SPAD SIPM Final Presentation rr - Hamamatsu …...6OLGH 2XWOLQH 6L30 DQG 63$' ,QWURGXFWLRQ WR 31 MXQFWLRQ GHYLFHV )XQGDPHQWDOV RI VLQJOH SKRWRQ DYDODQFKH SKRWRGLRGH 63$' )XQGDPHQWDOV

Slide # 1

SiPM and SPAD:Emerging Applications for Single-Photon Detection

Slawomir S. Piatek, Ph.D.Senior University Lecturer of PhysicsNew Jersey Institute of Technology

Slide # 2

SiPM and SPAD: emerging applications

Slawomir Piatek

NJIT/Hamamatsu

Copyright 2019 Hamamatsu

Slide # 3

Outline

1/17/2019 SiPM and SPAD

• Introduction to PN junction devices

• Fundamentals of single-photon avalanche photodiode (SPAD)

• Fundamentals of silicon photomultiplier (SiPM)

• Key opto-electronic characteristics of SiPMs

• Applications of SiPMs and SPADs

• Summary and conclusions

Slide # 41/17/2019

Introduction to PN junction devices

SiPM and SPAD

Slide # 5

Terminology

1/17/2019

PD – Photodiode

APD – Avalanche photodiode

SPAD – Single-photon avalanche photodiode

SiPM – Silicon photomultiplier

MPPC – Multi-pixel photon counter; another name for SiPM

PMT – Photomultiplier tube

SiPM and SPAD

The same

SPPC – Single-pixel photon counter; another name for SPAD The same

Slide # 6

Generic PN junction: modes of operation

1/17/2019

I

V

VBD

linear mode APDoperates in this region

PD operates inthis region

≈≈

SPAD and SiPMoperate in this region

Breakdown voltage

V

I

Gei

ger

regi

on

SiPM and SPAD

Dark current versus bias voltage

Slide # 7

PD, APD, and SPAD

1/17/2019

hν

p

n

Vbias

PD

hν

p

n

Vbias

APD

hν

p

n

Vbias

SPAD

1 γ −> 1 pair 1 γ −> ~100 pairs 1 γ −> “∞” pairs

VBD

V

I VBD

V

IVBD

V

I

SiPM and SPAD

Slide # 81/17/2019

Single-photon avalanche photodiode

(SPAD)

SiPM and SPAD

Slide # 9

Structure of a SPAD

1/17/2019

Figures from Zappa et al. 2007

Structure of a thick SPAD Structure of a thin SPAD. This structure is used in SPAD arrays.

SiPM and SPAD

Slide # 10

Operation of a SPAD

1/17/2019

SPAD

photonVBIAS > VBD

time

curr

ent

avalanche starts here

Once triggered, the avalancheis perpetual; however, the SPADis no longer sensitive to light.

Without quenching, SPAD operates as a light switch.

SiPM and SPAD

Slide # 11

Operation of a SPAD (passive quenching)

1/17/2019

VBIAS

RQ

RS

SPAD

RQ >> RS

ISPD

VSPAD

VBIAS

RQ

VBD VBIAS

steady state

transient

quench

recharge

RQ must be large enough to ensure quenching.

quasi-stable “ready”state

photon

SiPM and SPAD

Slide # 12

Operation of SPAD (passive quenching)

1/17/2019

VBIAS

RQ

RS

SPAD

RQ >> RS

VS

time

quench

τr ~RQ.CJ (recovery characteristic time)

10s – 100s of ns

recovery

(quench resistor)

(load resistor)

SiPM and SPAD

Voltage pulse on Rs due to avalanche

Slide # 131/17/2019

Silicon photomultiplier(SiPM)

SiPM and SPAD

Slide # 14

Silicon photomultiplier: structure

1/17/2019

Anode

Cathode

=

SPAD

RQ

p+

π

n+

p+

oxide

Single microcell

Electrical equivalent circuit of a microcell

Side

vie

wTo

p vi

ew

Each microcell is a SPAD in series with a quench resistor. All microcells are connected in parallel. SiPM is not an imaging device because all microcells share a common current summing node.

SiPM and SPAD

Slide # 15

Silicon photomultiplier: operation

1/17/2019

VBIAS > VBD

K

A×G

R

time [ns]

Am

plit

ude

[mV

]

Example of single-photoelectron waveform (1 p.e.)

Gain = area under the curve in electrons

Overvoltage, ΔV = VBIAS - VBD

SiPM and SPAD

Slide # 16

Silicon photomultiplier: modes of operation

1/17/2019

VBIAS

1, 2, 3,….

VBIAS

If the pulses are distinguishable, SiPM can be operated in a photon counting mode.

If the pulses overlap, the SiPM can be operated in an analog mode. The measured output is voltage or current.

counter

SiPM V or I

0 100

light

SiPM and SPAD

Slide # 171/17/2019

Key opto-electronic characteristics of SiPMs

SiPM and SPAD

Slide # 18

Structural and geometrical considerations

1/17/2019

Active area: w×h; ranges from 1×1 mm2 to 6×6 mm2

Microcell area: ranges from 10×10 μm2 to 100×100 μm2

Pitch: center-to-center distance

Geometrical fill factor: fraction of a μ-cell sensitive to light, ~30% to ~ 80%

w

h

μ-cell

pitch

w

h

μ-cellsensitive to light

SiPM and SPAD

Slide # 19

Packaging

1/17/2019

Ceramic Surface mount Metal, TE-cooled Array of SiPMs

SiPM and SPAD

Slide # 20

Gain

1/17/2019

Gai

n×

105

1

2

3

4

5

0

Overvoltage [V]

0 2 4 6 8

Gai

n×

106

0

4

8

12

16

Overvoltage [V]

0 2 4 6 8 10

75×75 μm210×10 & 15×15 μm2 S13360-6075PE

SiPM and SPAD

Gain depends linearly on overvoltage. For a given overvoltage, gain depends on the μ-cell size.

Slide # 21

Photon detection efficiency (PDE)

1/17/2019

PD

E [

%]

0

10

20

30

40

50

Wavelength [nm]

200 400 600 800 1000

Overvoltage [V]P

DE

[%

]

0

10

20

30

40

0 2 4 6 8 10

SiPM and SPAD

Probability that the incident photon is detected. PDE is a function of wavelength and overvoltage.For a given overvoltage, PDE depends on the μ-cell area.

Slide # 22

Dark current and dark count rate

1/17/2019

-5 0 5 10 1510-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4S13720

1.3×1.3 mm2

25×25 μm2

2668 μ-cells

Recommended overvoltage: 7 V

ID = 10-7 A

DCR = ID/(μe) ≈ 570,000 cps

Gain (μ) = 1.1×106

DCR/μ-cell = 213 cps

Overvoltage [V]

Dar

k cu

rren

t [A

]

SiPM and SPAD

Slide # 23

Crosstalk

1/17/2019

primary avalancheor discharge

secondary avalanchesor crosstalk

μ-cell

Photon emitted during an avalanche.

~30 photons with Eγ > 1.14 eV (μ=106)

time

1 p.e.

3 p.e.

3A

AVol

tage

SiPM and SPAD

Slide # 24

Crosstalk probability

1/17/2019

0 2 4 6 8 10

Overvoltage [V]

0

10

20

30

40

Cro

ssta

lk p

roba

bili

ty [

%]

S13360

25×25 μm2

0 2 4 6 8 10

Overvoltage [V]

0

20

40

60

8075×75 μm2

S13360

Cro

ssta

lk p

roba

bili

ty [

%]

Crosstalk probability depends on overvoltage and microcell size (gain).

SiPM and SPAD

Slide # 25

Linearity and dynamic range

1/17/2019

10-12 10-11 10-10 10-9 10-8 10-7 10-6 10-510-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

10-0

Incident light level [W]

Out

put c

urre

nt [

A]

25×25 μm2

2668 μ-cells

S13720

10-8 W implies 3.7×10-12 W per μ-cell

which is ~16×106 photons per second per μ-cell

which is ~1 photon per 63 ns

SiPM and SPAD

For a given active area, the number of μ-cells determines the upper limit of the dynamic range.

Slide # 26

Tradeoffs


μ-cell size

Fixed: active area & overvoltage; change μ-cell size

Slide # 27

Tradeoffs


Overvoltage

Fixed: active area & μ-cell size; change overvoltage

Slide # 281/17/2019

Applications

• Time-of-flight LiDAR

• Flash LiDAR

• Flow cytometry

• Bio- and chemiluminescence

• Dark matter detection

SiPM and SPAD

Slide # 29

Photodetector comparison

1/17/2019

PMT APD SiPM

Quantum efficiency Up to ~40% Up to ~85% Up to ~50%

Gain 105 - 107 Up to ~100 105 - 106

Excess noise ~1.2 3 − 4 ~1.1 – 1.2

Minimum detectablepower

Best BetterGood

Dynamic range Dependent on the voltage divider

Largest (high saturation level)

Dependent on thenumber of microcells

Temperatureeffects

Weak Strong Strong

SiPM and SPAD

Slide # 30

Additional attributes of SiPMs


• Operation immune to electric and magnetic fields

• Low bias voltage (10s of volts)

• No damage or lasting effects when exposed to full light

• Ability to make arrays and to mount on a circuit board

• Ruggedness

• Simple biasing circuit

Slide # 311/17/2019

Dark matter detection

SiPM and SPAD

Slide # 32

Background


• A galactic mass deduced from stellar kinematics is much larger than that implied by its luminous matter. The difference is known as dark matter.

• Dark matter interacts gravitationally but emits little or no light.

• The nature of dark matter is still not known.

• Among a number of possibilities, dark matter could be in the form of particles that can interact with “ordinary” matter.

• Active research exists in identifying the nature of dark matter.

Slide # 33

Detection concept for WIMPs


−Cathode

+Anode

Ground

Electric field

175-nm light from liquid Xenon scintillation

-95 °C

Xenon (L)

Xenon (G)

Photodetectors

PhotodetectorsDark matter particle (WIMP)

Electron

Light from ionized Xenon gas

Arb

.

S1

S2

Electron drift timeThese detect mostly S1

These detect mostly S2 Legend:

Slide # 34

Characteristics of received light


• Two pulses of light: S1 contains ~few tens of photons, while S2 ~few thousand

• Wavelength: UV and V

• Pulse duration: ~ns for S1 and ~μs for S2

Slide # 35

Photodetector requirements


• Photosensitivity in UV and V range

• High intrinsic gain (suppresses importance of electronic noise)

• High bandwidth (to avoid distortion of S1 pulse)

• Able to operate at low temperature (- 95 °C or 178 K)

Slide # 36

Product recommendation for liquid Xenon detection


VUV3 and VUV4

Array: Four 5.95×5.85 mm2 SiPMs

Each SiPM has 13,923 μ-cells, 50 μm pitch

Fill factor: 60%

From Bonesini et al. 2018

Slide # 37

Effect of temperature on the gain


From Bonesini et al. 2018

VUV4 • Breakdown voltage decreases with decreasing temperature.

• Gain depends on VBIAS - VBD

• If VBIAS – VBD is held constant, the gain is constant too.

Slide # 381/17/2019

Flow cytometry

SiPM and SPAD

Slide # 39

Flow cytometry: study of cells and micro-particles

1/17/2019

Interrogation oranalysis point

~100 μm~20 μm

Flow

SiPM and SPAD

• Used in medicine, biology, and engineering to study and sort cells and micro-particles

• Cells scatter interrogation light. The manner of scatter depends on the cell properties.

• The rate of interrogation is on the order of 1,000 cells per second or more.

Slide # 40

Flow cytometry basic concept

1/17/2019

FD

SCD

FSD

Laser 1

Las

er 2

Data collection & analysis

Beam mixer

DM

DM

Flow

Legend:FSD – forward-scatter detectorSCD – side-scatter detector

FD – fluorescence detectorDM – dichroic mirror

Fluorescence-taggedcell

SiPM and SPAD

Slide # 41

Flow cytometer: what is measured?

1/17/2019

time

FWHM

Area

Peak

Out

put v

olta

ge f

rom

pre

ampl

ifie

r

The front-end electronics can be set up to measure the peak value of the pulse, its FWHM, and/or area under the curve. These different measurements provide specific information about the cell.

Forward-scatter signal

Sid

e-s

catt

er

sig

nal

SiPM and SPAD

Slide # 42


1/17/2019

• Wavelength: can be selected depending on cell sizes and fluorescence

• Pulses: duration dependent on the sheath flow speed and cell size and is on the order of μs

• Number of photons per pulse varies from a few to thousands

• Rate of pulses is in kHz

SiPM and SPAD

Slide # 43

Photodetector requirement

1/17/2019

PD E

Photosensitivity/gain

Can we detect the red pulse?

PD E

saturation

Linearity & dynamic range

Is the output proportional to the input?

light input electricalsignal

SiPM and SPAD

Slide # 44


1/17/2019

PD E

Gain variation

PD E

increasing temperature

Temperature drift

How much excess noise is there? Does the gain depend on temperature?

SiPM and SPAD

Slide # 45


1/17/2019

PD E

Stability

PD E

Bandwidth

How stable are the photodetector’s characteristics such as gain?

Does the photodetector and detection electronics have enough bandwidth?

SiPM and SPAD

Slide # 46

Product recommendation for flow cytometry


Hamamatsu S14420 SiPM (MPPC) series

Slide # 471/17/2019

Bio- and chemiluminescenceluminometer

SiPM and SPAD

Slide # 48

Basic concept of a luminometer

1/17/2019

swab

tube

reagent

bacteria

photodetector

• Used to measure surface cleanliness

• The reagent reacts with the bacteria ATP, causing emission of light.

• The amount of light is proportional to the amount of ATP.

ATP – adenosine triphosphate

SiPM and SPAD

Legend:

Slide # 49

Characteristics of the received light


1. Wavelength in the 500 nm – 550 nm range

2. Diffuse (diffuse light cannot be focused)

3. Weak and slowly varying

diffuse light in

diffuselight out

lens

Inte

nsit

y

time~ 15 − 20 s

Slide # 50



1. Large active area

4. Low dark current

2. Photosensitivity in 500 – 550 nm range

3. Gain

5. Small detection bandwidth (limited by the amplifier)

frequency

Pow

er s

pect

rum

white noise spectrum

B1

B2

Wider bandwidth reduces S/N

Signal ~ A Noise ~ √A so S/N ~ √A

Slide # 51

Product recommendation for luminescence



Slide # 521/17/2019

Radiation monitoring

SiPM and SPAD

Slide # 53

Radiation monitoring basic concept


Scintillator Photodetector

Ionizing radiation time

E

trigger

Detection of radiation such as α, β, γ, and others. Applications in, for example, environmental monitoring, radiation safety, or security.

Output pulses

Slide # 54



• Pulses

• Number of photons per pulse depends on energy of the ionizing radiation and type of scintillator

• Duration of the pulse depends on the size and type of the scintillator (decay time constants range from ns to μs)

• Frequency of pulses depends on the rate of incoming radiation

Slide # 55



• High intrinsic gain

• Ability to couple to a scintillator

• Suitable for portable hand-held devices

• Large active area

• High photon detection efficiency

Slide # 56

Product recommendation for radiation detection


S14160 series

Slide # 571/17/2019

Time-of-flight LiDAR

SiPM and SPAD

Slide # 58

Time-of-flight (ToF) automotive LiDAR


• Automotive LiDAR is likely needed on a self-driving car to provide high-resolution 3D imaging of its surroundings.

• There is a great interest in developing self-driving cars.

• Photodetection and beam-steering are two most outstanding challenges in the development of an automotive LiDAR.

Slide # 59

Time-of-flight (ToF) LiDAR

1/17/2019

start pulse

stop pulse

laser

target

photodetector

timer

beam steeringsystem

Distance R

Measure time of flight Δt R = cΔt/2

λ = 905 nm or 1550 nm

SiPM and SPAD

Slide # 60

Characteristics of the received light

1/17/2019

Wavelength – 905 nm or 1550 nm

Pulses

Repetition period~μs

Duration~few ns

Peak power – few to 100’s of nW

SiPM and SPAD

Slide # 61


1/17/2019

• High quantum efficiency at 905 nm and/or 1550 nm (affects detection range)

• High detector (intrinsic) gain (reduces importance of electronic noise)

• Small excess noise (affects timing error)

• Small time jitter (affects distance error)

• High dynamic range

SiPM and SPAD

Slide # 621/17/2019

time

arb.

trig. level

Different trigger times: time walk effect

time

Histogram of responsetimes

Num

ber

FWHM

time

trig. leveljitter causes timing errors

SiPM and SPAD

Importance of excess noise Importance of photodetector jitter

Slide # 63

Importance of dynamic range

1/17/2019

arb.

time

saturation

trigger

dark currentand

background

• If fixed trigger is used, the changing background will affect timing.

• If constant fraction trigger is used, saturation will affect timing.

SiPM and SPAD

Slide # 64

Product recommendation for ToF LiDAR



Slide # 651/17/2019

Flash LiDAR

SiPM and SPAD

Slide # 66

Flash LiDAR

1/17/2019

projector

to the targetθ

The projector illuminates the scene with multiple divergent pulses of short duration (few ns).

SiPM and SPAD

Slide # 67

Flash LiDAR

1/17/2019

θ from target

FOV matched to theillumination FOV

2D array of detectors

timing circuit (all elements in parallel)

The returned light is imaged on an array of sensors. Each pixel measures distance to the imaged element of the scene.

SiPM and SPAD

Slide # 68

Flash LiDAR

1/17/2019

SPAD array

Repetitionperiod

timeN

o.2R/c

Histogram of trigger times

A histogram like the one above must be obtained for each pixel.

SiPM and SPAD

SPAD array by Hamamatsu is being developed. More information will be released at the Photonics West 2019 meeting.

Slide # 69

Summary and conclusions


Dark matterdetection ToF LiDAR

Flow cytometry

Radiation detection

ATP luminometer

Slide # 70

Summary and conclusions


• SiPMs as a family have a spectral response in the 120 nm – 1000 nm range.

• SiPMs enjoy an ever increasing adoption as the detector of choice in a wide range of applications.

• SiPM has an intrinsic gain comparable to that of a PMT, and on the order of 106.

• SPAD arrays open the possibility of single-photon imaging and may resolve engineering challenges in designing automotive LiDAR.

Slide # 71

Upcoming Hamamatsu Promotional Activities:


SPIE Photonics West 2019 (San Francisco), Wednesday, February 6, 2019 (8 hours)Mr. Koei Yamamoto (Director of Solid State and Laser Division from HQ Japan) is presenting two key topics highlighted in red:

• Part 1 (8:10 AM – 10:00 AM) – “Introduction to Photodetectors” (Slawomir Piatek)• Part 2 (10:15 AM − 11:45 AM) – “Evolution of Geiger Mode APD Technologies –

SiPM & SPAD” (Mr. Koei Yamamoto)• Part 3A (1:00 PM – 2:15 PM) – “Spectroscopy and Spectrometer Concepts” (Slawomir

Piatek)• Part 3B (2:15 PM – 3:00 PM) – “Spectroscopy and Spectrometer – What’s Next” (John

Gilmore)• Part 4A (3:15 PM – 4:00 PM) – “Automotive LiDAR: Design Concepts and

Challenges” (Jake Li)• Part 4B (4:00 PM – 5:00 PM) – “Photonics Technology Improvements that Drive

the Future of LiDAR Designs” (Mr. Koei Yamamoto)

Slide # 72Slide # 72

Microscopy Images

1/17/2019

Thank you for listening!

Contact: Slawomir [email protected]

SiPM and SPAD

For more info, see our past SiPM webinars linked below.

SiPM: Operation, performance, and possible applicationshttps://www.youtube.com/watch?v=HHS1qYfMDfk&t=430s

Low light detection: PMT vs. SiPMhttps://www.youtube.com/watch?v=I5dUB6LT4T4&t=2s

Documents

SPAD SIPM Final Presentation rr - Hamamatsu …...6OLGH 2XWOLQH 6L30 DQG 63$' ,QWURGXFWLRQ WR 31 MXQFWLRQ GHYLFHV )XQGDPHQWDOV RI VLQJOH SKRWRQ DYDODQFKH SKRWRGLRGH 63$' )XQGDPHQWDOV