1 / 16

Development of the first prototypes of Silicon Photomultiplier at ITC-irst

Development of the first prototypes of Silicon Photomultiplier at ITC-irst. N. Dinu , R. Battiston, M. Boscardin, F. Corsi, GF. Dalla Betta, A. Del Guerra, G. Llosa-Llacer, M. Ionica, G. Levi, S. Marcatili, C. Marzocca, C. Piemonte, G. Pignatel, A. Pozza, L. Quadrani, C. Sbarra, N. Zorzi

flavio
Download Presentation

Development of the first prototypes of Silicon Photomultiplier at ITC-irst

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Development of the first prototypes ofSilicon Photomultiplier at ITC-irst N. Dinu, R. Battiston, M. Boscardin, F. Corsi, GF. Dalla Betta, A. Del Guerra, G. Llosa-Llacer, M. Ionica, G. Levi, S. Marcatili, C. Marzocca, C. Piemonte, G. Pignatel, A. Pozza, L. Quadrani, C. Sbarra, N. Zorzi representing the INFN – ITC-irst collaboration for Development and Applications of SiPM to Medical Physics and Space Physics

  2. Outline • Motivations for new photon detectors • What is a Silicon PhotoMultiplier (SiPM)? • Characteristics of the first SiPM prototypes developed at ITC-irst • Summary and outlook Nicoleta Dinu

  3. Many fields of applications require photon detectors: • Astroparticle physics (detection of the radiation in space) • Nuclear medicine (medical imaging) • High energy physics (calorimetry) • Many others ..……… • Characteristics to be fulfilled by the photon detector candidate: • Highest possible photon detection efficiency • (blue –green sensitive) • High speed • High internal gain • Single photon counting resolution • Low power consumption • Robust, stable, compact • Insensitive to magnetic fields • Low cost Nicoleta Dinu

  4. A look on photon detectors characteristics Nicoleta Dinu

  5. Rquenching Current (a.u.) -Vbias Standardized output signal Time (a.u.) APDs in Geiger mode (GM-APD) • Quenching circuits development: • F. Zappa & all, Opt. Eng. J., 35 (1996) 938 • S. Cova & all, App. Opt. 35 (1996) 1956 Reach-through diode J.R. McIntire, IEEE Trans. El. Dev. ED-13 (1966) 164 Planar diode R. H. Haitz, J.App.Phys. Vol. 36, No. 10 (1965) 3123 The main disadvantage for many applications It is a binary device: One knows there was at least one electron/hole initiating the breakdown but not how many of them Nicoleta Dinu

  6. Front contact Out Current (a.u.) h Rquenching Two pixels fired Al Threepixels fired One pixel fired ARC n+ n pixels n+ p p  p+ silicon wafer Back contact Time (a.u.) - Vbias -Vbias What is a SiPM ? • matrix of n microcells in parallel • each microcell: GM-APD + Rquenching • Main inventors:V. M. Golovin and A. Sadygov • Russian patents 1996-2002 The advantage of the SiPM in comparison with GM-APD ANALOG DEVICE – the output signal is the sum of the signals from all fired pixels SiPM – photon detector candidate for many future applications Nicoleta Dinu

  7. Our activity for SiPM development • SiPM: INFN – ITC-irst research project • technological development of SiPM devices of 1 mm2 • matrix of few cm2 using SiPMs of 1 mm2 for Medical and Space Physics applications • Groups involved • ITC-irst – Institute for Scientific and Technological Research, Trento • simulations, design and layout • fabrication • electrical and functional characterization of the SiPM devices • INFN – Pisa, Perugia, Bologna, Bari, Trento branches • electrical and functional characterization of the SiPM devices • development of the read-out electronics • functional characterization of the system composed of SiPM and read-out electronics for medical (PET) and space (TOF) applications • 1.5 year activity • simulations, design and layout • first run fabrication • characterization of the first SiPM prototypes • the second run fabrication with optimised parameters finishes next week Nicoleta Dinu

  8. Simulations • Aim: to identify the most promising configuration for: • Doping layers • the optimum dopant concentration of the implants which gives a breakdown voltage • in the range 20 - 50 V • Layout design • to avoid breakdown developing at junctions borders • Optimum photon detection efficiency in the blue region • QE (wavelength dependent) optimisation • minimize the amount of light reflected by the Si surface • maximize the generation of e-h pair in the depletion region • avalanche optimisation • maximization of the breakdown initiation probability • geomoptimisation • minimize the dead area around each micro-cell (uniform breakdown and optical • isolation through trenches) Nicoleta Dinu

  9. Layout & Fabrication Process • Layout includes: • several SiPM designs with different implant geometries • test structures for process monitoring • test structures for analysis of the SiPM behavior • First fabrication run completed in September 2005 • Main characteristics: • p-type epitaxial substrate • n+ on p junctions • poly-silicon quenching resistance • anti-reflective coating optimized for short wavelength light Nicoleta Dinu

  10. Main block Wafer SiPM 1 mm 1 mm Wafer and SiPM design • SiPM geometric characteristics: • area: 1 x 1 mm2 • number of micro-cells: 625 • micro-cell size: 40 x 40 m2 Nicoleta Dinu

  11. Single micro-cell test structures VBD = 31 V SiPM (625 micro-cells) VBD = 31 V IV & breakdown • Uniform breakdown voltage VBD for different micro-cell and SiPM devices over the wafer • Uniform working point Vbiasfor different SiPM devices • Vbias= VBD + V, V  3 V • very important when matrix of many SiPMs devices of 1mm2 are built Nicoleta Dinu

  12. Single micro-cell test structures Quenching resistance • Uniform micro-cell quenching resistance over the wafer SiPM (625 micro-cells) • Uniform SiPM quenching resistance over the wafer • Very good correlation between Rmicro-cell and RSiPM Nicoleta Dinu

  13. rise time recovery time SiPM internal gain • Gain: • linear variable with Vbias • in the range 5x105 2x106 • micro-cell capacitance • Cmicro-cell = 48fF • micro-cell recovery time •  = Rquenching · Cmicro-cell~ 20 ns • Rise time •  1 ns (limited by the read-out • system) Nicoleta Dinu

  14. SiPM dark count • Room temperature (~ 23°C) • 1 p.e. dark count rate: ~ 3MHz • 3 p.e. dark count rate: ~ 1kHz • Mention: • trenches for the optical • isolation between micro-cells • were not implemented in the • first run 34.5 V 32.0 V 33.5 V 34.0 V 32.5 V 33.0 V • Dark count rate • linear variable with Vbias • increases with the temperature Nicoleta Dinu

  15. 4 p.e. 5 p.e. 3 p.e. 6 p.e. 2 p.e. 7 p.e. 1 p.e. 0 Excellent single photoelectron resolution Single photon counting capability • A LED was pulsed at low-light-level to record the single photoelectron spectrum Nicoleta Dinu

  16. Summary and outlook • SiPM - a research project of our INFN – ITC-irst collaboration team • Characteristics of the first SiPM prototypes developed by ITC-irst • SiPM area: 1 mm2, 625 micro-cells, size: 40 x 40 m2 • Uniform breakdown voltage (VBD~ 31 V)  uniform working point • Uniform micro-cell quenching resistance: Rquenching ~ 320 k • Fast signals (rise time ~ 1 ns, small recovery time  ~ 20 ns) • High internal gain, linear variable with the overvoltage: 5 x 105  2 x 106 • Dark count rate: ~ MHz @ 3 V overvoltage and room temperature • Excellent photon counting resolution • Outlook • The characterization of the prototypes is in progress……. • The second run fabrication with optimised parameters (dark count rate and optical cross-talk) finishes next week Nicoleta Dinu

More Related