1. 1 Summary of the radiation hardness studies of MAPS @IKF 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

2. /17/27 Applications of MAPS Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 2 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

3. /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 10 12 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 2013 3 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

4. /17/27 Operation principle of MAPS Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 4 +3.3V Output SiO 2 N+ P+ P- P+ Diode Epitaxial Layer P-Well Source Follower

5. /17/27 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 5 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, 2007. "Quantification of Actinide α-Radiation Damage in Minerals and Ceramics." Nature 445(7124):190-193.

6. /17/27 Leakage current Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 6 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

7. /17/27 Thermal annealing against ionizing radiation Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 7 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) 133-136

8. /17/27 Cooling against non-ionizing radiation Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 8 Cooling Noise is alleviated to a factor of 2 with decreasing temperature. Radiation damage

9. /17/27 Non-ionizing radiation damage effect Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 9 Charge losses due to recombination at radiation-induced defects e- Particle Defects due to radiation Epitaxial Layer Diode

10. /17/27 Influence of radiation damage and pixel pitch Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 10 e- Large pixel pitch Small pixel pitch Defects due to radiation Small pixel pitch Large pixel pitch Epitaxial Layer Diode Epitaxial Layer Diode

11. /17/27 Pixel pitch effect Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 11 In most of the cases, the whole charge can be detected. Little losses for larger pixel pitch even unirradiated

12. /17/27 Pixel pitch effect Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 12 Signal losses depend on the pixel pitch.

13. /17/27 Pixel pitch effect Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 13 Smaller pixel pitch improves radiation tolerance. Drawback: Number of pixel Readout time Power consumption Michael Deveaux, PHD-Thesis

14. /17/27 High-resistivity Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 14 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

15. /17/27 Signal to Noise ratio Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 15 Error bars: Fit uncertainty + 10% noise uncertainty S/N limit (MIPS) High-resistivity

16. /17/27 Signal to Noise ratio Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 16 Error bars: Fit uncertainty + 10% noise uncertainty S/N limit (MIPS) High-resistivity

17. /17/27 Radiation tolerance Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 17 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

18. /17/27 Parasitic surface damage after neutron irradiation Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 18 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

19. /17/27 MVD-prototyp sensor: MIMOSA-26 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 19 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

20. /17/27 Ionizing radiation of MIMOSA-26 20 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

21. /17/27 Non-ionizing radiation of MIMOSA-26 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 21 High-resistivity: After 10 13 n eq /cm² approximately the same CCE as Low-resistivity non-irradiated

22. /17/27 Beam test results of MIMOSA-26 by IPHC Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 22 High-resistivity irradiated better efficiency than low-resistivity non-irradiated! IPHC

23. /17/27 Summary of MIMOSA-26 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 23 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 10 12 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

24. /17/27 Going to a smaller feature size Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 24 - 0.18µm 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

25. /17/27 Signal to noise ratio Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 25 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)

26. /17/27 Beam test result by IPHC Strasbourg Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 26 CBM SIS100 0.18µm MIMOSA-32 Rad. hard. non-io. >10 13 n eq Rad. hard. io > 1 Mrad Radiation hardness requirements of CBM@SIS100 achieved by MIMOSA-32. IPHC

27. /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 10 12 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 2013 27 -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

28. /17/27 Acknowledgement Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 28 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

29. /17/27 Summary Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 29 -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

30. /17/27 Conclusion Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 30 High-resistivity Smaller feature size Radiation damage: Ionizing Radiation damage: Non-ionizing

31. /17/27 Progress in sensor development Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 31 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 10 12 n eq Rad. hard. io > 1 Mrad200 krad Time resolution < 30 µs~ 1 ms *Optimized for one parameter

32. /17/27 Non-ionizing radiation: High-resistivity Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 32 Shown: DPG Mainz 2012 HK 12.8 Paper in preparation for publication High resistivity epitaxial layer increases radiation hardness by one order of magnitude

33. /17/27 Ionizing radiation: 0.18µm process Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 33 CBM SIS100 0.18µm MIMOSA-32 Rad. hard. non-io. >10 13 n eq Rad. hard. io > 1 Mrad

34. /17/27 Progress in sensor development Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 34 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 10 12 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

35. /17/27 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 35 High-resistivity0.18µm process

36. /17/27 CMOS Monolithic Active Pixel Sensors Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 36 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 10 12 >10 13 Rad. hard. io. [krad] > 1 000200> 500 Time resolution < 30 µs~ 1 ms110 µs

37. /17/27 CMOS Monolithic Active Pixel Sensors Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 37 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 10 12 >10 13 Rad. hard. io. [krad] > 1 000200> 500Smaller oxid layers Time resolution < 30 µs~ 1 ms110 µsMore complex logic possible

38. /17/27 Ionizing rad. Damage: Signal to Noise ratio Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 38 Preliminary Critical limit Signal to Noise ratios seem sufficient even after 10Mrad

39. /17/27 Open issues: Noise tails Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 39 Mi32TER

40. /17/27 Open issues: Noise tails Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 40 Mi32TER Probable origin: 1/f-noise

41. /17/27 Deep Pwell: PMOS-transistors possible Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 41 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

42. /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 2013 42 Mi32TER Deep P-Well Diode PMOS-Transistor (simplified) d

43. /17/27 Ionizing rad. damage: Response to MIPs Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 43 As expected: No influence on the response Zeigen?

44. /17/27 Noise and fake hit rate Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 44 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

45. /17/27 Vary the transistor size Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 45 Mi32TER

46. /17/27 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 46 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

47. /17/27 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 47

48. /17/27 Fake hit rate (transistor size) Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 48 Small transistor => dramatically higher fake hit rate

49. /17/27 A possible explanation Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 49 N Pixel per bin hottest pixel ~50e hottest pixel > 80e Small gate => wide noise distribution => many hot pixels

50. /17/27 Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 50 WidthLengthNoise [ADU] (20°C, +/-10%) Gain [e/ADU] (20°C) Noise [ENC] (20°C, +/-10%) ELT1.8512.122.4 1.5 µm0.2 µm1.8711.120.8 0.9 µm0.2 µm2.1510.522.5 0.5 µm0.2 µm2.4110.124.3 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

51. /17/27 Applications of MAPS Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 51 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).

52. /17/27 Operation principle Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 52 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 10-40 µm => a few µm resolution

53. /17/27 Operation principle Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 53 SiO 2 N+ P+ P- P+ Epitaxial Layer P-Well Substrate e- N+ e- Particle Sensing diode

54. /17/27 Non-ionizing radiation effects: Signal response Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 54 SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate N+ e- Sensing diode Defects

55. /17/27 Signal response Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 55

56. /17/27 Non-ionizing radiation effects: Leakage current/Noise Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 56 SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate N+ - - Sensing diode Defects

57. /17/27 Noise Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 57 Radiation damage

58. /17/27 Noise Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 58 Radiation damage

59. /17/27 Noise Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 59 Radiation damage Cooling 2 times higher noise with respect to unirradiated

60. /17/27 Non-ionizing radiation effects Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 60 SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate N+ e- - - Sensing diode Defects

61. /17/27 Non-ionizing radiation effects Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 61 SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate N+ e- - - Radiation damage Sensing diode Defects

62. /17/27 Non-ionizing radiation effects Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 62 SiO 2 N+P+ P- P+ Epitaxial Layer P-Well Substrate N+ e- - - Radiation damage Sensing diode Defects

63. /17/27 Signal to Noise ratio Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 63 S/N limit (MIPS) Technical feasible limits reached: - Pixel pitch - Operating temperature Region of interest ?

64. /17/27 High-resistivity Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 64 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

65. /17/27 Signal response Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 65

66. /17/27 Signal response Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 66 More charge collected in a high resistivity epitaxial layer.

67. /17/27 Signal response Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 67 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.

68. /17/27 Improvements using high resistivity Dennis Doering: Status of radiation tolerance of MAPS CBM Coll Meeting GSI April 2013 68 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

69. /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 2013 69

70. /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 2013 70