WIXLIB

SPAD Pixel Detectors with HighTime ResolutionEdoardo CharbonTU Delft

Photons2

Not Only Intensity CountingTime-of-arrivalCorrelation3

Correlating PhotonsPolaritons in GaAsmicrocavity (λ 770nm)Green Hg line from Hg-Ardischarge lamp (λ 546nm)Young’ interference fringesBalili, Science 316, 1007 (2007)Photon statesIncoherentCoherentg(1)(0)01g(2)(0)11Thermal 124

Stellar Hanbury-Brown and TwissInterferometer5

Modern g(2) ImagerCMOS chip4x4 SPAD array10Hz dark count rate120dB dynamic range70ps resolution25% detection prob. On-chip electronics for digital outputsOff-chip processing (e.g. with digital oscilloscope)4x4 array: 120 HBT coincidence experiments running simultaneously6

Time-resolved Bioimaging Super-resolution Microscopy– Stimulated Emission Depletion (STED)– Single Plane Illumination Microscopy (SPIM)– Scanning Photoionization Microscopy (SPIM) Molecular Imaging– Fluorescence Lifetime Imaging Microscopy (FLIM)– Förster Resonant Energy Transfer (FRET)– Fluorescence Correlation Spectroscopy (FCS) Nuclear Medicine– Positron Emission Tomography (PET)– PET & Magnetic Resonance Imaging (MRI)– Single-photon Emission Computer Tomography (SPECT)7

Outline Single-Photon DetectionFrom Pixel to ImagerScaling Up ApplicationsThe Next Big Challenges8

Single-Photon Detection9

Single/few-photon Detectors Charge coupled devices (CCDs)Electron Multiplying CCDs (EMCCDs)Streak CamerasPhotomultiplier Tubes (PMTs)Multi/micro-channel plates (MCPs) Silicon Avalanche Photodiodes (SiAPDs) Single-Photon Avalanche Diodes (SPADs)10

Multiplication in Silicon Review:Photon to electron - Secondary electron - MultiplicationMultiplication in depletion region by impact ionizationp depletionregionReversebiasVn- n 11

Linear (or Proportional) Mode-IAVbdIAnp AvalancheVConventionalVopticalgain G High variability of gainFrom bias1Ve Vbd12V

Geiger Mode (SPAD)-IAVbdIAnp VGeigerAvalancheConventionalVopticalgain G Virtually infinite gain1Ve Vbd13V

Early SPAD Si Integration Reach-through APD (RAPD)– Vertical structure, thick device, high voltagesp πAbsorptionMcIntyre et al.Multiplicationpn Patterned double epitaxial APD (DJ-SPAD)– Planar structure, thin device, rel. low voltagesn Multiplicationp p-epin-substrateCova et al.14

Planar Processes p- guard ring for electric field reduction in edges Prevention of premature edge breakdown Creation of zone with constant electric fieldMultiplication regionp pn-wellp substrateElectric Field ξ15

Quenching the AvalanchePassive quenching:Operation cycle:VVop’Vop’photonarrivalDEAD TIMERqIAVSPADrechargeVVbdavalanchequenchingtDead time16

Controlling Dead TimeVphotonarrivalVop’VDEAD TIMESPADrechargeDead timetVbdavalanchequenching17

Double Threshold Active QuenchingNiclass, Thesis 200818

Salient Specs in SPADs Dead timeAfterpulsingDark countsPhoton detection probability (PDP)Timing resolution and in SPAD imagers Cross-talk PDP Uniformity19

Dark Counts: Dark Count RateMechanisms:–Band-to-band tunneling generation–Trap-assisted thermal generation–Trap/tunneling assisted generation State-of-the-art SPADs in dedicated technology:0.1 1Hz/µm2 State-of-the-art CMOS SPADs:1 10Hz/µm211Hz15x15250Hz50x503kHz20

Band-to-band TunnelingIneffective guard ring:Tunneling due to high dopingEffective guard ring:Low-probability tunneling21

Guard Ring Efficacy Ineffective guard ring Thus, high DCR Uniform multiplication zone Good prevention of prematureedge breakdownNiclass, Charbon, et al., JSTQE’07Gersbach, Charbon, et al., ESSDERC’0822

Dark Count RateNiclass et al. 200623

Photon Detection ProbabilityGersbach, Charbon, et al. SS Sensors 200924

Timing ResolutionPMT: 28psCMOS SPAD: 47ps[Becker & Hickl]25

From Pixel To Imager26

SPAD in CMOSVDDVOP’RQIAVDDdigitalpulseTQOUTVPassive quenching techniqueVOPDIGITAL DOMAIN27

Challenge Photocharges cannot be accumulated like inCCDs Photon pulses arrive when photons impingeHow to capture photon counting?How to capture photon arrivals? in parallel, on thousands ofpixels!28

Imaging: Three Architectures1.2.3.Random Access ReadoutEvent-driven ReadoutFully-parallel Processing29

1. Random Access Readout Pros– Simple Cons–––Highly inefficientLow frame rateEnormous number of photons lost!30

Random Access ReadoutGuard RingAnodeLogic GatesNiclass, Charbon, et al. JSSC 0531

First Massive SPAD Pixel ArrayNiclass, Charbon, ISSCC 0532

Photon Counting Uniformity Uniform counting at low, medium and high illumination33

Spatio-Temporal Uniformity7570FWHM/psTi:Sapphire femtosecond laserλ 470nmTAC resolution 4.88ps8065605550051015202530column number34

Cross-talk Electrical cross-talk reduced by potential barrierOptical cross-talk alleviated by reduced number of carriers in avalancheNiclass, Charbon, et al. JSSC 200535

Ultra-high Dynamic Range4µs10µs25µs100µs1ms36

2. Event-Driven ReadoutSPADSPADSPADCOLUMNSPADIDTDCID Pros– Ideal with low photon counts Cons– First photon of column detected– Large dead time37

LASP ArchitectureNiclass, Favi, Kluter, Gersbach, Charbon, ISSCC2008, JSSC 200838

LASP:First Fully Integrated Sensor32 Event-driven MUXes32 parallel TDCsR 70-500nsTP 97ps128x128 SPAD array6.4Gb/s I/OsNiclass, Favi, Kluter, Gersbach, Charbon, ISSCC 2008, JSSC 200839

TCSPC Test40

3D Imaging: Time-of-flight CamTime-of-flightpulsedlight sourceTOFmeasurement3D imagereconstructiontargetSingle-photonsensordd (c/2) TOF41

Three Dimensional ImagingAccuracy: 1mmFrame rate: 1HzDigital output42

3. Fully Parallel pply/Bias Lines43

Pros and Cons Pros– Full parallelism– No photons are lost within detection cycle Cons– Readout bandwidth– Substrate/supply noise44

MEGAFRAME:Massive Integration in DSMI/O 6 ArrayPrinciple of TDC32x16 ArrayPLL clockSTART O padsImplemented on 130nm CMOS45

Pixel SchematicThermometercoderVdd10b memoryColumndata busCalQuenching16 element delay lineSTARTSPADFF6b ripple counterGlobal STOPFrequency doublerGlobal clock280MHzDelay elementGersbach, Charbon, et al., ESSCIRC 2009Pitch: 50umMax. Resolution: 119psBandwidth: 1MS/sAccuracy: 1.2LSB (INL)Timing jitter: 128ps (FWHM)Timing uniformity: 2LSB46

Pixel LayoutOver 500 transistorsIn 50 x 50 µm247

TDC PerformanceDNLINL48

TDC Uniformity49

Dark Count RateMedian DCR: 100Hz50

Timing Jitter51

The MEGAFRAME32 Chip1.6mmPLLI2C32x32 pixelarray 1MS/s-pixel 100ps resolution 100ns range 1.2LSB precision 2LSB uniformityGersbach, Maruyama, Labonne, Richarson, Walker,Grant, Henderson, Borghetti, Stoppa, and Charbon,ESSCIRC 200952

Scaling Up Applications53

Less than 32 SPADs

Chemiluminescence ReactorGersbach, Maruyama, Sawada, Charbon, µTAS’0655

Chemiluminescence Reactor56

Chemiluminescence Reactor57

Integrated MicroreactorFluidic channelSPAD ArrayECL ReservoirSU8 channel reactorIgG ReservoirIn Situ Optical DetectionE. Charbon and Y. Maruyama,Springer, 201058

32 to 1024 Pixels

Two-photon FLIM SetupMode-lockedTi:SapphireLaser(740 920nm)AttenuatorDichroicBeam SplitterDetectorFilter(λ 488nm)TDCFluorescent sampleOn x/y tableHistogram processing60

Triple-exponential DecayFluorophore:Oregon Green Bapta-1Gersbach, Charbon, et al.,Optics Letters, 200961

Wide-field One-photon FLIMRahmadi Trimananda62

The Sample63Source: West Georgia Microscopic CenterBisaccate Pine Pollen (Magnification: 3200x)

Wide-field One-photon FLIM254msMarek Gersbach64

1024 to 20,000 Pixels

The Megaframe-128 ChipC. Veerappan, J. Richardson, R. Walker, D.-U. Li, M. W. Fishburn, Y. Maruyama,D. Stoppa, F. Borghetti, M. Gersbach, R.K. Henderson, E. Charbon, ISSCC2011

The Megaframe-128 Chip

The Megaframe-128 Chip50um pitch12.3mm11.0mm

Imager Block Diagram

Pixel ArchitectureMatt W. Fishburn

Photon CountingMatt W. Fishburn

Photon Time-of-ArrivalMatt W. Fishburn

TDC CharacterizationINLDNL55ps resolution, 55ns range

System-level Timing UncertaintyBlue laserRed laser

Cumulative Noise

Optical Burst Detection UniformityChockalingam Veerappan

MEGAFRAME Summary Format: 160x128 pixelsTiming resolution: 55psImpulse resp. fun.: 140psDCR (median): 50HzR/O speed: 250kfpsSize: 11.0 x 12.3 mm2

MultisensorChip Pitch: 25µm Single shot time res.:230ps Readout speed:40 2441fps PRNU:3.5%Y. Maruyama and E. Charbon,Transducers,Transducers 201178

Multisensor Principle Analysis– Electrochemical– Optical– CombinationopticalexcitationLabeled and label-lessDNA probesopticalanalysiselectrochemicalanalysis7979

DNA from Blood and UrineYuki Maruyama80

Point-of-care CycleYuki Maruyama81

Single-photon detection inMedical Applications

Positron Emission Tomography(PET)PMTscintillatorCoincidenceγ1mee AnnihilationMost commonly used:Fludeoxyglucose (18F)γ83

Positron Emission Tomography(PET)Source: SunCancerousGanglion84

The SPADnet ProjectObjective:Fully digital, scalable photonic component capableof detecting single and multi‐photon bursts, theirtime‐of‐arrival and intensityDETECTORCOMMUNICATIONDATA BUS85

The Innovation SPAD sensors with massively parallel chip-leveltime detection Large format with through-silicon-via basedpackaging Advanced optical coupling Network between sensors with high-speedmessage-passing Digital coincidence by hierarchical messagesnooping Novel image reconstruction exploiting spatialinformation86

The Impact Cheaper, simpler, scalable, robust PETs Higher levels of reliability Higher speed and flexibility in dataprocessing for imaging Full compatibility with MRI and otherimaging techniques Use of existing and new radiotracers withlow lifetime and high specificity will befeasible87

The Next Big Challenges88

Moore’s Law for Single-photon1M1 Mpixel0.8 CMOS0.35 CMOS512x256100 kpixel128x12810 kpixel160x12864x48130nmCMOS1 kpixel112x490nmCMOS128x232 pixel200320062009201289

Fill FactorGuard rings, design rules, on-pixelprocessing0.8µm CMOS0.35µm CMOS0.13µm CMOS90nm CMOS10µm?25µm59µmFF 1%15µmFF 9%FF 25%FF 35%90

How Far Are We from 1Mpx? Current minimum pitch: 15µm (0.13µm) 1024x1024 pixels: 16x16mm2 Assuming a minimum pitch of 10µm (90nm) 1024x1024 pixels: 11x11mm2Richardson et al., IISW 200915µµm91

Bioimaging Projects 2P FLIM (P. French, Imperial College, London) Fluorescence imaging in 9.4T MRI (with Prof. Rudin,ETH) SPIM*-FCS (with Prof. Langowski, Heidelberg) TIRF DNA probing (with COSMIC, Edinburgh) NIRI (with Dr. Wolf, USZ)92*Selective/Single Plane Illumination Microscopy

Other Medical Projects Intra-operative ß probe (CTI-Forimtech)Concept: wireless, disposable probe– Detect and localize small tumours or metastatic lymph nodes intraoperatively– Guide biopsy probe to tumour– Delineate tumour borders or invasion during operations– Search and localize tumourresiduals at the end of thesurgical interventionTarget: melanoma, pelvic tumours,mediastinoscopy93

Other Medical Projects (Cont.) Intra-operative sensors (EndoTOFPET-US, FP7 project)Concept: asymmetric PET with TOF– External SiPM plate– Endoscopic plate– Ultra-sound guidanceTarget: prostate, pancreasTumourExternal SiPMplate forcoincidenceRectal/intestinal Endoscope withMiniature detector array94

Conclusions Single-photon imagers are here to stayNew and old apps enabledNext challenges– More miniaturization– More parallelization– More flexibility– Novel imaging paradigms95

Acknowledgements96

http://cas.et.tudelft.nl

Logic Gates Guard Ring Anode Niclass, Charbon, et al. JSSC 05. 32 First Massive SPAD Pixel Array Niclass, Charbon, ISSCC 05. 33 . 32x32 pixel array I2C PLL 1.6mm 1MS/s-pixel 100ps resolution 100ns range 1.2LSB precision 2LSB uniformity The MEGAFRAME32 Chip. 53 Scaling Up Applications.