RD50 Collaboration Overview: Development of New Radiation Hard Detectors

Transcription

1 RD50 Collaboration Overview: Development of New Radiation Hard Detectors FRONTIER DETECTORS FOR FRONTIER PHYSICS 13th Pisa Meeting on Advanced Detectors Susanne Kuehn, Albert-Ludwigs-University Freiburg On behalf of the RD50 Collaboration

2 Outline Introduction Results from Research Fields of the RD50 Collaboration aiming for radiation hard detectors for future collider experiments Defect Characterization Detector Characterization and Full Detector Systems Development of New Structures Summary Only a selection on interesting topics, the full variety of RD50 can be found on: 2

3 Structure and Research Fields of RD50 Co-Spokespersons Gianluigi Casse and Michael Moll (Liverpool University) (CERN PH-DT) Defect / Material Characterization Detector Characterization New Structures Ioana Pintilie Eckhart Fretwurst (NIMP Bucharest) (Hamburg University) Giulio Pellegrini (CNM Barcelona) Characterization of test structures (IV, CV, CCE, TCT) Development and testing of defect engineered silicon devices EPI, MCZ and other materials NIEL (experimental) Device modeling Operational conditions Common irradiations Devices Simulations (V. Eremin) Wafer procurement (M.Moll) 3D detectors Thin detectors Cost effective solutions Detectors with internal gain (avalanche detectors) Slim edges Other new structures Characterization of microscopic properties of standard-, defect engineered and new materials pre- and postirradiation DLTS, TSC, SIMS, SR, NIEL (calculations) WODEAN: Workshop on Defect Analysis in Silicon Detectors (G.Lindstroem & M.Bruzzi) 3D (R.Bates) LGAD (V. Greco) Slim Edges (Vitaliy Fadeyev) Full Detector Systems Gregor Kramberger (Ljubljana University) LHC-like tests Links to HEP Links electronics R&D Low rho strips Sensor readout (Alibava) Comparison: - pad-mini-full detectors - different producers Radiation Damage in HEP detectors Test beams (M. Bomben & G.Casse) Collaboration Board Chair & Deputy: G.Kramberger (Ljubljana) & J.Vaitkus (Vilnius), Conference committee: U.Parzefall (Freiburg) CERN contact: M.Moll (PH-DT), Secretary: V.Wedlake (PH-DT), Budget holder & GLIMOS: M.Glaser (PH-DT) M.Moll

4 The RD50 Collaboration 41 European institutes Belarus (Minsk), Belgium (Louvain), Czech Republic (Prague (3x)), Finland (Helsinki, Lappeenranta ), France (Paris, Orsay), Germany (DESY, Dortmund, Erfurt, Freiburg, Hamburg, Karlsruhe, Munich(2x)), Italy (Bari, Florence, Perugia, Pisa, Torino), Lithuania (Vilnius), Netherlands (NIKHEF), Poland (Krakow, Warsaw(2x)), Romania (Bucharest (2x)), Russia (Moscow, St.Petersburg), Slovenia (Ljubljana), Spain (Barcelona(2x), Santander, Valencia), Switzerland (CERN, PSI), Ukraine (Kiev), United Kingdom (Glasgow, Liverpool) Collaborators from several experiments at the LHC: ATLAS, CMS and LHCb and also from ILC Cross-experiment discussions 6 North-American institutes Canada (Montreal), USA (BNL, Fermilab, New Mexico, Santa Cruz, Syracuse) 1 Middle East institute Israel (Tel Aviv) 1 Asian institute India (Delhi) 49 institutes and 280 members + 22 observers Workshops Irradiation facilities 24t h Workshop in Bucharest, t h Workshop in Freiburg, 2009 More details on: 4

5 Challenge: Radiation Damage in the upgrade of LHC Planned upgrade of the LHC to HL-LHC (and beyond) For HL-LHC in ~2024: 3000 fb-1 expected integrated luminosity (x6 nominal lumi.) Expected particle fluences for the ATLAS Inner tracker: Pixel damage due to neutrons and pions, strips mainly due to neutrons Exposure up to 2*101 6 neq/cm2 Further requirements for detectors: - High occupancy high granularity - Low material budget thin detectors I. Dawson, P. S. Miyagawa, Sheffield University, Atlas Upgrade radiation background simulations RD50 investigates understanding of radiation damage of sensors and aims for development of devices to cope with these requirements 5

6 Defect Characterization Aim: Identify defects causing change of detector properties, namely trapping, leakage current and Ne f f (Vd e p) use knowledge for device engineering and input to simulations charged defects, Vd e p, Ne f f Tools: Defect Analysis on many identical samples performed with the various tools in RD 50 Collaboration C-DLTS (Capacitance Deep Level capture e, h trapping generation e,h leakage current Defect parameters: cross section, ionization energy, concentration, type Example: Dependence of leakage current on annealing Transient Spectroscopy) I-DLTS (Current Deep Level Transient Spectroscopy) TCT (Transient Current Technique) TSC (Thermally Stimulated Current) CV/IV (Capacity/Voltage vs. Current).. A. Junkes PoS(Vertex2011)035 Tests after irradiation with protons, neutrons, electrons and 60Co-gammas and before and after annealing Leakage current decreases after annealing, temperature dependent DLTS result due to defects E4/E5 and E205a 6

7 Defect Characterization Overview WODEAN (Workshop on Defect Analysis in Silicon Detectors) since charged at RT Phosphorus VO -/0 shallow dopant (pos. Charge) V2 -/0 +/- charged at RT positive charge P 0/+ BD 0/++ Ip 0/- E30K 0/+ (higher introduction after proton irradiation than after neutron irradiation) positive charge =/E205a -/0 E4 E5 -/0 (high concentration in oxygen rich material) leakage current + neg. charge Achievements (some): Consistent set of defects after different irradiations Defect introduction rates depend on particle type and energy H152K and E205a indicated to contribute significantly to trapping (current after γ irradiation) H152K 0/H140K 0/H116K 0/- Reverse annealing CiOi+/0 Boron: shallow dopant (neg. Charge, contribution increases with ann., cluster related) B 0/- (neg. Charge) Point defects extended defects Defects act as trapping centers and reduce collected charge G. Casse, M.Moll, LHCC report 2012, R. Radu 24th RD50 Workshop, June 2014 I.Pintilie et al., Appl. Phys. Lett ,

8 Simulation group in RD50 Goal: development of approach for simulation of performance of irradiated silicon detectors using custom and professional software TCAD input Simulations needed to predict electric fields (double junction), trapping Using effective mid gap levels in simulation (bulk damage using 2 or 3, surface damage by placing fixed charges Qf at SiO2/Si interface) Deep Acceptor (-/0) Large parameter space needs tuning to experimental TCT results (introduction rates, cross sections of defects) Deep Donor (0/+) Start to have predictive power For bulk: Ileak, Vfd, E-field, TCT and CCE, partially trapping of irradiated sensor For surface: Cint, Rint, position dependence of CCE Preliminary parametrization of model to predict CCE Tuning to predict E-field profile and compare with Edge-TCT results CCE from simulation vs. testbeam (by CMS Collab.): Fixed values of Qf predict CCE Aim to prepare common database with cross sections, concentrations N-in-p FZ 320 μm and MCz and FZ 200 μm sensors T. Peltola, PSD

9 Detector characterization and full detector systems: Planar FZ detectors Task: Systematic evaluation of strip and pixel sensors connected to fast electronics before and after irradiation with protons, neutrons, pions and gammas Selection of geometry and material N-in-p FZ after proton, neutron and gamma irradiation, beta source tests after 80 min annealing at 60 C G.Casse, VERTEX 2008 (p/n-fz, 300μm, (-30 C, 25ns) I.Mandic et al., NIMA 603 (2009) 263 (p-fz, 300μm, -20 C to -40 C, 25ns) n-in-p performs best (brought forward by RD50): No space charge inversion Favourable combination of weighting and electric field after irradiation: maxima at same electrode Readout at n-type electrodes: collection of electrons (fast), shorter trapping times, enhance amount of charge S. Wonsak, 25th RD50 Workshop Nov N-in-p baseline for upgrade of ATLAS and CMS silicon strip tracking detectors (in current detectors p-in-n) 9

10 New structures: Thin FZ detectors Thin detectors less material FZ sensors of different thickness and with 450 μm edge, ATLAS FEI4, 25 MeV protons, beta source Collected charge of FZ pixel sensors to doses of up to 14*101 5 neq/cm2 S. Terzo, 24rth RD50 Workshop June μm thick sensors show saturation of collected, thicker devices underdepleted 200 μm collects more charge than 285 μm at moderate voltages ( V) for fluences above 1*101 5 neq/cm2 40% CCE for 200 μm thick device beam tests show 97-99% hit efficiency (100 μm active edge sensor, 300V, 5*101 5 neq/cm2) Sensor modules still functional (though inhomogenous irradiation) B. Paschen, 25rth RD50 Workshop Nov

11 New Structures: Slim/active edge sensors Minimize dead area of sensors: several techniques SCP slim edges Exploits scribe and cleave technique on planar and 3D devices, passivated edge Laser, XeF2 etch, DRIE etch, saw cut Tweezers, new: Dynatex machine V. Fadeyev et al, NIM A 731 (2013) 260 V. Fadeyev, 23rd RD50 Workshop Nov CIS n-in-p, 285 μm thick, 150 μm slim edge, 800 V bias, 4*1015 neq/cm2 Native Oxide + Radiation or PECVD (n-type), ALD (p-type) PTI (V. Eremin) & CERN (G. Ruggiero, NIM A604, 2009, ) VTT/MPI active edges project Pixel sensors with slim edges, trenches doped by four-quadrant implantation FE-I3 FZ silicon, 100 μm thick, 125 μm slim edge, threshold: 1500 e - Sr90, Alibava, single cluster plot Hit efficiency ( )% at 300 V after S. Terzo, 23 RD50 Workshop Nov *1015 neq/cm2 rd Similar median charge as for other strips Also under development at HPK Overall efficiency, Ileak and noise unaffected by edge-cutting 11

12 New Structures: 3D sensors 3D sensors: Doped columns double-sided vertical to surface Decoupling of depletion voltage and detector thickness (collected charge) but have low-field region Allows slim edge Intensively studied in RD50 Collaboration and others S. Parker et al. NIMA 395 (1997) 328 A. Zoboli et al., IEEE TNS 55(5) (2008) 2775 G. Giacomini, et al., IEEE TNS 60(3) (2013) 2357 G. Pellegrini, NIM A 592 ( 2008) sketch of CNM sensor with filled columns Efficiency in test beam of CNM sensors: mean 97.5% Signal efficiency vs. fluence R. Mori, 23rd RD50 Workshop Nov ATLAS Collab. JINST 2012, 7 P11010 Well performing and detectors from CNM and FBK installed in ATLAS IBL Fluence neq/cm2 12

13 New Structures: HVCMOS Investigations within RD50 started recently HVCMOS devices: Depleted active pixel detectors implemented in CMOS process Sensor element is deep n-well in low resistivity (~10 Ωcm) p-type substrate Depletion with 60 V ~ 10 μm charge collection via drift of ~1000 electrons, short time Pixel and strip detectors possible Edge-TCT measurements to understand charge collection properties Bumps due to amplifier Diffusion HVCMOSv3 Edge-TCT laser beam HVCMOS from I-Peric connected to FEI4 readout chip Drift scan in y fast readout amplifier Collection behaviour confirmed M. Fernandez, 25th RD50 Workshop, Nov

14 New Structures: HVCMOS after irradiation Several HVCMOS devices tested after neutron irradiation: Edge-TCT signal integrated for t < 3 ns Drift component contributes before and after irradiation similarly Edge-TCT signal integrated for 3 ns < t < 25 ns Collected charge after irradiation lower due to low E-field in bulk After highest dose reduced collected charge (by 50%) although depletion width similar to unirradiated but trapping M. Fernandez, 25th RD50 Workshop, Nov V=60 V at RT, laser resolution ~8 μm C. Weisser, 25th RD50 Workshop, Nov

15 Full detector systems: Charge Multiplication Charge multiplication observed after irradiation to 2-5*101 5 neq/cm2 Characterized with different techniques and in different type of devices 3D sensors n-in-p Diodes Strip sensors n-in-p G. Casse, NIM A, 624(2011), M. Köhler, NIM A, 659 (2011), , 16th RD50 Workshop, June 2010 J. Lange, NIM A 622 (2010) 49, 16th RD50 Workshop, June 2010 Charge Collection (Beta source, Alibava readout) Origin: Irradiation leads to high negative space charge concentration in detector bulk increase of the electric field close to n-type strips impact ionization Goals: Simulation and prediction of charge multiplication Long term, S/N behaviour Exploit charge multiplication by junction and device engineering - Dedicated R&D in RD50 to understand and optimize multiplication mechanism - Production of new sensors 15

16 Charge Multiplication: Long term Behaviour and Enhancement Long term behaviour of multiplication effect: 15 2 HPK strip sensor, mixed irradiated to 2.1*10 neq/cm and annealed 4200min@RT Production of sensors with trenches: 5, 10, 50 μm deep, 5 μm wide in center on n+ electrode G. Casse, NIM A 669 (2013) 9-13, P. Fernández-Martínez, NIM A 658 (2011) HV off 1h 60 C HV off S. Kuehn, 10th Trento Workshop, 2015 Charge multiplication observed After long term biasing and subsequent CCE measurements drop in charge seen (observed by several groups) Partial recovery after 1 day without bias or temperature treatment (1h at 60 C) No full recovery of charge After 5*1015 neq/cm2 neutrons, n-in-p sensor 300 μm thick CCE higher for sensors 5 and 50 μm trenches compared to standard sensors 16

17 New Structures: Low Gain Avalanche Diodes LGAD Diodes with implemented multiplication layer (deep p+ implant): n++-p+-p-p+ to increase S/N with internal gain and readout with std. front-end M. Baselga, 8th Trento Workshop, 2013 H. Sadrozinski, 25th RD50 workshop, Nov N-in p detector with p-doped diffusion (Boron) under cathode enhanced E-field multiplication layer Uniform implantion required to avoid aprupt changes in E-field Edge termination needed: low doping n-well Several samples under test: Gain of up to ~20 before irradiation Current and noise independent of gain TCT measurements match simulation and show dependence of multiplication on Neff Thinner substrates (50 μm) enhance time resolution of devices, new devices under test (N. Cartiglia & H. Sadrozinski, 25th RD50 workshop, Nov. 2014) G. Kramberger, 24nd RD50 workshop, June

18 New Structures: Low Gain Avalanche Diodes LGAD irradiated Multiplication effect degrades after irradiation, gain reduces to ~1.5 neutron irradiation proton irradiation (800 MeV p) G. Kramberger, 24th RD50 workshop, June 2014 W8: boron implant 2*1013 cm2 Reason for reduced charge and lower gain: Removal of boron in p-type layer, no trapping effect Reduced electric field removal of initial acceptors (more than in std. diodes) More degradation after proton irradiation (800 MeV p) Noise scales with multiplication Gain dependeds on temperature (high T, low gain) Additional bulk damage from radiation New technology development required for p-type multiplication layer: Approach to replace Boron with Gallium (heavier, lower penetration depth but higher diffusion coefficient) Potential for fast timing under investigation 18

19 Summary RD50 is a CERN R&D collaboration: inter-experiment exchange of knowledge, irradiation campaigns, test beams and common wafer and sensor projects, common tools and test systems Aiming for radiation hard silicon detectors for future collider experiments Many topics covered and organised in different research lines Defect characterization: Detailed understanding of microscopic defects, consistent list Simulation working group: Simulation results get predictive power, common database Full detector systems: Plenty of data on n-in-p-type allowing recommendations for silicon tracking detectors at HLLHC. Slim/active edges deployable option. Thin segmented sensors extend fluence range Detector Characterization: Charge multiplication effect systematically investigated to allow its exploitation new structures (trenches, LGAD, geometry width/pitch, fast detectors) New Structures developed, produced and tested: Slim/active edges: Production controlled and pixel close to edge highly efficient 3D-detectors: Highly performing and deployed in ATLAS experiment HVCMOS: Few samples tested, drift signal changes barely after irradiation, diffusion signal and trapping reduce charge (50% charge after 2*1016 neq/cm2). LGAD-sensors: Uniform gain of up to 20 before irradiation, decrease after irradiation due to boron (acceptor removal). Good electrical performance. New devices with optimized geometry and Ga in preparation Thin, low-r strip sensors,... Several talks and posters in this session give more details on new structures 19

20 Conclusion Very active community and many projects ongoing! More on Thank you to all colleagues for material! 20

21 Backup 21

22 Achievements of RD50 in light of LHC experiments Observed radiation damage in LHC experiments agrees with predictions developed by RD50 Leakage current increase in ATLAS, depletion voltage evolution in LHCb Recommendations for silicon tracking detectors at HL-LHC Inner layers with fluences of about 1*101 6 neq/cm2 planar sensors collect decent amount of charge, hit efficiency 97% n-in-p (or n-in-n) candidate material (important collection of electrons) thin detectors overcome problem of requirement of high bias voltage, advantageous with doses > 1*101 5 neq/cm2 3D detectors are alternative option and show good performance with lower bias voltage (used now in IBL of ATLAS experiment) Outer layer with fluences of about 2*101 5 neq/cm2 planar FZ n-in-p sensors baseline for ATLAS and CMS upgrade strip tracker (FZ has reverse annealing after > 12 weeks at room temperature) MCz also option, damage is compensated in mixed fluences, long-term beneficial annealing (50 weeks at room temperature). Double column 3D detectors developed within RD50 with CNM and FBK option for pixel detectors 22

23 Change of Ileak Dependence of leakage current for high doses HPK mini strip detectors S. Wonsak, 24th RD50 Workshop June 2014 Leakage current scales with fluence α = 4.38*10-17A/cm up to ~1*1015 Neq/cm2 for higher doses non-linear 23

24 Impact of Defects: Change of Neff Dependence on particle type: proton vs. neutron irradiation Effect of reverse annealing after irradiation 2*101 4 neq/cm2 Epi-DOsilicon I.Pintilie et al., NIM A 611 (2009) TSC result: Donor E(30K) introduces positive space charge after proton irradiation Violates NIEL hypothesis! Introduces more positive space charge in oxygen rich material A. Junkes PoS(Vertex2011)035, I. Pintilie et al., APL 92, (2008) TSC result: Acceptors H(116K), H(140K), H(152K) increase with reverse annealing H(116K) might depend on oxygen concentration increase of negative space charge 24

25 Defect Characterization Defect parameters: charged defects, Vd e p, Ne f f capture e, h trapping I. Pintilie/ R. Radu, 23rd RD50 Workhshop, Nov

26 New structures: Mcz vs. FZ MCz with [O] ~ 5*1017 cm-3 (introduced by RD50) Sensors 200 μm thick, 1.5*101 5 neq/cm2 protons MCz performs better than FZ MCz less affected by annealing, stable annealing behaviour Improved performance in mixed fields due to compensation of neutron and charged particle damage in oxygen rich MCz MCz FZ G. Steinbrück, 23rd RD50 Workshop Nov

27 Detector Characterization: Investigation of Electric Fields with Edge-TCT Goal: Measurement of electric field in unirradiated and irradiated devices, usual TCT (Transient Charge Technique) not working due to trapping after irradiation Edge-TCT, G. Kramberger, IEEE TNS, VOL. 57, NO. 4, AUGUST 2010, 2294 N.Pacifico, 20th RD50 Workshop, 2012 G. Kramberger, 5th Trento Workshop, 2010 Example: n-on-p strip detector (pitch 80 μm), irradiated to 1*101 6 neq/cm2, with protons, no annealing I(y,t~0) proport. ve+vh Different drift velocity in FZ and MCZ silicon N.Pacifico, 20th RD50 Workshop, 2012 MCZ FZ 27

28 Full detector systems: Goals and Tools Systematic evaluation of strip and pixel sensors connected to fast electronics before and after irradiation with protons, neutrons, pions Use fast (40 MHz) analogue or binary readout electronics Determine parameters like collected charge, noise, signal-to-noise by using beta source set-ups, laser setups and test beams Design and realization of pixel/strip detectors in contact with manufacturers (CiS, CNM, HIP, HPK, Micron, Sintef) ALIBAVA daughter board with detector RD50 test beam setup (additional to other setups in the Collaboration (EUDET, CMS)) Based on ALIBAVA system with analogue fast readout Device under test and sensors for track reconstruction run with same readout Allows easy handling and high resolution measurements 28

29 Edge-TCT: Lifetime of charges Estimate and Understand with TCT measurements the charge life time T. Pöhlsen, 20th RD50 Workshop, 2012 T. Peltola, 23rd RD50 Workshop Nov

30 Trenches a standard, b poly trench including poly silicon doped with phosphorus, c p-layer with p-type diffusion, d oxide trench P. Fernández-Martínez, NIM A 658 (2011)

31 New Structures: Further 3D sensors Further development: 3D-Trench Electrode Detector (BNL&CNM) Overcomes low-field region in 3D detectors First sample V ~95 V after FD 1*1016 neq/cm2 Uniform electric field Full charge collected by 241Am source test Next: position-resolved laser tests A. Montalbano et al., E. Vianello, 6th Trento Workshop,

32 New Structures: LGAD Doping : Distance G. Pellegrini, 24th RD50 Workshop, Nov Distance 32

33 Full detector systems: p-type Detectors Example: FZ n-in-p ministrip sensors (HPK 300 μm thick, 80 μm pitch), tested with beta source, readout with ALIBAVA system (40 MHz) and irradiated with pions, protons and neutrons π Collected charge after 2*1015 Neq/cm2 and annealing p 1100V π p 1000V π 800V p n n 600V 400V 200V S. Kuehn, 21rd RD50 Workshop Nov Collected charge reduces at 600 V to 9.0±0.7 ke (~40%) After 2.8*101 5 neq/cm2: signal-to-noise ratio 12.3±0.1 Different steps of annealing visible Collected charge stable until 320 min (~120 days at room temperature) no reverse annealing Enhancement of charge multiplication after 2560 min for voltages above 800 V 33