National Research Nuclear University «MEPhI» Physics of SiPMs Dr. Elena Popova National Research Nuclear University «MEPhI» (elenap73@mail.ru) ICASIPM– the International Conference on the Advancement of Silicon Photomultipliers June 11 2018, Schwetzingen, Germany

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 11 2018

Elena Popova, MEPhI ICASIPM, June 11 2018

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 11 2018

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 11 2018

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 11 2018

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: 10.1081/E-EOE 120009727 Elena Popova, MEPhI ICASIPM, June 11 2018

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 3 - 11, 2007, Mérida, Yucatán, Mexico Elena Popova, MEPhI ICASIPM, June 11 2018

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 11 2018

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 #1702831. Priority time: 11.09.1989 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 2018

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: 10.1117/12.206900;https://doi.org/10.1117/12.206900 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 11 2018

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: 10.1117/12.206900;https://doi.org/10.1117/12.206900 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 11 2018

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: 10.1117/12.206900;https://doi.org/10.1117/12.206900 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 11 2018

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: 10.1117/12.206900;https://doi.org/10.1117/12.206900 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) http://www.amplificationtechnologies.com/index.html Elena Popova, MEPhI ICASIPM, June 11 2018

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 11 2018

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, 347-352 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 11 2018

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. 187-192. 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, 2018 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 11 2018

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. 717-728. Samples produced by MEPhI/PULSAR team Silicon Photomultiplier (SiPM)– the name given by prof. Boris Dolgoshein PDE (550-660nm)≈15% Elena Popova, MEPhI ICASIPM, June 11 2018

Multiphoton Timing with SiPM NIM A442 (2000), pp. 187-192 Laser (660nm) signal width =700ps 700 Advanced Technology and Particle Physics: pp. 717-728. Laser (670nm) signal width =40ps 90 ps For discussions of SiPM timing properties Wednesday, June 13, 2018 Timing Properties (FAST Action WG3 meeting) - Stefan Gundacker Elena Popova, MEPhI ICASIPM, June 11 2018

The end of pre-SiPM Physics history Modern history of SiPM: from 2000 until the time being Modern questions are subjects of the our conference! Elena Popova, MEPhI ICASIPM, June 11 2018

Amplitude (exp) 1 2 3 Charge (exp) Elena Popova, MEPhI 1 2 3 Charge (exp) Elena Popova, MEPhI ICASIPM, June 11 2018

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 11 2018

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 11 2018

Modern trend: analog SiPM inside of Digital one Elena Popova, MEPhI ICASIPM, June 11 2018

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 11 2018