1 Summary of the radiation hardness studies of Frankfurt AD AD vanced MO MO nolithic S S ensors for IKF Frankfurt: Dennis Doering*, Samir Amar-Youcef, Alexander Büdenbender, Michael Deveaux, Melissa Domachowski, Ingo Fröhlich, Michal Koziel, Qiyan Li, Borislav Milanovic, Christian Müntz, Bertram Neumann, Sarah Ottersbach, Paul Scharrer, Christoph Schrader, Christian Trageser, Tobias Tischler, Michael Wiebusch, Joachim Stroth IPHC Strasbourg: J. Baudot, N. Chon-Sen, G. Claus, C. Colledani, R. De Masi, A. Dorokhov, G. Dozière, W. Dulinski, M. Gélin, M. Goffe, A. Himmi, C. Hu-Guo, K. Jaaskelainen, F. Morel, C. Santos, M. Specht, I. Valin, S. Senyukov, M. Winter

/17/27 Applications of MAPS Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Picture STAR Picture CBM International Linear Collider CBM-Experiment (FAIR, GSI) STAR-Experiment MAPS are developed for applications as vertex detector since 1999 at IPHC (Strasbourg). Possible ITS-Upgrade ALICE

/17/27 CBM SIS300 MAPS* (2003) Strategy Single point res. ~ 5 µm1.5 µmBinary readout Material budget* < 0.3% X 0 ~ 0.1% X 0 Thinning to 50µm Rad. hard. non-io. >10 13 n eq n eq Pixel pitch & high-resistivity Rad. hard. io > 3 Mrad200 kradAnnealing & smaller feat. size Time resolution < 30 µs~ 1 msMassiv parallel readout Strategy road map Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Used by industry (digital camera) Have been modified for charged particle detection since 1999 by IPHC Strasbourg Foreseen for STAR, CBM, ALICE, ILC… => Sharing of R&D costs. *With/without support

/17/27 Operation principle of MAPS Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April V Output SiO 2 N+ P+ P- P+ Diode Epitaxial Layer P-Well Source Follower

/17/27 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Classesof radiation damage Classes of radiation damage To be investigated and improved: Radiation hardness against… … ionizing radiation: Energy deposited into the electron cloud Can ionize atoms and destroy molecules Caused by charged particles and photons … non-ionizing radiation: Energy deposited into the crystal lattice Atoms are displaced Caused by heavy (fast leptons, hadrons), charged and neutral particles Farnan I, HM Cho, WJ Weber, "Quantification of Actinide α-Radiation Damage in Minerals and Ceramics." Nature 445(7124):

/17/27 Leakage current Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Reset +3.3V Output SiO 2 N++ N+ P+ P- P+ SiO 2 Positive Charge Leakage current generated by defects of the irradiation is collected => Noise generated

/17/27 Thermal annealing against ionizing radiation Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Thermal annealing to suppress ionizing damage without drawbacks in reverse annealing Annealing at +20°C neglected Dennis Doering et al. Annealing studies on X-ray and neutron irradiated MAPS, NIM-A 658 (2011)

/17/27 Cooling against non-ionizing radiation Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Cooling Noise is alleviated to a factor of 2 with decreasing temperature. Radiation damage

/17/27 Non-ionizing radiation damage effect Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Charge losses due to recombination at radiation-induced defects e- Particle Defects due to radiation Epitaxial Layer Diode

/17/27 Influence of radiation damage and pixel pitch Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April e- Large pixel pitch Small pixel pitch Defects due to radiation Small pixel pitch Large pixel pitch Epitaxial Layer Diode Epitaxial Layer Diode

/17/27 Pixel pitch effect Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April In most of the cases, the whole charge can be detected. Little losses for larger pixel pitch even unirradiated

/17/27 Pixel pitch effect Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Signal losses depend on the pixel pitch.

/17/27 Pixel pitch effect Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Smaller pixel pitch improves radiation tolerance. Drawback: Number of pixel Readout time Power consumption Michael Deveaux, PHD-Thesis

/17/27 High-resistivity Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Larger depleted volumes: ⇒ Accelerated charge collection ⇒ Improved non-ionizing radiation tolerance SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate depleted volume Low-resistivity ~ 30 Ωcm High-resistivity ~1k Ωcm New CMOS process available: High-resistivity: Decrease of doping concentration in epitaxial layer. Sensing diode

/17/27 Signal to Noise ratio Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Error bars: Fit uncertainty + 10% noise uncertainty S/N limit (MIPS) High-resistivity

/17/27 Signal to Noise ratio Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Error bars: Fit uncertainty + 10% noise uncertainty S/N limit (MIPS) High-resistivity

/17/27 Radiation tolerance Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April D. Doering et al. Pitch dependence of the tol. of MAPS to non-ionizing radiation. Submitted to NIM A. Pixelpitch dependent non-ionizing radiation tolerance improved by one order of magnitude

/17/27 Parasitic surface damage after neutron irradiation Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Michael Deveaux, Dennis Doering et al. Effect of parasitic surface damage in neutron irradiated MAPS, in prep. for publ. Noise contribution identified, alleviated after thermal annealing Master thesis Paul Scharrer

/17/27 MVD-prototyp sensor: MIMOSA-26 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April JTAG slow control On-chip voltage regulators 1152 discriminators zero suppr. logic Output memories 21.2 x 10.6 mm² 18.4 µm pixel pitch Pixel column Digital part Sensing part

/17/27 Ionizing radiation of MIMOSA Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 MIMOSA-26: Limitation of ionizing radiation to a few hundert kRad. MIMOSA-26 do not fulfill the CBM requirements of ionizing radiation tolerance

/17/27 Non-ionizing radiation of MIMOSA-26 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April High-resistivity: After n eq /cm² approximately the same CCE as Low-resistivity non-irradiated

/17/27 Beam test results of MIMOSA-26 by IPHC Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April High-resistivity irradiated better efficiency than low-resistivity non-irradiated! IPHC

/17/27 Summary of MIMOSA-26 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April CBM SIS300 MAPS* (2003) MIMOSA-26 Binary, 0 Single point res. ~ 5 µm1.5 µm4 µm Material budget < 0.3% X 0 ~ 0.1% X 0 ~ 0.3% X 0 Rad. hard. non-io. >10 13 n eq n eq >10 13 n eq Rad. hard. io > 3 Mrad200 krad> 500 krad Time resolution < 30 µs~ 1 ms110 µs MIMOSA-26 successfully used for the MVD prototype Michael Deveaux, Dennis Doering et al., Radiation tolerance of a column parallel CMOS sensor with high resistivity epitaxial layer, JINST 6 (02) (2011) C02004

/17/27 Going to a smaller feature size Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April µm has a much more larger intrinsic ionizing radiation tolerance than 0.35µm - Still drawbacks in noise. Status: Origin identified, being fixed with opimized transistor layout Transistor layout in 0.18µm not yet optimized for noise Dennis Doering et al. Abstract submitted for IWORID 2013

/17/27 Signal to noise ratio Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Signal to noise ratio well above the critical value of 15.  Expect tolerance to 3Mrad, plausibly also to 10Mrad. (Both to be confirmed in a beam time)

/17/27 Beam test result by IPHC Strasbourg Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April CBM SIS µm MIMOSA-32 Rad. hard. non-io. >10 13 n eq Rad. hard. io > 1 Mrad Radiation hardness requirements of achieved by MIMOSA-32. IPHC

/17/27 CBM SIS300 MAPS* (2003) MAPS* (2013) MIMOSA-26 Binary, 0 Single point res. ~ 5 µm1.5 µm1 µm4 µm Material budget < 0.3% X 0 ~ 0.1% X 0 ~ 0.05% X 0 0.3% X 0 Rad. hard. non-io. >10 13 n eq n eq >3·10 14 n eq >10 13 n eq Rad. hard. io > 3 Mrad200 krad> 3 Mrad> 500 krad Time resolution < 30 µs~ 1 ms~ 25 µs110 µs Summary Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Thermal annealing established to suppress ionizing radiation damage effects -Improved non-ionizing radiation hardness by more than one order of magnitude (HR) -Improved ionzing radiation hardness by more than one order of magnitude (0.18µm) -Demonstrated that the MVD-prototyp sensor Mimosa26 fulfill non-io requirements of CBM - 4 paper published or in preparation to be published - To Do: Integrate „everything“ in one sensor

/17/27 Acknowledgement Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Thanks to IKF Frankfurt: Samir Amar-Youcef, Ingo Fröhlich, Michal Koziel, Qiyan Li, Borislav MMichael Deveaux, Melissa Domachowski, ilanovic, Bertram Neumann, Sarah Ottersbach, Paul Scharrer, Christoph Schrader, Christian Trageser, Tobias Tischler, Joachim Stroth, Michael Wiebusch IPHC Strasbourg: Jerome Baudot, Mathieu Goffe, Sergey Senyukov, Marc Winter

/17/27 Summary Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Thermal annealing established to suppress ionizing radiation damage effects -Improved non-ionizing radiation hardness by more than one order of magnitude (HR) -Improved ionzing radiation hardness by more than one order of magnitude (0.18µm) - Demonstrated that the MVD-prototyp sensor Mimosa26 fulfill non-io requirements of CBM - 4 paper published or in preparation to be published

/17/27 Conclusion Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April High-resistivity Smaller feature size Radiation damage: Ionizing Radiation damage: Non-ionizing

/17/27 Progress in sensor development Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April CBM SIS100 MAPS* (2003) Single point res. ~ 5 µm1.5 µm Material budget < 0.3% X 0 ~ 0.1% X 0 Rad. hard. non-io. >10 13 n eq n eq Rad. hard. io > 1 Mrad200 krad Time resolution < 30 µs~ 1 ms *Optimized for one parameter

/17/27 Non-ionizing radiation: High-resistivity Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Shown: DPG Mainz 2012 HK 12.8 Paper in preparation for publication High resistivity epitaxial layer increases radiation hardness by one order of magnitude

/17/27 Ionizing radiation: 0.18µm process Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April CBM SIS µm MIMOSA-32 Rad. hard. non-io. >10 13 n eq Rad. hard. io > 1 Mrad

/17/27 Progress in sensor development Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April CBM SIS100 MAPS* (2003) MAPS* (2012) Single point res. ~ 5 µm1.5 µm1 µm Material budget < 0.3% X 0 ~ 0.1% X 0 ~ 0.05% X 0 Rad. hard. non-io. >10 13 n eq n eq >3·10 14 n eq Rad. hard. io > 1 Mrad200 krad> 1 Mrad Time resolution < 30 µs~ 1 ms~ 25 µs *Optimized for one parameter High-resistivity 0.18µm process See: HK 9.5 Mo 12:15: Dennis Doering: MAPS in 0.18µm process This Session

/17/27 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April High-resistivity0.18µm process

/17/27 CMOS Monolithic Active Pixel Sensors Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April CBM SIS100 MAPS (2003) 0.35µm (2010) Single point res. ~ 5 µm1.5 µm4 µm Mat. budget [X 0 ] < 0.3%~ 0.1%~ 0.05% Rad. hard. non-io. [n eq /cm²] > >10 13 Rad. hard. io. [krad] > > 500 Time resolution < 30 µs~ 1 ms110 µs

/17/27 CMOS Monolithic Active Pixel Sensors Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April CBM SIS100 MAPS (2003) 0.35µm (2010) 0.18µm (2012) Single point res. ~ 5 µm1.5 µm4 µm Mat. budget [X 0 ] < 0.3%~ 0.1%~ 0.05% Rad. hard. non-io. [n eq /cm²] > >10 13 Rad. hard. io. [krad] > > 500Smaller oxid layers Time resolution < 30 µs~ 1 ms110 µsMore complex logic possible

/17/27 Ionizing rad. Damage: Signal to Noise ratio Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Preliminary Critical limit Signal to Noise ratios seem sufficient even after 10Mrad

/17/27 Open issues: Noise tails Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Mi32TER

/17/27 Open issues: Noise tails Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Mi32TER Probable origin: 1/f-noise

/17/27 Deep Pwell: PMOS-transistors possible Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April No change in charge spectrum observed,  It is allowed to operate a PMOS transistors without drawbacks in charge collection P7: deep pwell everywhere Mi32TER Deep P-Well Diode PMOS-Transistor (simplified) d

/17/27 Deep PWell hampers charge collection, reduces depleted zone of diode. Recovered for d=10µm: Size of the diode hole? Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Mi32TER Deep P-Well Diode PMOS-Transistor (simplified) d

/17/27 Ionizing rad. damage: Response to MIPs Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April As expected: No influence on the response Zeigen?

/17/27 Noise and fake hit rate Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Threshold: 5 x noise Noise increases with decreasing transistor size. Fake hit rates increases despite of noise adapted thresholds => Non Gaussian No clear temperature trend =>1/f noise? Mi32TER ELTStdSmallTiny SF Transistor size ELTStdSmallTiny SF Transistor size

/17/27 Vary the transistor size Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Mi32TER

/17/27 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Deep P-Well Diode PMOS-Transistor (simplified) d No DPWell d= 6µm d=10µm For d=6µm, the depletion depth and the CCE is slighly reduced Mostly recovered for d=10µm

/17/27 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April

/17/27 Fake hit rate (transistor size) Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Small transistor => dramatically higher fake hit rate

/17/27 A possible explanation Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April N Pixel per bin hottest pixel ~50e hottest pixel > 80e Small gate => wide noise distribution => many hot pixels

/17/27 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April WidthLengthNoise [ADU] (20°C, +/-10%) Gain [e/ADU] (20°C) Noise [ENC] (20°C, +/-10%) ELT µm0.2 µm µm0.2 µm µm0.2 µm Small gate => 10% more gain Small gate => 25% more noise Small gate => 20% more noise Noise standard: PedestalFinal In TOWER 0.18µm: Small gate => Few more gain Small gate => Substantially more noise

/17/27 Applications of MAPS Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Picture STAR Picture CBM International Linear Collider CBM-Experiment (FAIR, GSI) STAR-Experiment MAPS are developed for applications as vertex detector since 1999 at IPHC (Strasbourg).

/17/27 Operation principle Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April SiO 2 N+ P+ P- P+ Sensing diode Epitaxial Layer P-Well Substrate N+ 50 µm ~50 µm thin sensors ⇒ low material budget High granularity ⇒ good spatial resolution µm => a few µm resolution

/17/27 Operation principle Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April SiO 2 N+ P+ P- P+ Epitaxial Layer P-Well Substrate e- N+ e- Particle Sensing diode

/17/27 Non-ionizing radiation effects: Signal response Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate N+ e- Sensing diode Defects

/17/27 Signal response Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April

/17/27 Non-ionizing radiation effects: Leakage current/Noise Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate N+ - - Sensing diode Defects

/17/27 Noise Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Radiation damage

/17/27 Noise Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Radiation damage

/17/27 Noise Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Radiation damage Cooling 2 times higher noise with respect to unirradiated

/17/27 Non-ionizing radiation effects Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate N+ e- - - Sensing diode Defects

/17/27 Non-ionizing radiation effects Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate N+ e- - - Radiation damage Sensing diode Defects

/17/27 Non-ionizing radiation effects Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate N+ e- - - Radiation damage Sensing diode Defects

/17/27 Signal to Noise ratio Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April S/N limit (MIPS) Technical feasible limits reached: - Pixel pitch - Operating temperature Region of interest ?

/17/27 High-resistivity Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Larger depleted volumes ⇒ guided charge collection ⇒ Improved charge collection efficiency (CCE) SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate depleted volume Low-resistivity High-resistivity High-resistivity: Decrease of doping concentration in epitaxial layer. Sensing diode

/17/27 Signal response Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April

/17/27 Signal response Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April More charge collected in a high resistivity epitaxial layer.

/17/27 Signal response Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Radiation damage effect after 3·10 14 n eq /cm²: Some signal get lost due to recombinations. However, the high resistivity sensor is even irradiated better than the low resistivity sensor unirradiated.

/17/27 Improvements using high resistivity Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April Error bars: Signal fit uncertainty * 10% noise uncertainty *Beam test is pending S/N limit (MIPS) * Parameters: - Pixel pitch - Operating temperature - Resistivity of epitaxial layer

/17/27 How to improve the non-ionizing radiation hardness of MAPS: -Operate the sensor at low temperature ( -30°C) -Small pixel pitch ( 10µm) -High-resistivity epitaxial layer (used here 400 Ωcm) Conclusion Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April

/17/27 How to improve the non-ionizing radiation hardness of MAPS: -Operate the sensor at low temperature ( -30°C) -Small pixel pitch ( 10µm) -High-resistivity epitaxial layer (used here 400 Ωcm) ⇒ Radiation hardness beyond 3·10 14 n eq /cm² Conclusion Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April