1. Workpackage N° 4 1 Nanospad Review meeting Brussels, May 6 2008 Full Title: Single Photon Avalanche Diode (SPAD) per la lettura di Fibre Scintillanti Bando ASI per lo Sviluppo Tecnologico Coordinating person: Piera Maccagnani Partecipants: CNR-IMM, INAF-IASF Bologna, Poli-MI, Micro Photon Devices, Finanziamento richiesto: 300 k per 24 mesi Stato: ammesso al finanziamento Data di inizio: ???? FIBER-SPAD PROJECT Attività: realizzare rivelatori SPAD a grande area attiva (diametro di almeno 500 m) da interfacciare con fibre scintillanti. progetto e realizzazione dellelettronica non standard di acquisizione ed elaborazione del segnale. test delle prestazioni del sistema complessivo con sorgenti e fasci di particelle. Obiettivo: realizzazione di un rivelatore per raggi gamma basato su fibre scintillanti con lettura mediante Single Photon Avalanche Diode (SPAD).

2. Workpackage N° 4 2 Nanospad Review meeting Brussels, May 6 2008 Full Title: Protein microarray for enhanced diagnostics at low cost by integration of new technological developments 6FP – STREP Thematic Priority: IST-NMP-2 Bio-sensors for Diagnostic and Healthcare Coordinating person: Prof. Sergio Cova (MPD) Partecipants: Poli-MI, CNR-IMM e ICRM, CNRS, Univ. College Cork, Paul-Erlich Institut, Univ. Claude Bernard Lyon1 Finanziamento: 310 k per 30 mesi, 60 man months Durata: 1/12/2005 – 31/5/2009 NanoSPAD PROJECT Obiettivo: sviluppare uno strumento compatto per una diagnosi rapida e a basso costo delle allergie, basato su un micro-array biologico e su una matrice di rivelatori SPAD Attività IMM-BO: sviluppare una matrice di rivelatori SPAD da interfacciare al micro- array biologico (WP4)

3. Workpackage N° 4 3 Nanospad Review meeting Brussels, May 6 2008 Final objective: To develop a compact apparatus that can efficiently detect and measure arrays of proteins labeled with luminescent probes. The apparatus will employ a matrix of single-photon detectors (typically 48 detectors). Each element of the matrix is intended to measure the emission intensity from one of the micro-spots of the protein microarray. NanoSPAD PROJECT

4. Workpackage N° 4 4 Nanospad Review meeting Brussels, May 6 2008 Basic concept: use of an Array detector Target application: in-vitro allergy diagnosis with chemiluminescent protein microarray Optical implementation: Each spot of the microarray is conjugated to a SPAD pixel through a 1:1 imaging optics

5. Workpackage N° 4 5 Nanospad Review meeting Brussels, May 6 2008 Development of monolithic arrays of SPADs WP4 - Development of monolithic arrays of SPADs Matrix of SPAD detectors with wide pixel area 2x3mm 2 matrices with 48 SPAD elements, 240 m pitch matrix pixels with active area diameter of 50 m matrix geometry conjugated to that of the allergen microarray good performances obtained for single pixel-SPAD good SPAD performance uniformity inside the matrix 4 interleaved sectors including 12 pixels with common anode sector 1 sector 2 sector 3 sector 4

6. Workpackage N° 4 6 Nanospad Review meeting Brussels, May 6 2008 Detector noise sources: Thermal Carrier Generation (Dark Counting Rate, DCR) Carrier Trapping and Delayed Release (Afterpulsing effect) Reducing the Detector Noise For achieving low noise : Good quality substrates Clean processing Efficient GETTERING Reduced electric field

7. Workpackage N° 4 7 Nanospad Review meeting Brussels, May 6 2008 Improved Technological SPAD process isol field activex metal Implant to realize the p + doped region Process to oxidize the SPAD active area Gettering processes Different cleaning during technological process

8. Workpackage N° 4 8 Nanospad Review meeting Brussels, May 6 2008 Effect of CLEANING processes Main characteristic processes: active area oxidation doping of p + regions defects gettering process cleaning Uniform reduction of DCR @Tamb (21°C) Best DC reduced of 50% Plasma cleaning introduces defects in the SPAD active area.

9. Workpackage N° 4 9 Nanospad Review meeting Brussels, May 6 2008 Effect of IMPLANT process for p + regions Uniform reduction of DCR @Tamb (21°C) 5 times Implanting BF 2 we introduce defects in the SPAD active area. Probably due to Mo contamination. Main characteristic processes: active area oxidation doping of p + regions defects gettering process cleaning

10. Workpackage N° 4 10 Nanospad Review meeting Brussels, May 6 2008 Effect of OXIDATION process Same trend for the 2 oxides Same DC low level @Tamb LTO shows lower % of good devices Main characteristic processes: active area oxidation doping of p + regions defects gettering process cleaning

11. Workpackage N° 4 11 Nanospad Review meeting Brussels, May 6 2008 Effect of GETTERING process Same trend and behaviour of DC @Tamb NO CLEAR effect of the gettering process Main characteristic processes: active area oxidation doping of p + regions defects gettering process cleaning

12. Workpackage N° 4 12 Nanospad Review meeting Brussels, May 6 2008 OLD vs NEW Process Flow Higher % of devices with DCR<1kc/s @21°C: 44% in NEW Run vs 10% in the OLD Run NEW Run Best devices with 300-500 counts/s vs 700- 1000c/s from OLD Run Selected processes: Thermal oxidation Boron doping of p + regions Long gettering (5h) Wet cleaning

13. Workpackage N° 4 13 Nanospad Review meeting Brussels, May 6 2008 OLD vs NEW Process: large area SPAD OLD vs NEW Process: large area SPAD lower DCR confirmed also for 100 m SPAD Higher % of devices with DCR<5kc/s @21°C: 26% in NEW Run vs 7% for OLD Run NEW Run Best devices with a thousand counts/s vs thousands counts/s in the OLD Run

14. Workpackage N° 4 14 Nanospad Review meeting Brussels, May 6 2008 Wafer distribution map Full wafer characterization: 300 SPAD - 50 m 600 SPAD - 100 m Confirmed good fabrication yield for 50 and 100 m single SPAD Good uniformity in V BD values distribution: V BD =36.1V ± 0.5V Low detector noise: < 1kc/s for 45% of 50 m SPAD < 10kc/s for 70% of 50 m and 40% of 100 m SPAD < 100kc/s up to 200 m SPAD detection limit is not imposed by DCR of the detector NO COOLING required

15. Workpackage N° 4 15 Nanospad Review meeting Brussels, May 6 2008 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

16. Workpackage N° 4 16 Nanospad Review meeting Brussels, May 6 2008 Matrix Breakdown Voltage distribution All 48 pixels commonly working no blind zone in the matrix Good process control: new run: 36.2V ± 23mV old run: 37.9V ± 34mV Good uniformity obtained in: ­Photon detection efficiency ­Series resistance

17. Workpackage N° 4 17 Nanospad Review meeting Brussels, May 6 2008 Matrix Dark Counting Rate (DCR) Percentage of individual SPAD elements (horizontal scale) found within a given limit of the individual dark counting rate (vertical scale) measured for old and new SPAD matrix. Reduced DCR level confirmed also for the 50 m SPAD in the matrix: ­42% pixels with DCR<1 kc/s ­90% pixels with DCR < 10kc/s NO COOLING required for matrix operation in NanoSPAD project

18. Workpackage N° 4 18 Nanospad Review meeting Brussels, May 6 2008 Dark Counting Rate vs Temperature Dark count: combined effect of band-to-band tunneling (dotted line) and SRH generation (dashed line). The two contributions equals ~ -10°C reduced band-to-band contribution due to engineered profile for electric field better DC reduction lowering temperature very low DCR even @ 20°C due to cleanup and gettering processes in the active region Afterpulsing No AP @ 20°C with t H =250ns AP=1% @ 20°C with t H =70ns AP=1.5% @ -15°C t H =70ns

19. Workpackage N° 4 19 Nanospad Review meeting Brussels, May 6 2008 Matrix Photon Detection Efficiency 4% PDE spreading @530nm inside matrix (48 pixels) lower PDE value: @530nm 48-52% old vs 44-48% new Reduced thickness for the coating SiO 2 layer New run: PDE max = 48% @530nm PDE > 30% over visible range

20. Workpackage N° 4 20 Nanospad Review meeting Brussels, May 6 2008 Matrix PDE and Luminol Spectrum Luminol emission peak= 445nm SPAD PDE@445nm = 35÷38% quite good value Spectrum of chemiluminescence emitted following the catalysis of the reaction by the label.

21. Workpackage N° 4 21 Nanospad Review meeting Brussels, May 6 2008 WP4: Achievements – problems – further actions Achievements: Good performance SPAD matrices with 48 elements obtained in shorter time than planned (24 months instead of 30 months) Development of a NEW Process Flow for advanced SPAD devices: Improved performances obtained for single SPAD devices with 50 m diameter and for monolithic SPAD matrix with 48 detectors: ­low operating voltage: ~ 36V ­very uniform matrix breakdown voltage uniform PDE ­PDE >30% in the spectral range 500 – 700nm ­very low and uniform dark counting rate: 1kc/s for 45% matrix pixels no cooling required for matrix operation ­low afterpulsing effect: ~ 1% @ 20°C with t H =70ns ­reduced band-to-band tunneling due to low electric field profile better DC reduction at low temperature operation

22. Workpackage N° 4 22 Nanospad Review meeting Brussels, May 6 2008