1. LAL – RAPA- Sept 2008 Vincent CHAUMAT Présentation SiPM. Sommaire : 1- Vue d’ensemble des photo-détecteurs 2- Généralités sur les SiPMs. 3- Caractérisation. - en continue - en dynamique - sous lumière 4- Applications actuelles et futures. - merci à Nicoleta & Véronique pour l’aide qu’elles m’ont fourni.

2. LAL – RAPA- Sept 2008 Vincent CHAUMAT A look on photon detectors characteristics VACUUM TECHNOLOGY SOLID-STATE TECHNOLOGY PMTMCP-PMTHPDPN, PINAPDGM-APD Photon detection efficiency Blue20 % 70 %50 % Green-yellow40 % 80-90 %60-70 % Red  6 % 80 % Timing / 10 ph.e  100 ps  10 ps  100 ps few nstens of ps Gain10 6 - 10 7 3 - 8x10 3 1  200 V 10 5 - 10 6 Operation voltage1 kV3 kV20 kV100-500V  100 V Operation in the magnetic field  10 -3 T Axial magnetic field  2 T Axial magnetic field  4 T No sensitivity Threshold sensitivity (S/N  1) 1 ph.e  100 ph.e  10 ph.e  1 ph.e Shape characteristicssensible bulky compactsensible, bulky robust, compact, mechanically rugged VACUUM TECHNOLOGY SOLID-STATE TECHNOLOGY PMTMCP-PMTHPDPN, PINAPDGM-APD Photon detection efficiency Blue20 % 60 %50 %30% Green-yellow40 % 80-90 %60-70 %50% Red  6 % 90-100 %80 %40% Timing / 10 ph.e  100 ps  10 ps  100 ps tens nsfew nstens of ps Gain10 6 - 10 7 3 - 8x10 3 1  200 10 5 - 10 6 Operation voltage1 kV3 kV20 kV10-100V100-500V  100 V Operation in the magnetic field  10 -3 T Axial magnetic field  2 T Axial magnetic field  4 T No sensitivity Threshold sensitivity (S/N  1) 1 ph.e  100 ph.e  10 ph.e  1 ph.e Shape characteristicssensible bulky compactsensible, bulky robust, compact, mechanically rugged

3. LAL – RAPA- Sept 2008 Vincent CHAUMAT PIN, APD & GM-APD PINAPDGM-APD N-Type Silicon Depletion region P + active area P-N junction edge p-n junction p-n junction, V bias < V BD p-n junction, V bias > V BD Gain = 1 Gain = M (~ 50-500) - linear mode operation- Gain → infinite -Geiger-mode operation- P + - Type N – Type Silicon p + -type silicon (substrate) p - -type epitaxial layer p+p+ n+n+

4. LAL – RAPA- Sept 2008 Vincent CHAUMAT Des GM-APD aux SiPM Current (a.u.) Time (a.u.) Standardized output signal p + -type silicon (substrate) p - -type epitaxial layer p+p+ n+n+ One pixel fired Two pixels fired Three pixels fired Current (a.u.) Time (a.u.) Al ARC -V bias Back contact p n+n+n+n+ p n+n+n+n+  R quenching h p + silicon wafer Front contact - V bias n pixels GM-APD R quench GM-APD – ne donne pas d’information sur l’intensité lumineuse SiPM (présenté dans les années 90 par Zadigov et Golovin) –Matrice de µ pixel en parallèle / chaque pixel = GM-APD + R quench –Le signal de sortie est proportionnel au nombre de pixels déclanchés Out R quenching -V bias

5. LAL – RAPA- Sept 2008 Vincent CHAUMAT Différents design de SiPM -1 FBK (Italie) Geometric characteristics: area: 1 x 1 mm 2 625 pixels /40 x 40  m 2 pixel size Hamamatsu (Japon) Geometric characteristics area: 1 x 1 mm 100 pixels /100 x 100  m 2 pixel size 40 µm 100 µm 1 mm Front-side illumination Poly-silicon resistor Photos done at LAL mechanical service, thanks to B. Leluan

6. LAL – RAPA- Sept 2008 Vincent CHAUMAT Différents design de SiPM -2 Photonique (Russie) Geometric characteristics area 1x1 mm 2 556 pixels /  43 x 43 µm 2 pixel size Zecotec (Russie) Geometric characteristics area 1.08 x 1.08mm 2 (  1,17 mm 2 ) 1050 pixels/ ~ 33 x 33 µm 2 pixel size 43 µm Front-side illumination Metal-resistive-semiconductor 33 µm

7. LAL – RAPA- Sept 2008 Vincent CHAUMAT –Static characteristics breakdown voltage leakage current quenching resistance –Dynamic characteristics time structure of the output signal (e.g. rise time, recovery time) gain capacitance noise (e.g. thermal generation, afterpulses, optical cross-talk estimation) –Light characteristics photon detection efficiency v.s. wavelength (e.g. white lamp and monocromator) response linearity v.s. incident optical power density (e.g. dynamic range) One set-up for measurements in dark conditions Based on the hypothesis that the signal generated by an absorbed photon (the real signal) or by a thermal generated carrier (dark count signal) are identical, the AC characterization can be done studying the dark signals One set-up for measurements in the presence of the light Listes des paramètres caractérisés

8. LAL – RAPA- Sept 2008 Vincent CHAUMAT The set-up for the tests in dark conditions Hardware: - amplifier - MITEQ – 0,01-500 MHz / 50  / 45dB gain / 5mV RMS noise - Fisher Bioblock climatic chamber -10 to +50°C, PC temperature controlled through RS232 - Keithley Source Meter 2611 (V max = 200V, I sensibility  2 pA, connections through triaxial cables) - home-made counter with variable threshold on the input signal - TDS 5054 oscilloscope (500 MHz, 5 GS/s) - Pt100 ohm thermometer read by an Keithley 2700 data acquisition system Software: - automatic IV and dark rate measurements by LabView program and C ++ program - gain, afterpulses & cross-talk analysis by LabView program - automatic monitoring of the Pt100 thermometer by LabView software

9. LAL – RAPA- Sept 2008 Vincent CHAUMAT Static characteristics IV reverse characteristic (25°C): -Pre-breakdown current -carriers generated both in the bulk and surface depleted region -linear with V bias -Post-breakdown current -determined by the dark events and the charges carried by each event (gain) -parabola with V bias -V BD  34V @ 25°C -I post BD  1µA @  V=4V -IV forward characteristic (25°C) -exponential behavior given by the diode equivalent resistor -linear behavior given by the quenching resistor R SiPM ~ 555  R Q pixel = R SiPM * 625 pixels ~ 350 k  V BD

10. LAL – RAPA- Sept 2008 Vincent CHAUMAT Temperature dependence static characteristics 10°C 25°C 20°C 15°C V BD growths with the temperature  V BD ~ 80 mV/°C  ~ 0,25% / °C Diminution du courant d’obscurité avec la température à overvoltage constant.

11. LAL – RAPA- Sept 2008 Vincent CHAUMAT SiPM signal shape Shape avalanche photon unique Fall time: qq nS (limité par les instruments de mesure) Recovery time: ~50nS

12. LAL – RAPA- Sept 2008 Vincent CHAUMAT SiPM gain Defined as the charge developed in one pixel by a primary charge carrier: Linear increasing with the bias voltage the triggering probability increases linear with the bias voltage Pixel capacitance – the slope of the linear fit gain v.s. bias voltage G ~ 1,2 x 10 6 @ V bias = 37 V G ~ 1,6 x 10 6 @ V bias = 38 V C pixel ~ 50 fF

13. LAL – RAPA- Sept 2008 Vincent CHAUMAT Gain temperature dependence Gain decreases with the temperature at fixed reversed bias  G ~ 0,3 x 10 5 / °C  ~ 3% / °C 15°C 10°C 20°C 25°C Gain invariant avec la température à overvoltage constant

14. LAL – RAPA- Sept 2008 Vincent CHAUMAT SiPM noise -1 Dark count rate –the main source of noise limiting the SiPM performances –the number of false photon counts/ second registered by the SiPM in the absence of the light –three main contributions: thermally – through Shockley-Read-Hall generation-recombination centers afterpulses – carriers trapped during the avalanche discharging and release after, triggering a new avalanche optical cross-talk – during an avalanche discharge, photons are emitted – these photons can trigger an avalanche in an adjacent cell dark signals s – single pixel pulse (thermal generated) d – double pixel pulse (optical cross-talk) a – pulses with small amplitude, following a single or a double pulse (afterpulses)

15. LAL – RAPA- Sept 2008 Vincent CHAUMAT SiPM noise -2 Dark count rate (0,5 pe. threshold) ~ 2 MHz @ V bias = 37 V (  V= 3V) ~ 3 MHz @ V bias = 38 V (  V= 4V)

16. LAL – RAPA- Sept 2008 Vincent CHAUMAT QE – the quantum efficiency probability that a photon generate an e/h pair in the active region of the device (e.g. n + /p junction of a pixel) - wavelength dependent P triggering – the avalanche efficiency probability that an electron generate an avalanche in the device (e.g. Π region of a pixel) – voltage dependent ε geom – the geometrical efficiency Active surface to total surface ratio  Traditional PDE:  PDE of the SiPM: Photon detection efficiency of the SiPM p + -type silicon (substrate) p - -type epitaxial layer p+p+ n+n+

17. LAL – RAPA- Sept 2008 Vincent CHAUMAT Set-up for tests in light conditions  Principle method for the PDE measurement:  low incident flux (~ 10 7 incident photons /s/mm²) – to avoid the SiPM saturation  the number of the incident photons – evaluated with a calibrated photodiode  the number of the photons recorded by the SiPM – evaluated by two methods: DC method: (I under illumination - I dark )/G mean expDC method: (I under illumination - I dark )/G mean exp G exp mean – the exp. average value of the gain determined from the charge distributionG exp mean – the exp. average value of the gain determined from the charge distribution AC counting method: N signals under illumination – N signals darkAC counting method: N signals under illumination – N signals dark with particular attention on the acquisition parameters to eliminate the afterpulses and the cross-talkwith particular attention on the acquisition parameters to eliminate the afterpulses and the cross-talk  a good agreement (within 5%) has been found in between the two methods 3D translation tables Calibratedphotodiode SiPM Grating monochromator Optical bench CCD camera X Z Y Data acquisition system Halogen light source Halogen light source 350-800nm (100W)

18. LAL – RAPA- Sept 2008 Vincent CHAUMAT PDE

19. LAL – RAPA- Sept 2008 Vincent CHAUMAT Linéarité

20. LAL – RAPA- Sept 2008 Vincent CHAUMAT Applications & future T2K (usine à neutrino) 50000 SiPMs utilisés sur 5 détecteurs ILC calorimetre hadronique (étude) Biologie: Pet détection, fluorescence, life time mesurement, etc… Plus grande surface active (9mm²) par pixel Matrice de SiPM-FBK -SensL …. (bonne efficacité géométrique, résolution position 2D, accroissement des surfaces de détecteurs)

21. LAL – RAPA- Sept 2008 Vincent CHAUMAT Slides supplémentaires

22. LAL – RAPA- Sept 2008 Vincent CHAUMAT Model of GM – APD & passive quenching (1) Pioneering work done in the 1960 to model micro-plasma instabilities –RCA company by J. R. McIntire, IEEE Trans. Electron Devices, ED-13 (1996) 164 –Shockley Research Laboratory by R. H. Haitz, J. App.. Phys. Vol. 36, No. 10 (1965) 3123 First order circuit model of the GM-APD with passive quenching Diode –R s – diode series impedance (~ 1 k  ) –C d – total junction capacitance –V BD – breakdown voltage –S – random on-off switching of the avalanche discharge Biasing circuit –R Q – quenching resistance (> 100 k  ) –V bias – bias voltage CDCD RSRS V BD RQRQ V BIAS DIODE S

23. LAL – RAPA- Sept 2008 Vincent CHAUMAT S CDCD RQRQ V BIAS RSRS V BD OFF condition –No charge traversing the breakdown region –S – open –C d – charged to V bias –i ~ 0 through R q ON condition –Avalanche discharge triggered by a carrier generated in the breakdown region (e.g. photon or thermal carrier) –S – closed –C d discharge to V BD with a time constant R s x C D –Diode current increases to (V bias – V BD) /R Q (R Q >> R s ) –Diode voltage decreases from V bias to V BD OFF condition –S – open –C d – recharge again to V bias with a time constant R Q x C d ready for a new detection DIODE Model of GM – APD & passive quenching (2) current time t0t0 t1t1 t2t2 V BD V bias time V i max ~(V bias – V BD )/R Q

24. LAL – RAPA- Sept 2008 Vincent CHAUMAT FBT W20 distribution charge Charge moyenne 37.5V : 332fC Charge photon unique 37.5 V : 239fC Charge moyenne 36.5V : 216fC Charge photon unique 36.5 V : 169fC Charge moyenne 35.5V : 227fC Charge photon unique 35.5 V : 114fC Charge photon unique Charge mean :

25. LAL – RAPA- Sept 2008 Vincent CHAUMAT SiPM noise -3 Dark count rate (0,5 pe. threshold) ~ 2 MHz @ V bias = 37 V (  V= 3V) ~ 3 MHz @ V bias = 38 V (  V= 4V) Dark signals single pixel pulse (thermal generated) two simultaneous pixels pulse (optical cross-talk) pulses with smaller charge, following a single or a double pulse (afterpulses)