Team: Salvatore Lombardo, Sebania Libertino, Stefania Privitera, CNR-IMM, Catania
The Silicon Single Photon Avalanche Detectors (SPADs) and the Silicon Photomultipliers (SiPMs) are both based on the concept of the avalanche photodiode (APD) operated in Geiger mode. In particular, the SiPM is a pixelated photodetector of APDs, while the SPAD is essentially the single pixel version. In the SiPM the pixels, APDs with integrated resistances in series, are connected in parallel trough a metal grid, and reverse biased at a voltage higher than the breakdown voltage. The detection principle is based on the photon absorption, followed by the triggering of an avalanche breakdown which gives raise to a fast current pulse, proportional in amplitude to the number of fired pixels. Compared to the other semiconductor photodetectors the SiPM presents major advantages of sensitivity, high internal gain, and speed of response. Compared to PMTs the SiPM is much more compact, easy to handle, much lower operating voltage, mechanically robust, optically resistant, and electrically reliable.
We will realize a number of systems based on Silicon Photomultipliers for bio-medical applications. This activity is done in close collaboration with STMicroelectronics. In particular, the targeted applications are Near InfraRed Spectroscopy (NIRS) and Near InfraRed Imaging (NIRI), to be used for hemoglobin oxidation level real time monitoring, imaging of human brain cortex, and photoplethysmography (PPG). The activity will be performed in the framework of the European Project "ASTONISH", which has been approved by the ECESEL JU and it has started on June, 1, 2016.
The figure shows on top the evolution of the SPAD / SiPM technology, with a continuous reduction of defect density to improve dark count rate and avalanche breakdown uniformity. On the bottom we show the phantom emulating the human head with skin, skull, cortex, and the raw signal detected by a SiPM at a source-to-detector distance of 6 cm for a 735 nm light pump operated at a few mW. Excellent signal to noise ratio is demonstrated.
We plan to extend further such devices both in terms of performance and in terms of fields of application.
Selected Papers
Improvement of sensitivity in continuous wave near infra-red spectroscopy systems by using silicon photomultipliers, Roberto Pagano, Sebania Libertino, Delfo Sanfilippo, Giorgio Fallica, and Salvatore Lombardo, 1 Mar 2016 | Vol. 7, No. 3 | DOI:10.1364/BOE.7.001183, BIOMEDICAL OPTICS EXPRESS 1183
Pagano, R; Lombardo, S; Palumbo, F; Sanfilippo, D; Valvo, G; Fallica, G; Libertino, S, Radiation hardness of silicon photomultipliers under Co-60 gamma-ray irradiation, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 2014, 767, 347-352, 10.1016/j.nima.2014.08.028
Pagano, R.; Valvo, G.; Sanfilippo, D.; Libertino, S.; Corso, D.; Fallica, P. G.; Lombardo, S., Silicon photomultiplier device architecture with dark current improved to the ultimate physical limit, APPLIED PHYSICS LETTERS, 102, 10.1063/1.4804192, 2013
Pagano, Roberto; Corso, Domenico; Lombardo, Salvatore; Valvo, Giuseppina; Sanfilippo, Delfo Nunzio; Fallica, Giogio; Libertino, Sebania, Dark Current in Silicon Photomultiplier Pixels: Data and Model, IEEE TRANSACTIONS ON ELECTRON DEVICES, 59, 2410, 10.1109/TED.2012.2205689, 2012
Sciacca, Emilio; Condorelli, G.; Aurite, S.; Lombardo, S.; Mazzillo, M.; Sanfilippo, D.; Fallica, G.; Rimini, E., Crosstalk characterization in Geiger-mode avalanche photodiode arrays, IEEE ELECTRON DEVICE LETTERS, 29, 218, 10.1109/LED.2007.915373, 2008
Mazzillo, M.; Condorelli, G.; Campisi, A.; Sciacca, E.; Belluso, M.; Billotta, S.; Sanfilippo, D.; Fallica, G.; Cosentino, L.; Finocchiaro, P.; Musumeci, F.; Privitera, S.; Tudisco, S.; Lombardo, S.; Rimini, E.; Bonanno, G., Single photon avalanche photodiodes arrays, SENSORS AND ACTUATORS A-PHYSICAL, 138, 306, 10.1016/j.sna.2007.05.016, 2007
Sciacca, E.; Lombardo, S.; Mazzillo, M.; Condorelli, G.; Sanfilippo, D.; Contissa, A.; Belluso, M.; Torrisi, F.; Billotta, S.; Campisi, A.; Cosentino, L.; Piazza, A.; Fallica, G.; Finocchiaro, P.; Musumeci, F.; Privitera, S.; Tudisco, S.; Bonanno, G.; Rimini, E., Arrays of Geiger mode avalanche photodiodes, IEEE PHOTONICS TECHNOLOGY LETTERS, 18, 1633, 10.1109/LPT.2006.879576, 2006
Finocchiaro, P; Campisi, A; Corso, D; Cosentino, L; Fallica, G; Lombardo, S; Mazzillo, M; Musumeci, F; Piazza, A; Privitera, G; Privitera, S; Rimini, E; Sanfilippo, D; Sciacca, E; Scordino, A; Tudisco, S, Test of scintillator readout with single photon avalanche photodiodes, IEEE TRANSACTIONS ON NUCLEAR SCIENCE, 52, 3040, 10.1109/TNS.2005.862912, 2005
Finocchiaro, P; Cosentino, L; Fallica, G; Lombardo, S; Mazzillo, M; Musumeci, F; Piazza, A; Privitera, G; Privitera, S; Rimini, E; Sanfilippo, D; Sciacca, E; Scordino, A; Tudisco, S, Test of scintillator readout with single photon avalanche photodiodes, 2004 IEEE Nuclear Science Symposium Conference Record, Vols 1-7, 1274, 2004
Sciacca, E; Giudice, AC; Sanfilippo, D; Lombardo, S; Zappa, F; Cosentino, R; Mazzillo, M; Ghioni, M; Fallica, G; Belluso, M; Bonanno, G; Cova, S; Riminia, E, Silicon planar technology for single-photon optical detectors, OPTICAL SENSING, 5459, 227, 10.1117/12.545026, 2004
Sciacca, E; Giudice, AC; Sanfilippo, D; Zappa, F; Lombardo, S; Consentino, R; Di Franco, C; Ghioni, M; Fallica, G; Bonanno, G; Cova, S; Rimini, E, Silicon planar technology for single-photon optical detectors (vol 50, pg 918, 2003), IEEE TRANSACTIONS ON ELECTRON DEVICES, 50, 1819, 10.1109/TED.2003.816567, 2003