๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved. 1
MPPC & SPAD
Future of Photon Counting Detectors
Slawomir Piatek
New Jersey Institute of Technology &
Hamamatsu Photonics, Bridgewater, NJ, USA
10.1. 2019
2๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
โ Introduction
โ Single-Photon Avalanche Photodiode (SPAD)
โ Silicon Photomultiplier (SiPM)
โ Concluding remarks
Index
3๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Introduction
4๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Terminology
PD โ Photodiode
APD โ Avalanche photodiode
SPAD โ Single-photon avalanche photodiode
SiPM โ Silicon photomultiplier
MPPC โ Multi-pixel photon counter; another name for SiPM
PMT โ Photomultiplier tube
The same
SPPC โ Single-pixel photon counter; another name for SPAD The same
5๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Generic PN junction: modes of operation
๐ผ
๐
๐๐ต๐ท
linear mode APD
operates in this region
PD operates in
this region
โโ
SPAD and SiPM
operate in this region
๐
๐ผ
Ge
ige
r re
gio
n
6๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
PN junction devices
โ๐
๐
๐
๐๐ต๐ผ๐ด๐
PD
โ๐
๐
APD
โ๐
๐
SPAD
1 ๐พ โ 1 pair 1๐พ โ ~100 pairs 1๐พ โ โ pairs
๐๐ต๐ท
๐
๐ผ ๐๐ต๐ท
๐
๐ผ๐๐ต๐ท
๐
๐ผ
๐๐ต๐ผ๐ด๐ ๐๐ต๐ผ๐ด๐
๐ ๐
7๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Attributes of a photodiode
1. Detector of choice for sufficiently high input light level
2. Wide spectral coverage (from UV to IR) for a family of photodiodes
3. Inexpensive and easy to use
4. Low intrinsic noise
5. Can be used in arrays and available in modules
Si PDs InGaAS PDs PD arrays with
amplifier
PD module
8๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Attributes of an avalanche photodiode (linear mode)
1. Detector of choice for light levels too high for a PMT/SiPM but too low for a photodiode
2. Intrinsic gain up to ~100
3. Wide spectral coverage 200 ๐๐ โ 1700 ๐๐ for a family of avalanche photodiodes
4. Can be used in arrays
5. Available as part of a module
Si APDs InGaAs APDs Si APD array APD module
9๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Single-Photon Avalanche Photodiode (SPAD)
10๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Operation of a SPAD
SPAD
photon
time
cu
rre
nt
avalanche starts here
Once triggered, the avalanche
is perpetual; however, the SPAD
is no longer sensitive to light.
Without quenching, SPAD operates as a light switch.
๐๐ต๐ผ๐ด๐ > ๐๐ต๐ท
11๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Operation of a SPAD (passive quenching)
SPAD
๐๐ต๐ท
steady state
transient
quench
recharge
๐ ๐ must be large enough to ensure quenching.
quasi-stable โreadyโ
state
photon
๐ ๐
๐๐ต๐ผ๐ด๐
๐ ๐
๐ผ๐๐๐ด๐ท
๐ ๐ โซ ๐ ๐
๐๐๐๐ด๐ท๐๐ต๐ผ๐ด๐
๐๐ต๐ผ๐ด๐๐ ๐
โ๐ = ๐๐ต๐ผ๐ด๐ โ ๐๐ต๐ท (overvoltage)
12๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Operation of a SPAD (passive quenching)
๐
VBD
SPAD
time
๐ผ
Observed output current pulse
quenching occurs
around here
๐ผ๐๐๐ด๐ท
๐๐๐๐ด๐ท
ON
OFF
๐๐ต๐ผ๐ด๐๐๐ต๐ท
Rise time ~๐ ๐๐ถ๐ฝ few ns
Fall time ~๐ ๐๐ถ๐ฝ tens of ns๐ ๐~100๐ ฮฉ
๐๐ต๐ผ๐ด๐ > ๐๐ต๐ท
๐ ๐~100๐ ๐ฮฉ
๐ =๐๐๐๐ฅ๐ ๐๐ถ๐ฝ
๐=
๐๐ต๐ผ๐ด๐ โ ๐๐ต๐ท ๐ ๐๐ถ๐ฝ
๐ ๐ ๐ + ๐ ๐โ
๐๐ต๐ผ๐ด๐ โ ๐๐ต๐ท ๐ถ๐ฝ๐
=โ๐๐ถ๐ฝ๐
(gain)
๐๐ต๐ผ๐ด๐ โ ๐๐ต๐ท
๐ ๐ + ๐ ๐
~๐โ๐ก/๐ ๐๐ถ๐ฝ~ 1 โ ๐โ๐ก/๐ ๐๐ถ๐ฝ
๐ก๐ ๐ก๐๐๐ฅ
๐๐๐๐ฅ
๐ถ๐ฝ~100 fF
13๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Operation of a SPAD (passive quenching)
SPAD
photon
๐ ๐
๐๐ต๐ผ๐ด๐
๐ ๐
๐ ๐ โซ ๐ ๐
time
quench
๐~๐ ๐๐ถ๐ฝ (recovery characteristic time)
recovery
Voltage pulse on ๐ ๐ due to avalanche
๐๐
10๐ โ 100๐ of ๐๐
14๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Photon counting with SPAD
๐ ๐
๐๐ต๐ผ๐ด๐
๐ ๐
๐ฃ ๐ก
time
๐ฃ ๐ก
no light
time
๐ฃ ๐ก
yes light
dark counts๐ถ
15๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Photon counting with SPAD
๐ ๐
๐๐ต๐ผ๐ด๐
๐ ๐
๐ฃ ๐ก
time
๐ฃ ๐ก
Pulses with a duration
much shorter than the
recovery time.
๐
๐
16๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Photon counting with SPAD
๐ ๐
๐๐ต๐ผ๐ด๐
๐ ๐
๐ฃ ๐ก
time
๐ฃ ๐ก
Pulses with a duration
longer than the
recovery time.
๐
๐
๐
๐
17๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Photon counting with SPAD
๐ ๐
๐๐ต๐ผ๐ด๐
๐ ๐
๐ฃ ๐ก
time
๐ฃ ๐ก
DC
18๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Active quenching
Reference: โProgress in Quenching Circuits for Single Photon Avalanche Diodes,โ Gallivanoni, A., Rech, I., & Ghioni, M., IEEE Transactions
on Nuclear Science, Vol. 57, No. 6, December 2010
๐ ๐
๐๐ด < 0
Pulse
generator
โ
+๐๐กโ
time
time
Ca
tho
de
vo
lta
ge
Dio
de
cu
rre
nt
hold-off time
avalanche
starts here
Basic concept of active
quenching. quenching
occurs here
comparator
๐ ๐ โ current sensing resistor (small)
19๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Photon Detection Efficiency
Ph
oto
n d
ete
ction
effic
ien
cy,
๐
Wavelength, ๐
Photon detection efficiency is a probability that the incident photon is detected. It is a
function of wavelength and overvoltage.
๐ = ๐ ๐, ฮ๐
fixed ฮ๐
20๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Photon Detection Efficiency
Ph
oto
n d
ete
ction
effic
ien
cy,
๐
Overvoltage, โ๐ [๐]
For a given wavelength, photon detection efficiency increases with overvoltage.
fixed ๐
21๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Dark count rates
Da
rk c
ou
nt ra
te ๐/๐
Overvoltage, โ๐ [๐]
Da
rk c
ou
nt ra
te ๐/๐
Temperature โ
Dark count rate depends on temperature and overvoltage. Typical values at room temperature and
recommended overvoltage are 10๐ โ 100๐ ๐/๐ , depending on the device design.
fixed ฮ๐fixed ๐
22๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
After-pulsing
time
photonlight-sensitive light-sensitive
time
photonlight-sensitive light-sensitive
normal
with after-pulsing
full recovery
full recovery
SPAD
SPAD
23๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Product example by Hamamatsu (C14463-050GD)
Photon counting module with SPAD
(SPPC)
wavelength ๐๐
Ph
oto
n d
ete
ction
effic
ien
cy %
No. of incident photons ๐/๐ N
o. o
f d
ete
cte
d p
ho
ton
s ๐/๐
linearityPDE
24๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
SPAD Array
1
2
3
4
5
6
7
8
9
1 2 3
4 5 6
7 8 9
Each element of the array (pixel) has its own quenching circuitry (passive or active).
Outputs
25๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
SPAD Array; Crosstalk
1
2
3
4
5
6
7
8
9
1 2 3
4 5 6
7 8 9
Each element of the array (pixel) has its own quenching circuitry (passive or active).
26๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Product example by Hamamatsu (S15008-100NT-01)
27๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Product example by Hamamatsu (S15008-100NT-01)
28๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Comments on SPAD arrays
1. The array can be customized to specific userโs needs.
2. Hamamatsu is working on improving crosstalk.
3. Hamamatsu is working on higher resolution array (smaller pixels).
4. Hamamatsu is working on IR version of the array.
5. Hamamatsu will work with users on developing customized ASICs
6. Demos are available for evaluation.
29๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Importance of ASIC (example)
t = 0
time
timer
targetSPAD
laser
Puls
e e
mis
sio
n๐ก = ๐
ฮ๐ก =2๐
๐
Measuring distance with a SPAD
30๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Importance of ASIC (example)
time
๐ก = 0 ๐ก = ๐ฮ๐ก =
2๐
๐
Histogram of trigger times
1. Multiple pulse illumination provides distance information to the target. The information comes
from a histogram of trigger times.
2. An ASIC producing such histogram (per pixel) is part of the sensor.
31๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Silicon Photomultiplier (SiPM)
32๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Naming conventions
SiPM โ Silicon Photomultiplier
MPPC โ Multi-Pixel Photon Counter
SSPM โ Solid-State Photomultiplier
PMAD โ Multi-Pixel Avalanche Photodiode
G-APD โ Geiger Mode Avalanche Photodiode
MPGM APDs โ Multi-Pixel Geiger-Mode Avalanche Photodiodes
Most-commonly-used names
33๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Structure
SiPM is an array of microcells
=๐ด๐๐ท
p+
ฯ
n+
p+
oxide
Single microcell
electrical equivalent circuit
of a single microcell
Sid
e v
iew
Top v
iew
๐ ๐
Also known as multi-pixel photon counter (MPPC)
34๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Structure
...
Anode
Cathode
single microcell
APD
๐ ๐
All of the microcells are connected in parallel.
35๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Example of models
S13360-6050VE
surface mount, 6ร6 mm2,
14,555, 50ร50 ฮผm2
S13360-3050DG
metal can, TE
cooled, 3ร3 mm2,
3,600, 50ร50 ฮผm2
S13360-1325CS
ceramic, 1.3ร1.3 mm2,
2,668, 25ร25 ฮผm2
surface mount, 1.3ร1.3
mm2, 285, 75ร75 ฮผm2
S13360-1375PE
DG โ metal can
CS โ ceramic
PE โ surface mount
VE โ 4-side buttable (best for arrays)
36๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Operation
๐๐ต๐ผ๐ด๐ > ๐๐ต๐ท
๐ ๐
time
๐ฃ1 ๐ฃ2
โ๐
โ๐
๐1๐2
37๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Anatomy of a pulse
time [ns]
Am
plit
ude [m
V]
Fast component
Slow component
โ The ๐ ๐ถ time constant of the slow component depends on microcell
size (all else being equal)
โ The recovery time ๐ก๐ โ 5 ร the ๐ ๐ถ time constant
โ ๐ก๐ is on the order of 10s to 100s of ns but in practical situations it is
also a function of the detection bandwidth
38๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Crosstalk
Primary discharge can trigger a secondary
discharge in neighboring microcells. This is
crosstalk.
time
Arb
.
2 p.e. crosstalk event
Crosstalk probability depends on overvoltage.
39๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Temperature compensation
๐พ
๐ด
Temperature sensor
Control unit
Variable power supply
Example of SiPM (MPPC) module
with temperature compensation
๐๐ต๐ท ๐ = ๐๐ต๐ท ๐0 + ๐ฝ ๐ โ ๐0(breakdown voltage depends
on temperature)
The role of the control unit is to adjust ๐๐ต๐ผ๐ด๐ so that the overvoltage ฮ๐ remains
constant (and thus gain) as temperature changes.
40๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Product example by Hamamatsu (S13360, 50 ๐๐ pitch)
Ga
in
Cro
ssta
lk p
rob
ab
ility,
ph
oto
n d
ete
ctio
n e
fficie
ncy %
Overvoltage ๐
Ph
oto
n d
ete
ction
effic
ien
cy %
Wavelength ๐๐
41๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Linearity and dynamic range (๐ฟ illumination)
๐๐ โAverage number of fired ฮผ-cells
In the limit of ๐ฟ โillumination, dynamic range and linearity depend on the number of microcells.
๐๐ก โ Number of microcells
๐๐พ โ Number of photons in a pulse
Ideally linear
From Grodzicka et al. 2015
Hamamatsu S10362-33-25C
& S10985-025C
solid lines fits to
the equation
Number of potentially detectable photons
๐๐
๐๐ = ๐๐ก 1 โ ๐โ๐๐พโ๐๐ท๐ธ/๐๐ก
42๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Linearity and dynamic range (finite-pulse illumination)
For a given number of photons in a pulse, the number of effective fired microcells increases
with the pulse duration.
๐๐ โ Pulse duration
๐ก๐ โ Recovery time
Number of potentially detectable photons
3,600 microcells
3 ร 3 ๐๐2
From Grodzicka et al. 2015
๐๐
๐๐ = ๐๐ก๐๐๐ก๐
1 โ ๐๐ฅ๐โ๐๐พ โ ๐๐ท๐ธ
๐๐๐ก๐
๐๐ก
43๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Linearity and dynamic range (DC)
Incident light level ๐
Outp
ut
curr
ent ๐ด For some SiPMs Hamamatsu provides a linearity plot for DC
illumination. This plot can be transcribed from ๐ = 850 ๐๐ to
any other wavelength.
44๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Modes of operation
time
incid
ent lig
ht le
vel
(photon counting)
(analog)
45๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Analog
๐๐โ = ๐๐ 1 + ๐๐๐ก๐๐ท๐ธ โ ๐ โ ๐
โ๐
โ
+
๐ฃ๐
๐ ๐
๐ถ๐น
๐๐โ
๐๐ต
๐ ๐
๐=
๐๐โ๐ ๐
๐๐๐2 ๐ ๐
2 + ๐๐ท๐2 ๐ ๐
2 +4๐๐ฮ๐๐ ๐
๐ ๐2
๐๐๐2 = 2๐๐๐โ๐๐นฮ๐
๐๐ท๐2 = 2๐๐๐ท๐๐นฮ๐
(signal photon shot noise)
(dark current shot noise)
๐๐ฝ2 =
4๐๐ฮ๐
๐ ๐(Johnson noise of the feedback resistor)
46๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Photon counting
LLD
ULD
Time
Time
preamplifierSiPM amplifier discriminator pulse shaper counter
1,2, โฆ
47๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Photon counting
๐
๐=
๐๐ ๐๐๐ฅ๐
๐๐ + 2 ๐๐ต + ๐๐ท
๐๐๐ฅ๐ โ measurement time
๐๐ = ๐๐ก๐๐ก โ ๐๐ต + ๐๐ท
๐๐ก๐๐ก โ number of counts per unit time due to โscienceโ light, background light, and dark counts
๐๐ต โ number of counts per unit time due to background light
๐๐ท โ number of counts per unit time due to dark current
All rates are measured with the same exposure time ๐๐๐ฅ๐
48๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Modes of operation
Outp
ut c
urre
nt ๐ด
Num
ber
of
dete
cte
d p
hoto
ns ๐/๐
Number of incident photons ๐/๐
Input light power ๐
Minimum detection limit (MDL) can be lowered by cooling and limiting the detection bandwidth.
3ร3 mm2, 50 ฮผm
49๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
SiPM imaging array, product example by Hamamatsu
S15013-0125NP-01
2D MPPC photon counting image sensor
This array can be used for imaging and for ToF distance measurement (e.g., in flash LiDAR).
50๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
SiPM imaging array, product example by Hamamatsu
51๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
SiPM imaging array, product example by Hamamatsu
Demo units, together with evaluation and interface boards, are available to potential users.
52๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Future Applications for SPAD Arrays
Quantum Technology โ Quantum Key Distribution
Brain Activity Monitoring
Solid State Flash LiDAR
53๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Closing remarks
1. Photon counting can be a preferred detection technique when the incident light level is low.
2. SPAD and SiPM are well-suited for photon counting.
3. SPAD and SiPM image sensors are being developed.
4. Research and development continues to extend the detection into the IR regime.
5. Integration of ASICs with the SPAD or SiPM imagers is the most cost-effective approach.
Hamamatsu provides support and will work with individual customers to provide solutions.
54๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Join Us for 10 Weeks of FREE Photonics Webinars (17 Topics)
Week # Weekly Topics # of Talks Talk #1 Date Talk #2 Date
1 Introduction to Photodetectors 2 26-May-20 28-May-20
2 Emerging Applications - LiDAR & Flow Cytometry 2 2-Jun-20 4-Jun-20
3 Understanding Spectrometer 2 9-Jun-20 11-Jun-20
1 Week Break
4 Specialty Products โ Introduction to Light Sources & X-Ray 2 23-Jun-20 25-Jun-20
5 Introduction to Image Sensors 2 30-Jun-20 02-Jul-20
1 Week Break
6 Specialty Products โ Laser Driven Light Sources 2 14-Jul-20 16-Jul-20
7 Image Sensor Circuits and Scientific Camera 2 21-Jul-20 23-Jul-20
8 Mid-Infrared (MIR) Technologies & Applications 2 28-Jul-20 30-Jul-20
1 Week Break
9 Photon Counting Detectors โ SiPM and SPAD 1 11-Aug-20
10 Using SNR Simulation to Select a Photodetector 1 18-Aug-20
To register for other webinars or hear previous webinar recordings, please visit link below:
https://www.hamamatsu.com/us/en/news/event/2020/20200526220000.html
55๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved.
Thank you
Thank you for listening.
Contact information:
๐ซ Hamamatsu Photonics K.K. and its affiliates. All Rights Reserved. 56