cmos-based single photon detectors and potential...

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CMOS-based

Single Photon

Detectors and

Potential ApplicationsDr A. Rochas, Project Leader, idQuantique SA (Switzerland)

A. Pauchard, O. Guinnard, L. Monat, and A. Matteo

2/21www.idquantique.com

Outline

- idQuantique presentation

- Motivations: limits of the present products, applications

- CMOS technology

- Single photon detector presentation

- Main features: - dead time,

- dark counts,

- afterpulsing,

- detection probability,

- timing resolution.

- Conclusion and Outlook


Company at a glance

Spun-out of University of Geneva in 2001

Strategic focus on opportunities offered by Quantum Photonics

Serve network security

and optical instrumentation markets


Optical Instrumentation

short pulse LASER source (850nm; 1.31µm; 1.55µm)

single photon counter: infrared (0.9µm to 1.6µm)

single photon counters: visible spectrum


The Present Limits

Silicon Single Photon Avalanche Diodes (Geiger Mode)Photomultiplier Tubes

High internal gain (106): single photon counting☺ ☺

Low noise level(dark counts and afterpulses)☺☺

Detection probability< 20% in the visible

Detection probability> 70% at λ = 650nm ☺

BUT:Difficult to integrate in arrays

Poor timing resolution: 500ps for PMTs, 350ps for SPADs Bulky, easily damaged


The Motivation

- a compact, solid-state,

single photon detector

- with low timing resolution

- and array integration capability.

Need for:


The Motivation

Single molecule detection: Fluorescence correlation spectroscopyor fluorescence decay time measurements

Laser ranging in space applications and telemetry

Quantum cryptography, random numbers generation

Optical fiber testing (Optical time domain reflectometry)

Laser diode characterization


Single Photon Detector

id100-20-MMFid100-20

Optical Fiber

InputFree Space

sensing part:CMOS (complementarymetal-oxide-semiconductor) chip


CMOS Technology

PC Microprocessor

- low cost fabrication- integration of electronic circuits on the same silicon chip with the SPADs- mature technology



100µmCO OUT

GND

VDD=+5V

CMOS chip

INN

INP

VREFRq

VH

- Geiger mode: VDD + VH > Vbd

- Passive quenching

Comparator QuenchingResistor

SPAD

VDD

Ve

VREF

OUT

Time


Comparator QuenchingResistor

SPAD

100µmCO OUT

GND

VDD=+5V

CMOS chip

INN

INP

VREFRq

VH

VDD

Ve

VREF

OUT

Low C


Time


Full Integration

Vop

npulse =C.Ve

q

Vbd

Time

IA Vop

Rq

C RdIA VVd

dead time ~ ∆trecharge α RqC

0

V

dead time < 70ns


The Noise

Unwanted counts:

- dark counts

- afterpulses


Trap-assisted

thermal generation

p+ undepleted region depletion region n-tub undepleted

region

z0 zw z

Ec

EV

TRAP

α process cleanliness: concentration and energylevel of traps

α temperature T

α excess bias voltage:probability for avalanchebreakdown


Dark Count Rate

At room temperature, for 20µm diameter:- typically < 200Hz- production yield > 90%

diameter

DCR α surface

yield

Cooling is required for larger SPADs or arrays


Afterpulsing

α process cleanliness: concentration and energy levelsof traps in the forbidden band

npulse =C.Ve

qα

Low C

p+ undepleted region depletion region n-tub undepleted

region

z0 zw z

Ec

EV

TRAP

α excess bias voltage:probability for avalanchebreakdown


Afterpulsing

Autocorrelation of a constant laser signalat a count rate of 10kHz

Becker and Hickl

Integral afterpulsing < 1%

At room temp, afterpulses in the first µs


Detection Probability

Peak in blue and decrease in the red / IR:CMOS process shallow depletion region width

junction close to the surfacep+

n

depletionregion

Photon Detection Probabilityλ=400nm, PDP=18%λ=500nm, PDP=35%λ=600nm, PDP=25%λ=700nm, PDP=20%λ=900nm, PDP=4%


Timing Resolution

p+

n

depletionregion

CMOS process: depletion region width ~1µm

40ps timing resolution (FWHM)

stable at high counting rate

Instrument Response Function at 5MHz, 2.7MHz, 62kHz


Conclusion

Technology CMOSDiameter 20µm / MMFDead Time 70ns (up to 15ns)

Detection Proba. up to 35% at 500nm

Dark Count Rate <200Hz at room T.Afterpulsing <1%

Timing Resolution 40ps FWHM / stable

id100-20

Free Space


Outlook

Large diameter single photon avalanche diodesCooling required

Development of application-oriented smart sensorsand smart sensors arrays32x32 SPADs array

smart: data processing, additional functionalities on the silicon chip

id150

by courtesy of E.Charbon-EPFL

1x10 SPADs array

cmos-based single photon detectors and potential...

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