1. National Research Nuclear University «MEPhI»
Physics of SiPMs
Dr. Elena Popova
National Research Nuclear University «MEPhI»
ICASIPM– the International Conference on the Advancement of Silicon Photomultipliers
June , Schwetzingen, Germany

2. ICASIPM – the first International Conference on the Advancement of Silicon Photomultipliers (SiPM)
The one of the most important goals of the conference is standartization of
SiPM characterization and we have a lot of topical sessions devoted to the
different SiPM parameters.
However the first task of the conference has to be a development of a definition
what is the SiPM (analog SiPM) ?
SiPM is a novel type of photon number resolving limited Geiger-mode solid state photodetectors
It means that we have to develop special kind of standards for SiPM
characterization (maybe not existing now)
According to the Russian classification system –
SiPM is a IC (microcircuit, integrated circuit)
In principle it is the same as for Digital SiPM
Elena Popova, MEPhI
ICASIPM, June

3. Elena Popova, MEPhI
ICASIPM, June

4. At present all known to me SiPMs are based on jointed together p-n-junctions which operate in limited (self-quenching) Geiger mode
P-n-junction is a SiPM’s cell.
If p-n-junction is located stand-alone, outside of the SiPM (e.g. as a test structure) –
It can be considered as a SPAD (Single Photon Avalanche Detector)
One important note – SiPM cell is equal to SPAD if SPAD has local (situated in a close vicinity with p-n-junction, not as an external circuit elements) passive/active quenching.
Many SPADs jointed together
and having common readout
is a SiPM
SPAD
2 SiPM cells
SPAD – passive and active circuit – CMOS technology
SiPM cell – passive circuit – custom technology
Elena Popova, MEPhI
ICASIPM, June

5. Silicon Photomultiplier (SiPM) or Solid State Photomultiplier (SSPM)
Amplitude (charge) spectrum
R 50 h
pixel
U 60V
substrate
Scope signal
0 pe
1 pe
2 pe
3 pe
4 pe
Common features of SiPMs (SSPMs)
Multi-cell device with common readout
Each cell – p-n-junction in self-quenching Geiger mode
All cells are equal
cells are independent from each other
Signal – is analog sum of all fired cells
cell signal – well defined even if it hardly visible due to low gain ( 0 or 1)
SiPM is an analog device
Elena Popova, MEPhI
ICASIPM, June

6. Here is a little bit additional History of SiPM Physics
A Brief History of SiPMs and SiPM Physics have been presented already in the nice talk of
Zair Sadygov
Here is a little bit additional History of SiPM Physics
At the beginning, pre-SiPM devices operated without p-n-junction(s)…
Elena Popova, MEPhI
ICASIPM, June

7. Lebedev Physical Institute Academy of Science, Moscow
Mid -1970s USSR
Lebedev Physical Institute Academy of Science, Moscow
MIS (metal-insulator-silicon) structures differ from the traditional avalanche structures by the presence of a wideband, high-resistance buffer layer preventing output of the charge carriers from multiplication layer.
…In the mid-1970s, a concept was developed regarding an Avalanche process with the Negative Feedback (ANF) appearing because of the accumulation of the charge carriers produced by the avalanche at the multiplication region boundary… [Kravchenko, A.B.; Plotnikov, A.F.; Shubin, V.E. Feasibility of construction of a pulsed avalanche photodetector based on MIS structure with stable internal amplification. J. Quantum Electron. 1978, 8, 1086, 1399]
SiO2 Me
p-Si +U
But developed theory was based on classical avalanche process approach (no single carriers but currents densities instead, no probabilistic theory)
-> No single photon sensitivity
Avalanche Photodetectors. Vitaly E. Shubin, Dmitry A. Shushakov Encyclopedia of Optical Engineering
DOI: /E-EOE
Elena Popova, MEPhI
ICASIPM, June

8. Moscow electric lamp factory (MELZ) V.Golovin, N.Yusipov
1988 USSR
Moscow electric lamp factory (MELZ) V.Golovin, N.Yusipov
Institute Nuclear Research (INR) Z. Sadygov, A. Gasanov, et al.)
Publication on the plane MRS APD: A.Gasanov, V.Golovin, Z.Sadygov, N.Yusipov. –Technical Physics Letters (in Russian), v.14, No.8, p.706, (1988).
Novel Micro-pixel Avalanche Photo Diodes and their
Novel Micro-pixel Avalanche Photo Diodes and their
Novel Micro-pixel Avalanche Photo Diodes and their
Possible Application in Cos-
Possible Application in Cos-
Possible Application in Cos-
The same classical avalanche process approach (definetly connections between Lebedev group and authors) ,
But more stable and promising operation of the MRS structures
mic Ray/Astrophysical Researches
mic Ray/Astrophysical Researches
mic Ray/Astrophysical Researches
Novel Micro-pixel Avalanche Photo Diodes and their Possible Application in Cosmic Ray/Astrophysical Researches Zheleznykh, I.M.; Sadygov, Z.Ya.; Khrenov, B.A.; Tkatchev, L.G.; Zerrouk, F. Publication: Proceedings of the 30th International Cosmic Ray Conference. July , 2007, Mérida, Yucatán, Mexico
Elena Popova, MEPhI
ICASIPM, June

9. Photocurrent multiplication vs light pulse intensity
1988 USSR
Dark IV curves
Photocurrent multiplication
vs light pulse intensity
Points – experiment, solid lines -simulation
Publication on the plane MRS APD: A.Gasanov, V.Golovin, Z.Sadygov, N.Yusipov. –Technical Physics Letters (in Russian), v.14, No.8, p.706, (1988).
Understandable theory of MRS structure operation didn’t exist yet
Elena Popova, MEPhI
ICASIPM, June

10. Understandable theory of MRS structure operation didn’t exist yet
The first micro-pixel avalanche photodiode was born. P-n junction are here now!
1989 USSR
A.Gasanov, V.Golovin, Z.Sadygov and N.Yusipov. Russian patent # Priority time:
MRS structure with n+ cells
The first publication about MRS structure with n+ cells:
A. Gasanov, V. Golovin, Z. Sadygov, N. Yusipov. –Technical Physics Letters (in Russian), v.16, No.1, p.14, (1990)
Reference MRS structure without n+ cells
Understandable theory of MRS structure operation didn’t exist yet
Elena Popova, MEPhI
ICASIPM, June

11. New solid state photomultiplier,
1995 Russia
New solid state photomultiplier,
D. Shushakov, V. Shubin, Lebedev Institute Academy of Science
Proc. SPIE 2397, Optoelectronic Integrated Circuit Materials, Physics, and Devices, (24 April 1995); doi: / ;
Plane SiC-Si ANF heterostructure (MRS without n+ cells)
New theory was born - new physics of a Single-Carrier-initiated Avalanche
Negative Feedback process (SC ANF process)
…The main difference between such a structure and a conventional avalanche photodiode (APD) is nonstationarity of the electrical field strength in an avalanche region caused by the local area (10 m2) feedback…
…It is shown that when the non-stationarity is manifested at amplification of a single photocarrier, it changes radically the main characteristics of the avalanche process…
No any more current densities (conventional avalanche process) – single carrier Monte-Carlo simulation
Operational Voltage is above breakdown – overvoltage – limited Geiger discharge due to the local feedback
Elena Popova, MEPhI
ICASIPM, June

12. Experimental waveform With Charge sensitive preamp
New solid state photomultiplier,
D. Shushakov, V. Shubin, Lebedev Institute Academy of Science
Proc. SPIE 2397, Optoelectronic Integrated Circuit Materials, Physics, and Devices, (24 April 1995); doi: / ;
1995 Russia
The gain G of SC ANF process depends on the overvoltage value and the local negative feedback coefficient (C)
G = C*ΔU/e, where C - the capacity of insulator layer, ΔU=U-Ubr
Experimental waveform
With Charge sensitive preamp
Simulated Gain distribution for single injected carrier
U1>U2
Experimental distribution of gain G
Pedestal
1 phe
Elena Popova, MEPhI
ICASIPM, June

13. New solid state photomultiplier, 1995 Russia
D. Shushakov, V. Shubin, Lebedev Institute Academy of Science
Proc. SPIE 2397, Optoelectronic Integrated Circuit Materials, Physics, and Devices, (24 April 1995); doi: / ;
1995 Russia
Calculated probability Pr that a single electron will give a detectable pulse when the average Gain is G and discriminator is set at 1000 electrons
Attempt to calculate Photon Detection Efficiency (PDE) of a single initial carrier
When several photons are falling on to the structure simultaneously (but not at the same place), they are amplified independently due to the negative feedback locality, and produce a summarized output signal
Elena Popova, MEPhI
ICASIPM, June

14. New solid state photomultiplier, 1995 Russia
D. Shushakov, V. Shubin, Lebedev Institute Academy of Science
Proc. SPIE 2397, Optoelectronic Integrated Circuit Materials, Physics, and Devices, (24 April 1995); doi: / ;
1995 Russia
Summary
A concept of a novel solid state photosensor with an internal amplification based on the avalanche process with the negative feedback was considered
Single initial carrier – potential above breakdown – strong impact ionization –
very fast local charge accumulation – discharge filament switched off
Solid state analog of a vacuum-tube photomultiplier –
high gain,
low noise
small response time.
But higher quantum efficiency!
The avalanche devices based on different kinds of semiconductor materials may be designed.
This would allow one to manufacture avalanche photosensors for different urgent spectral ranges.
Amplification Technology , USA (DAPD)
Elena Popova, MEPhI
ICASIPM, June

15. Intrinsic gain (amplification
1997 Russia
New results on MRS APDs
ITEP team
A.V. Akindinov, A.N. Martemianov, P.A. Polozov, V.M. Golovin, E.A. Grigoriev, Nucl. Instr. and Meth. A 387 (1997) 231
In 1997 year the a single photoelectron resolution with this MRS APD with n+ dots produced by MELZ (V.Golovin) was firstly observed.
This confirms the suggestion [*] that this device works in limited Geiger mode.
* E. Grigoriev, F. Lemeilleur and G. Stefanini, communications
at special seminars at CERN (ECP), INFN (Piss), CPPM (Marseille) and CNRS (Strasbourg), March-April 1993, unpublished.
Intrinsic gain (amplification
coefficient for a single primary charge) can be
determined from the interval between two adjacent peaks.
???Light detection efficiency depends in a complicated way on both the wavelength and reverse bias voltage.
Elena Popova, MEPhI
ICASIPM, June

16. Photodiode signal distributions for low intensity light pulses
1998 Russia
Limited Geiger-mode silicon photodiode with very high gain. MEPHI team G.Bondarenko B.Dolgoshein V.Golovin A.Ilyin R.Klanner E.Popova Nucl. Phys. B – Proc. Suppl., V. 61, Issue 3, February 1998,
Photodiode signal distributions for low intensity light pulses
MRS APD with n+ dots produced by MELZ (V.Golovin)
PDE(670 nm)≈1% calculated on the basis of
<N>=-lnP(0), the average number of cells fired <N> is calculated using the Poisson distribution formula, where P(0) is the probability to have no fired cells
Tuesday, June 12, 2018 Photon Detection Efficiency - Nepomuk Otte
Finite number of cells:
Thursday, June 14, 2018 Nonlinearity and Saturation - Sergey Vinogradov
Elena Popova, MEPhI
ICASIPM, June

17. Limited Geiger-mode microcell silicon photodiode: new results.
MEPHI team
G.Bondarenko, P.Buzhan, B.Dolgoshein, V.Golovin, E.Guschin, A.Ilyin, V.Kaplin, A.Karakash, R.Klanner, V.Pokachalov, E.Popova, K.Smirnov.
Nucl.Instr.Meth.Phys.Res. A442 (2000), pp
2000 Russia
New samples of MRS APD with n+ dots produced by MELZ (V.Golovin)
PDE (570 nm)≈8%
…Unfortunately the simple way to increase PDE just increasing the n+-pins density does not help, because the higher n+-pins density
leads to strong coupling between neighbour pixels, deteriorates the pixels independency and limited Geiger-mode performance…
Crosstalk was recognized as an important problem!
First attempt of the crosstalk suppression
Wednesday, June 13, Nuisance Parameters - Alberto Gola
Technology which allows to obtain high PDE and
low crosstalk has to be developed
V.Golovin – CPTA (Russia) - Photonique SA (Swiss)
Elena Popova, MEPhI
ICASIPM, June

18. Samples produced by MEPhI/PULSAR team
2000 Russia
The advanced study of silicon photomultiplier MEPHI/PULSAR team P. Buzhan, B. Dolgoshein, A. Ilyin, V. Kantserov, V. Kaplin, A. Karakash, A. Pleshko, E. Popova, S. Smirnov, Yu. Volkov, L. Filatov, S. Klemin, and F. Kayumov (2002) Advanced Technology and Particle Physics: pp
Samples produced by MEPhI/PULSAR team
Silicon Photomultiplier (SiPM)– the name given by prof. Boris Dolgoshein
PDE ( nm)≈15%
Elena Popova, MEPhI
ICASIPM, June

19. Multiphoton Timing with SiPM
NIM A442 (2000), pp
Laser (660nm) signal width =700ps
700
Advanced Technology and Particle Physics: pp
Laser (670nm) signal width =40ps
90 ps
For discussions of SiPM timing properties
Wednesday, June 13, Timing Properties (FAST Action WG3 meeting) - Stefan Gundacker
Elena Popova, MEPhI
ICASIPM, June

20. The end of pre-SiPM Physics history
Modern history of SiPM: from until the time being
Modern questions are subjects of the our conference!
Elena Popova, MEPhI
ICASIPM, June

21. Amplitude (exp) 1 2 3 Charge (exp) Elena Popova, MEPhI
1 2 3
Charge (exp)
Elena Popova, MEPhI
ICASIPM, June

22. Signals from stand alone cell
LGP signal distributions for low intensity light pulses
Signals from stand alone cell
Fixed overvoltage U=1.65V, different light intensity
Amplitude (exp)
1 2 3
If we are working with amplitude (not with charge) we can distinguish number of initial phes even inside of single SiPM cell!
Elena Popova, MEPhI
ICASIPM, June

23. Signals from stand alone cell
Plane SiC-Si ANF heterostructure (without n+ cells)
Signals from stand alone cell
Fixed overvoltage U=1.65V, different light intensity
Low intensity light pulse
Waveform with charge sensitive preamp
Amplitude (exp)
1 2 3
Future trend? No dead area – the highest PDE
But gain has to be very low (crosstalk supression) – embedded on the same chip amplifiers are required
Elena Popova, MEPhI
ICASIPM, June

24. Modern trend: analog SiPM inside of Digital one
Elena Popova, MEPhI
ICASIPM, June

25. ICASIPM – first international SiPM conference devoted to the SiPM standartization
SiPM definition???
SiPM is a novel type of photon number resolving limited Geiger-mode solid state photodetector
Multi-cell device with common readout in such a way that output signal is an analog sum of all fired cells
Each cell – operates with local Negative Feedback provided limited Geiger mode regime
All cells are equal
Cells are independent from each other
Elena Popova, MEPhI
ICASIPM, June