array detectors...) Monolithic iaqcs open the way to miniaturized modules (down to the chip scale) Remarkable results obtained in diversified applications: DNA and Protein Analysis; Single-Molecule Spectroscopy; Wavefront Sensors in Adaptive Optics; etc. The technology for infrared-sensitive SPAD devices is in evolution: significant progress may be expected in the near future

Conclusions and Prospect - 2 Results of decades of research made widely available by a new spinoff company

PoliMi Staff 2005 COVA, S. Full Professor GHIONI, M. Full Professor ZAPPA, F. Associate Professor RECH, I. Assistant Professor LABANCA, I. Research Associate GALLIVANONI, A. Research Associate TOSI, A. Post-Doc TISA, S. Ph.D. Student RESTELLI, A. Ph.D. Student GULINATTI, A. Ph.D. Student

Acknowledgments IMM-CNR, Bologna (I) - P. Maccagnani, A. Poggi, S. Solmi, M. Severi ICRM-CNR, Milano (I) - M. Chiari, M. Cretich ESO (D) D. Bonaccini Calia MICROGATE, Bolzano (I) - R. Biasi, A. Giudice HARVARD University (MA, USA) - X. Sunney Xie, H. Yang, G. Luo IBM Central Research (NY, USA) - J.C. Tsang, M. Mc Manus Heriot Watt Uni (UK) - G. Buller, S. Pellegrini, K. Gordon, V. Fernandez

MPD Company Overview Micro Photon Devices, Via Stradivari 4, 39100 Bolzano, Italy, www.micro-photon-devices.com

Vision and Markets Build a business that is the leader in Photon Counting Technologies by: Providing quality and reliable modules at a reasonable price. Attention to customer requirements Further developing the technology: ie: APD arrays, Higher efficiency in the red, 1550nm detection, APD+ASIC processing and tube technology. Markets Served: Universities, R&D facilities, Small OEM s Astronomy Adaptive Optics Biomedical DNA and Drug discovery, Confocal Microscopes, Particle Sizing. Quantum Cryptography InGaAs APD Custom applications

MPD Company Overview Electronic workshop Class 10000 clean room for integration Inventory and Production management 21 employees (with parent company Microgate Srl) 1350 square meters of area ISO certification in progress Close collaboration with state-of-the-art Silicon foundry PoliMi - Politecnico di Milano, DEI IEEE - LEOS DL 2005

Silicon Foundry Overview Permanent Staff: 49 Short Term Staff: 5 Associated Researchers: 30 Class 100 clean area (250 square meters) Pilot line for fabrication of devices and IC s in 4 silicon wafer Technological processes with high flexibility Consolidated know-how in Si device technology Si-micromachining and Si anodization

Management and Technical Team Roberto Biasi, CEO Micro-Photon-Device PhD in Aerospace Engineering at Politecnico di Milano in 1995. As founder and active partner of Microgate S.r.l., he has been involved as reaserch engineer and project manager in several leading projects in adaptive optics and telescope design, like MMT and LBT adaptive secondaries, ALMA antenna control system and STRAP, a tip-tilt adaptive optics control system based on Single Photon Avalanche Diodes. With this project he entered the field of photon counting and established a collaboration with the research team leaded by Prof.Cova at Politecnico di Milano. This collaboration brought to the foundation of Micro Photon De vices, a spin-off company spe cialized in production of single photon counting module s. Sergio Cova, CTO Micro-Photon-Device, Founder Born in 1938, doctor degree in Nuclear Engineering in 1962 at Politecnico di Milano, Italy, where he is Full Professor of Electronics since 1976. Fellow of the IEEE. Author of over a hundred and seventy papers in international refereed journals and conferences and of four international patents (US and Europe). He has given innovative contributions to research and development of photon detectors and associated electronics, nuclear electronics, microelectronic devices and circuits, electronic and optoelectronic measurement instrumentation and systems. He pioneered the development of Single-Photon Avalanche Diodes SPAD; he invented the Active-Quenching Circuit AQC, which opened the way to their application, and developed it up to monolithic integrated form; he devised and experimented new SPAD devices in silicon and in germanium and III-V semiconductors, thus pioneering the extension of photon counting techniques to the infrared spectral range. He collaborated to interdisciplinary research in physics, astronomy, cytology and DNA and protein analysis, developing dedicated electronic and optoele ctronic de vices and instrumentation. Massimo Ghioni, Technical Advisor, Founder Born in 1962, doctor degree in Nuclear Engineering in 1987 at Politecnico di Milano, Italy, where he is Full Professor of Electronics since 2000. He designed and experimented in his thesis work the first silicon Single-Photon Avalanche Diodes SPAD devices with epitaxial structure, demonstrating their picosecond photon timing performance. Visiting scientist in 1992 at the IBM T.J. Watson Research Center, Yorktown Heights, NY, USA, he developed a new CMOS compatible SOI photodetector for optical datacom applications. His current research interests are focused on the development of SPAD detectors and associated electronics for new microanalytical techniques in biomedical, genetic and diagnostic applications. He has worked in several leading research programs in international collaboration with universities, public bodies and high technology industries, such as Harvard University, USA; Heriot-Watt University, UK; ESO European Southern Observatory; Carl Zeiss, Jena, Germany; IBH, Glasgow, UK; Edinburgh Instruments, UK. He has published over eighty papers in international peer-reviewed journals and proceedings of international conferences and he is co-author of six US and European patents. Franco Zappa, Technical Advisor, Founder Born in 1965. Ph.D. in Electronics and Communications in 1993 at Politecnico di Milano, Italy, where he is Associate Professor of Electronics since 1998. His research interests are the design of single-photon avalanche photodiodes and related electronics for visible and near-infrared wavelength ranges, the design of photodetector arrays for imaging, and the non-invasive testing of VLSI circuits exploiting spontaneous hot-carrier luminescence emission. In 1994 he pioneered the first monolithic electronics for single-photon detection, designing the first integrated prototype ever reported in literature. He has published over sixty papers in international peer-reviewed journals and proceedings of international conferences and he is co-author of three US and European patents.

Product Portfolio Single photon counting modules with ultra-fast timing resolution and high photon detection efficiency. Active Quenching module which can be used with other SPAD s, for instance: InGaAs, HgCdTe and Silicon devices Custom modules and arrays can be developed using MPD s proprietary silicon SPAD devices and iaqc circuits

Summary of Capabilities MPD has a solid understanding of Photon Counting. Sergio Cova and his team have been working on Photon Counting for over 25 years, and have developed leading IP in active quenching and SPAD technology. MPD has developed a strong relationship with a state-of of-art Silicon Foundry. This will ensure a steady supply of SPAD s, and continuous improvements in SPAD performance. MPD has the infrastructure to be a solid OEM supplier and work closely with it s customers to develop custom solutions

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