CMOS ImagElectronic Cam

DJet PropJet Prop

California Instit

ge Sensors:mera-on-a-Chip

Dr. Eric R. Fossumpulsion Laboratorypulsion Laboratorytute of Technology

OUTLOUTL

Quick look at state of tApplication driversApplication driversHistorical perspectiveM d CMOS iModern CMOS image Integration of electroniCamera-on-a-chip and

LINELINE

he art

i lsensor pixelscs

d smart sensors

256x256 CWith on Chip TimingWith on-Chip Timing

Clock

+5V

CMOS APSand Control Circuitsand Control Circuits

Analog

Nixon and Fossum, 1995

AT&T/JPL 1024AT&T/JPL 1024 x

ChiChip

Dickinson

1024 CMOS APS1024 CMOS APS

Closeup of pixels

n, Ackland, Azadet, Inglis, Mendis, Jones and Fossum 1995

Historical PeHistorical Peon Image g

erspectiveerspectiveCapturep

A long long tA long long t

Cave painting from

time agotime ago. . .

m 12,000 years ago

A few hundredA few hundred

Capturing images with paintwith paintTormented soul f ’from Michelangelo’s Last Judgment (1 41)(1541)

d years agod years ago. . .

Film PhotFilm Phottographytography

1960’ S lid St t

1963 Morrison Honey

1960’s Solid-State

1963 Morrison - Honey» Light spot position “com

1964 H t t l IB1964 Horton, et al. - IB» The “scanistor”

1966 Schuster & Strull» 50 x 50 element phototp

1967 Weckler - Fairchi» Charge integration on a» Charge integration on a

I C t

ywell

e Image Capture

ywellmputational” sensorBMBM

- Westinghousetransistor arrayyilda floating pn junctiona floating pn junction

1960’ S lid St t1960’s Solid-State

1967 Weimer, et al. - R» 180x180 TFT element s180x180 TFT element s» Battery powered, wirele

1968 Dyck & Weckler -1968 Dyck & Weckler -» “Passive pixel” photodio» 100 x 100 element arra» 100 x 100 element arra

I C te Image Capture

RCAself-scanned sensorself scanned sensoress camera- Fairchild- Fairchildode array (“reticon”)

ayay

1960’ S lid St t1960’s Solid-State

1968 Noble - Plessey» Passive pixel photodiodPassive pixel photodiod» On-chip charge integra» Buried photodiode struc» Buried photodiode struc» Source-follower buffer i

Birth of active pixel phoBirth of active pixel pho

I C te Image Capture

de arrayde arrayting amplifiercturecturein pixelotodiode arrayotodiode array

1970’ S lid St t1970’s Solid-State

1970 Boyle, Smith, AmAT&T Bell Labs» Charge-coupled semico

Birth of the CCDBirth of the CCDAlmost the end of MOS

I C te Image Capture

melio, Tompsett

onductor devices

S image sensors

CCDs WeCCDs We

Smaller pixel sizesLower readout noiLower readout noiNo fixed pattern noL hiLow on-chip poweInteresting device

ere Betterere Better

s (3 electrodes/pixel)seseoise

di i tier dissipationphysics

CCDs Are a MatCCDs Are a Mat

DALSA 25 MpiDALSA 25 Mpi

ture Technologyture Technology

xel sensorxel sensor

HDTV imageHST imageHST image

CCDs HaveCCDs HaveRequires high charge tRequires high charge t» Special fabrication proc

L lt i d» Large voltage swings, d» Radiation “soft” in spac

Difficult to integrate ondrive and signal chain Serial access to imageSystem power in 1-10System power in 1 10

Limitations Limitationstransfer efficiencytransfer efficiencycessdiff t lt l ldifferent voltage levelsce environment-chip timing, control, electronics

e dataWatt rangeWatt range

Total CCD CameTotal CCD Came

CCD imaging syoff chip componoff-chip compon

era Power is Highera Power is High

ystems require many entsents

Connectrix cameraConnectrix boardsConnectrix boards

1970’s an1970 s an

Very little published acHitachi Matsushita ReHitachi, Matsushita, Redevelopment of passivNHK/Olympus developNHK/Olympus developCaltech develops retin

nd 1980’snd 1980 s

ctivity on MOS imagerseticon continuedeticon continued

ve pixel MOS imagerped photodiode type APSped photodiode type APSa-like sensors

CMOS ImagCMOS Imag

How Do ThHow Do Th

ge Sensorsge Sensors

hey Work?hey Work?

CMOS ImagCMOS Imag

Charge Integra» Passive Pixel S» Active Pixel Se

Non-IntegratingNon Integrating» Retina-like Sen» Other function» Other function

ge Sensorsge Sensors

ating SensorsSensorsensorsg Sensorsg Sensorsnsorsss

PassivePassive

1 transistor per pixel10 L scaling - small pixels(10 μm pixel needs 1.0 μmprocess)Great QEGreat QEPoor noise (250 e- rms)Poor scaling for large g gformatsPoor scaling for fast

d treadout

e Pixelse Pixels

s TX

m

COL BUS

Evolution of FEvolution of F100

CCD Invented10

Size

(um

)

CCD Invented

1Feature Si

0.11970 1975 1980 1985

Enough space to pu

Feature SizeFeature Size

Pixel Size

DiffractionLimitLimit

ze

5 1990 1995 2000 2005

Year

t amplifier into each pixel.

PhotodiodePhotodiode

3 transistors per pixel15 L scaling (10 μm pixel

d 0 7 )needs 0.7 μm process)Great QEOK noise (50-100 e- rms)OK noise (50-100 e- rms)Good scaling for large arrGood scaling for fast arrag

Active PixelActive Pixel

VDD

)

RST

)rays

ays

RS

y

COL BUS

NHK chip / closeupNHK cross sectionNHK cross sectionNHK high speed imagees

Photogate APhotogate A

5 transistor pixel20 L scaling (10 μm pixel need0 5 )0.5 μm process)QE loss due to poly gateGreat noise (10 e- rms)Great noise (10 e- rms)Good scaling for large arraysGood scaling for fast arraysg y

Active PixelActive PixelVDD

ds RST

PG TX

RST

RS

COL BUSCOL BUS

CMOS APSCMOS APS

RowSelectL iLogic

Timingand Control

CoDigital CoDigital Output

ArchitectureArchitecture

Pixel Arrayy

Analog SignalAnalog SignalProcessorsColumn-Parallel

lumn Select

Analog-to-DigitalConverters

lumn Select

JPL 256x256JPL 256x256

Pixel size: 20.4 μmPixel type: photogate

Array size: 2Timing contrPixel type: photogate

Fill factor: 21%Technology: HP 1.2 μm

n-well

Timing, contrFPN suppresMotion detecWindow readn-well Window readProgram. inte

6 CMOS APS6 CMOS APS

56x256rol CDS

Conv. Gain: 10.6 μV/e-Saturation: 800 mVrol, CDS

ssionctiondout

Saturation: 800 mVNoise: 13 e- rmsFPN: 0.15% satDyn range: 76 dBdout

egration timeDyn. range: 76 dBPower: 3 mW

Motion DMotion D

U fl ti diff iNormalMotion to left

Use floating diffusion aNo change to pixel de

DetectionDetection

l fl image Motion to right

as analog frame memorysign, just timing

AT&T/JPL 1024AT&T/JPL 1024 x

ChiChip

Dickinson

1024 CMOS APS1024 CMOS APS

Closeup of pixels

n, Ackland, Azadet, Inglis, Mendis, Jones and Fossum 1995

Kodak/JPL PPKodak/JPL PP

• Pinned photodiode CMOS AP• No poly obscuration• Good blue response• Lower dark current• 256 x256 element sensor

P. Lee, R. G

D CMOS APSD CMOS APS

PS

Pinned photodiode (PPD) APS pixels

Gee, M. Guidash, T. Lee, and E. Fossum, 1995

QuantumQuantum

0.6

0.7nt

um E

ffici

ency

0 3

0.4

0.5

Qua

n

0.1

0.2

0.3

Wavele

400 500 600 7000.0

QE competit

EfficiencyEfficiency

AR128N5-1

AR128N2-6

AR128P1-6AR128P1 6

Cassini 381 (FF)

AT&T

CC128A

TI VP (FF)

KAI-0370

FT8

FOTOS 128

CC128B

CC256B

ength (nm)

800 900 1000 1100

tive with CCDs

CMOS APS LowCMOS APS Low

Single 5V supply operaLow capacitance on-chLow capacitance on chPixel amplifier activateC l ll l i lColumn-parallel signalfrequency and low currDigital output simplifiesTotal chip power 10-50p p

Power AdvantagePower Advantage

ation (or 3.3 V)hip loadship loadsed only for readout

h i t t l chains operate at low rent bias (<10 μA)s off-chip drivers0 mW

CMOS ImagCMOS Imag

On-Chip FOn Chip F

ge Sensorsge Sensors

FunctionalityFunctionality

CMOS FunctionCMOS FunctionOn chip timing and coOn-chip timing and coOn-chip analog signa» Correlated double sam» Fixed pattern noise su» Local neighborhood im» Compression preproc

On-chip analog-to-digOn-chip DSP and digOn chip DSP and dig

nality Advantagenality Advantageontrol circuitsontrol circuits

al processingmplinguppressionmage processingcessinggital conversiongital sensor controlgital sensor control

JPL/AT&T DigitJPL/AT&T Digit

176x144 ELEMENTSPIXEL ARRAY

176x144 ELEMENTSPIXEL ARRAY

tal CMOS APStal CMOS APS

176x144 elements20 μm pixel pitch Single-slope ADC per column176 ADCs per chip8 bit resolution35 mW at 30 Hz3.5 volt supply

Mendis, Inglis, Dickinson, and Fossum 1995

CMOS Sensor andCMOS Sensor and

2

3OO

IVP’s MAPP 2200

d Image Processord Image Processor

256x256 elementPassive pixelPassive pixel 32 μm pitchO hi ADCOn-chip ADCBit-slice image processor150 mm2 chip sizep

Forchheimer, Ingelhag, and Jansson 1992

VLSI vision burglar alaarm/modem

JPL MultiresoJPL MultiresoProcess:

Pixel pitcNo. pixelPwr suppSaturatioImaging SaturatioConv. gaNoise:

Dynamic

Imaging Array

DynamicRange:FPN:

Power:Di it l

Analog

at 30HzDigitalControl

lution Sensorlution Sensor: HP 1.2 um

n ell CMOSn-well CMOSch: 24 umls: 128 x 128py: 5 voltson: 1200 mVon: 1200 mVain: 8 uV/e-

116 uV rms15 e- rms

c 80 dBc 80 dB

<3 mV p-p<2.5 %< 5 mW

Full resolution image4x4 Averaged image (left)

1/4 Subsampled image (right)p g ( g )

Kemeny, Panicacci, Pain, Matthies, Fossum 1995

JPL High SpeeJPL High Spee

AnalogAnalog

Pixel ArrayPixel Array

DigitalDigital

TimingTiming

DigitalDigital

ed CMOS APSed CMOS APS

128x128 elementsPhotodiode active pixels16 μm pixel pitch Analog output (top)1-bit Digital output (bottom)8,000 frames per second, pOn-chip timing and control

Panicacci, Jones, Fossum 1994

JPL High SpeeJPL High Spee

Analog Image

ed CMOS APSed CMOS APS

Binary Image

Pixel Level FPixel-Level F

St f d U i itStanford University» Pixel level oversam

University of Tokyo» Pixel level compres

Carnegie-Mellon U» Pixel level pixel so» Pixel level pixel so

California Institute » Retina like function» Retina-like function

FunctionalityFunctionality

G ly - Gamalmpled ADCo - Aizawassion logic

University - Kanaderting logicrting logicof Technology - Mead

nsns

FabricatioFabricatioOpaque silicides nOpaque silicides - nDark current - more

d imemory devicesCollection depth - SCapacitor implants Low voltages - reduLow voltages reduand dynamic rangeLow 1/f noise transLow 1/f noise trans

on Issueson Issuesneed silicide maskneed silicide maske sensitive than

SOI is a problemare nice

uced amplifier swinguced amplifier swing eistors helpistors help

ScalingScaling

3540

ns)

202530

ize

(mic

ron

51015

Pixe

l Si

00 0.5 1

Design Rule (L

g Trendg Trend

20L

JPLAT&T/JPLNHK

10L

VVL

Profit Zone

1.5 2

L, microns)

Miniaturized CMMiniaturized CMMOS APS CamerasMOS APS CamerasTechnology demonstration cameraTechnology demonstration camera• 256x256 CMOS APS Camera• Full digital interface• Electronic pan and zoom

Next demonstration camera• On-chip ADC• Automatic exposure control• Automatic exposure control

ConcluConcluCMOS APS has aCMOS APS has a“respectability” in CMOS image senCMOS image senadvantages for:

S t i i t i» System miniaturiz» Low power portab

F i li» Functionality vs. cExpect significant share and creation

usionsusionsachievedachieved performance

nsors offer significantnsors offer significant

tizationble applicationscostgrowth in market

n of new markets

AcknowleAcknowle

JPL Advanced Image SPlane Technology GrogyNational Aeronautics aAdministration - OfficeAdministration Office and TechnologyAdvanced Research PAdvanced Research PLow Power Electronics

edgmentsedgments

Sensor and Focal-ouppand Space

of Space Accessof Space Access

Projects AgencyProjects Agency -s Program