Salvatore TudiscoSalvatore Tudisco
The new generation of SPADThe new generation of SPAD
Single Photon Avalanche Diodes Single Photon Avalanche Diodes arraysarrays
I Workshop on Photon Detection I Workshop on Photon Detection - - Perugia 2007Perugia 2007
LNSLNS
MicroelectronicsMicroelectronics
The collaboration The collaboration started in started in the 2004the 2004 to realise single to realise single device and first array device and first array prototypesprototypes
- - The Silicon PhotomultiplierThe Silicon Photomultiplier - - Arrays for imagingArrays for imaging
SPADSPAD
Si <100> Si <100>
cathodecathode
CMOS planar technologyCMOS planar technology
PP++
NN--
High Boron (PHigh Boron (P++) concentration ) concentration reduce the Breakdown voltagereduce the Breakdown voltage
Buried junctions pBuried junctions p---p-p+ + -n-n-- : :
• PP- - high Breakdown voltage high Breakdown voltage to prevent peripheral effects to prevent peripheral effects
• PP+ + to reduce the series resistance to reduce the series resistance substrate insulation substrate insulation integration of many elements integration of many elements
PP+ + sinkers: reduce the contact sinkers: reduce the contact resistance of the anode and provide a resistance of the anode and provide a low resistance path to the avalanche low resistance path to the avalanche currentcurrent
NN- - gettering region: impurities gettering region: impurities reductionreduction
E. Sciacca et al., IEEE Trans. on el. dev. 50 (2003) 4
E. Sciacca et al., IEEE Photonics Tech. Lett. 18 (2006) 15
p-n junction reversely biased above the p-n junction reversely biased above the breakdown voltagebreakdown voltage
1 1 m SiOm SiO22
Many elements integration Many elements integration simple quenching strategy simple quenching strategy
50 50
100 k100 k
Psasive QuenchingPsasive Quenching
SPAD SignalSPAD Signal
Rise time: 500 ps Rise time: 500 ps Fall time: 30 nsFall time: 30 nsRecovery time: Recovery time: 1,5 1,5 s s ((increase with Rincrease with RLL))
Important for the applications (SiPM)Important for the applications (SiPM)
SPAD PERPORMANCESSPAD PERPORMANCES Photodetection Efficiency Photodetection Efficiency Dark Counting RateDark Counting Rate TimingTiming Afterpulsing Afterpulsing
E. Sciacca et al., IEEE Trans. on el. dev. 50 (2003) 4
M. Belluso et al. Mem. SAIT Suppl. 9 (2006) 430M. Belluso et al. Mem. SAIT Suppl. 9 (2006) 430
Photodetection EfficiencyPhotodetection Efficiency
E.V. 10%E.V. 10%
SPAD PERPORMANCESSPAD PERPORMANCES Photodetection Efficiency Photodetection Efficiency Dark Counting RateDark Counting Rate TimingTiming Afterpulsing Afterpulsing
S. Privitera et al. submited to NIMAS. Privitera et al. submited to NIMA
d=20 d=20 m m
SPADSPAD countercounter
coolercooler
LaserLaser
SPAD2SPAD2
TDC TDC
TRIGGERTRIGGER
CH #CH #
SPAD1SPAD1CH #CH #
SPAD PERPORMANCESSPAD PERPORMANCES Photodetection Efficiency Photodetection Efficiency Dark Counting RateDark Counting Rate TimingTiming Afterpulsing Afterpulsing
laser pulselaser pulse 408 nm60 ps FWHM
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10,5 11 11,5
Time [ns]
Cou
nts
Many photons regimeMany photons regime
60 ps
Diffusion tail carrier diffusion in neutral carrier diffusion in neutral layer layer delay to avalanche trigger delay to avalanche trigger
S. Tudisco et al. S. Tudisco et al. Nuclear Physics B – proc. supl. 150(2006)317 Nuclear Physics B – proc. supl. 150(2006)317 Finocchiaro et al. Finocchiaro et al. IEEE Trans. on Nucl. Scie. 52(2005)3040IEEE Trans. on Nucl. Scie. 52(2005)3040
0
50
100
150
200
250
300
350
400
10 10,5 11 11,5 12
Time [ns]
Cou
nts
Single photon regimeSingle photon regime
120 ps
SPAD PERPORMANCESSPAD PERPORMANCES Photodetection Efficiency Photodetection Efficiency Dark Counting RateDark Counting Rate TimingTiming Afterpulsing Afterpulsing
Many photons regimeMany photons regimeSingle photon regimeSingle photon regime
laser pulselaser pulse 337 nm resolution 2 ns + dye for wave length-shift
SPAD PERPORMANCESSPAD PERPORMANCES Photodetection Efficiency Photodetection Efficiency Dark Counting RateDark Counting Rate TimingTiming Afterpulsing Afterpulsing
S. Privitera et al. Submit. To NIMAS. Privitera et al. Submit. To NIMA
uncorrelated dark countsuncorrelated dark counts
Distribution of successive Distribution of successive events to a primary events to a primary avalancheavalanche
Dark eventDark event
After-PulsesAfter-Pulses
Multi Hits Multi Hits TDC TDC
TRIGGERTRIGGER
CH #CH #
SPAD PERPORMANCESSPAD PERPORMANCES Photodetection Efficiency Photodetection Efficiency Dark Counting RateDark Counting Rate TimingTiming Afterpulsing Afterpulsing
Power law ?Power law ?
S. Privitera et al. submit. to NIMAS. Privitera et al. submit. to NIMA
the two contributions in the two contributions in 10 10 ss
After the subtraction of the After the subtraction of the uncorrelated dark backgrounduncorrelated dark background
SPAD ARRAY: SPAD ARRAY: 11stst prototype 5x5 prototype 5x5
AnodesAnodes
20 20 m diameter, 160 m diameter, 160 m pitchm pitch
Dark count rate distribution over 750 Dark count rate distribution over 750 pixels (30 arrays)pixels (30 arrays)
E. Sciacca E. Sciacca IEEE Photonics Technology Letters IEEE Photonics Technology Letters 18 (13-16) (2006) 163318 (13-16) (2006) 1633
SPAD ARRAYSPAD ARRAY
Optical Cross-TalkOptical Cross-Talkthe avalanche multiplication process the avalanche multiplication process produce photons produce photons
Isolation trenchIsolation trench
- 80 80 m attenuation lengthm attenuation length
- 1010-5-5 photons per carrier crossing the junction photons per carrier crossing the junction
Electrical Cross-TalkElectrical Cross-Talk A1A1
A5A52mV/div
100 mV/div
S. Privitera et al. submit. to NIMAS. Privitera et al. submit. to NIMA
11stst observation observation Induction; field fluctuations Induction; field fluctuations Common SubstrateCommon Substrate
SPAD ARRAYSPAD ARRAY
Time and Spatial correlationsTime and Spatial correlations
STARTSTART
Probability:Probability:Prompt Prompt 10 10-5-5
Delayed Delayed 10 10-3-3
Two contributions:Two contributions:Prompt < 2 ns Delayed 2 ns Prompt < 2 ns Delayed 2 ns 3 3 ss
Pixel 5-1Pixel 5-1
Piexls 4-1, 4-2, 4-3, 3-1, 1-1Piexls 4-1, 4-2, 4-3, 3-1, 1-1
Multi Hits Multi Hits TDC TDC
TRIGGERTRIGGER
CH #CH #
SPAD ARRAYSPAD ARRAY
Time and SpatialTime and Spatialcorrelationscorrelations
S. Privitera et al. Submit. to NIMAS. Privitera et al. Submit. to NIMA
-Cross-talk and Afterpulsing similar trend, Cross-talk and Afterpulsing similar trend, different slopdifferent slop
- No correlation with distancesNo correlation with distances
Afterpulses 5-1Afterpulses 5-1
Cross-Talk STOPCross-Talk STOP
RRLL
IIOUTOUT
VVAA
SPADSPAD
SiPM ConfigurationSiPM Configuration
OscilloscopioOscilloscopio
QDC or ADC channelsQDC or ADC channels
S. Privitera et al. submit. to NIMAS. Privitera et al. submit. to NIMA
A.Campisi et al. A.Campisi et al. NIM A 571 (1-2) (2007)350NIM A 571 (1-2) (2007)350
QDCQDC
ADCADCLaser Pulse Laser Pulse = 408 nm= 408 nm
FWHM = 50 psFWHM = 50 ps
Laser Pulse Laser Pulse = 408 nm= 408 nm
FWHM = 50 psFWHM = 50 ps
QDC channelsQDC channels
Montecarlo Montecarlo SimulationsSimulations
IncreasingIncreasing the probabilitythe probability
DecreasingDecreasing the dispersionthe dispersion
Event generatorEvent generatorn° fired pixelsn° fired pixelsparm. intensityparm. intensity
Pixel ONPixel ON
Cross-talk generatorCross-talk generatorparm. Probabilityparm. Probability
Cross-talk generatorCross-talk generatorparm. dispersionparm. dispersion
Fill the spectrumFill the spectrum
Single device performancesSingle device performances (20 (20m)m)
• PDEPDE: : ~ 45% @ 550 nm~ 45% @ 550 nm
• Dark counting rateDark counting rate: : ~ ~ 400 cps @ 25 °C, 400 cps @ 25 °C, ~ ~ 100 cps @ 15°C 20100 cps @ 15°C 20
• TimingTiming:: ~ 160 ps many-photons regime, ~ 300 ps single photon regime~ 160 ps many-photons regime, ~ 300 ps single photon regime
• AfterpulsingAfterpulsing: : ~ ~ 1010-3-3 pulses for primary avalanche pulses for primary avalanche
LimitationsLimitations::
• full recoveryfull recovery ~~ 1,5 1,5 ss
5X5 Array performances5X5 Array performances (20 (20m)m)
• Dark Counts uniformityDark Counts uniformity: : ~ 10%~ 10%
• Cross-TalkCross-Talk: prompt: prompt ~ ~ 1010-5-5 pulses for trigger pulses for trigger
delayeddelayed ~ ~ 1010-3-3 pulses for trigger pulses for trigger
No distance dependenceNo distance dependence
• SiPM configurationSiPM configuration:: poor resolution poor resolution
peak sensing (ADC) better then charge sensing (QDC)peak sensing (ADC) better then charge sensing (QDC)
ConclusionConclusion
2007 - 12007 - 1stst SiPM prototype ( SiPM prototype (~~ 5000 pixels), 1 5000 pixels), 1stst array for imaging array for imaging