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