1. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 1 Development of Radiation- tolerant p-type Silicon Microstrip Sensor Y. Unno for the joint collaboration of the R&D collaboration in Japan, the ATLAS R&D collaboration of "Development of non-inverting Silicon strip detectors for the ATLAS ID upgrade", and Hamamatsu Photonics K.K.

2. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 2 A Challenge Ahead SLHC –> x10 higher instaneous luminosity 300-400 pile-up events 20 (LHC) –> x4 integrated luminosity 6,000 fb -1 700 fb -1 (LHC) SCT PIXEL Particle fluences in ATLAS inner detector (ID) – ~1x10 15 1-MeV neq/cm 2 @ R ~30 cm, Z~150 cm –Charged : n < 1:1 –Neutrons: ~5x - 3x 10 14 1-MeV neq/cm 2 @ R ~30 cm - 90 cm

3. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 3 Some History of Development 2006 p-type 6-inch (150 mm) wafer (ATLAS06) –FZ1(100)(~6.7k Ωcm) –FZ2(100)(~6.2k Ωcm) –MCZ(100)(~2.3k Ωcm) 2007 p-type 6-inch (150 mm) wafer (ATLAS07) –FZ-1(100)(~6.7k Ωcm) –FZ-2(100)(~6.2k Ωcm)

4. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 4 ATLAS06 p-type Sensors 6 inch (150 mm) wafer –FZ1 (100), FZ2 (100), MCZ Many miniature (1cm x 1cm) sensors –One sensor per one "Zone" Large (3cm x 6 cm) sensors with 2 striplets –Variation of Polysilicon bias resistor connections R&D of n-strip isolation –Width of (common) p- stop –p-stop/p-spray doping concentrations

5. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 5 ATLAS07 p-type Sensors 6-inch (150 mm) wafer –FZ1, (FZ2) Full size (9.75 cm x 9.75 cm) prototype sensors –4 segments: two "axial" and two "stereo" (inclined) strips R&D's –n-Strip Isolation –"Punch-thru Protection" structures –Wide/Narrow metal effect –Wide/Narrow pitch effect

6. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 6 Results of ATLAS06 Evaluations –Irradiation at CYRIC (70 MeV protons) Fluences: 2, 5, 20, 30 x10 14 1-MeV neq/cm 2 –C-V and Laser (1064 nm) Results –FZ vs MCZ Full depletion voltages Annealing –n-Strip isolation

7. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 7 FZ vs MCZ - FDV Development Proton damage Full depletion voltages (FDV) –Laser CCE –(No MIP evaluation yet) No significant diffence is observed in FZ (FZ1 or FZ2) or MCZ ATLAS06 CCE

8. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 8 FZ vs MCZ - Annealing Annealing –2x10 14 Samples Larger reverse annealing component in MCZ C-V Using fixed beneficial and reverse annealing time constants

9. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 9 n-Strip Isolation Isolation voltage –at 10% over saturated current Degradation observed >2x10 14 neq/cm 2 –MCZ is the best N+N+ P-bulk SiO 2 N+N+ 1.5MΩ A P-stop Al 5V5V Bias voltage

10. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 10 ATLAS07 1st batch - PTP mini PTP miniature sample –Onset of Microdischarge ~300V –Hot spot identified Source of trouble understood –TCAD simulation - 2nd p-stop –To be corrected in the mask Other zones (Z3) –Onset of MD >600 V –Something else in trouble?

11. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 11 ATLAS07 1st batch - Main Main sensors –MD onset ~400 V Hot spot identified, Source of trouble understood - Asymmetric

12. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 12 TCAD Simulation - 2nd p-stop Y. Unno et al., IEEE08 Conf. record –Potential of 2nd p-stops makes effective p-stop width as wide up to 2nd p-stop –N-P gap was too narrow

13. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 13 TCAD Simulation - Asymmetric Wide pitch –Potential of p-stop is deep Asymmetric placement of p- stop –Potential of p-stop is nearly as same as the symmetric –Electric field of the narrow gap is steeper Steeper than the same gap of the symmetric placement of p- stop

14. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 14 ATLAS07-II Onset of Microdischarge is expelled >1,000V –not only diodes (bottom group) and miniatures (middle group) –but also the main sensor (10 cm x 10 cm) (top line)! More than single sample –Two wafers are shown We/Vendor have established the basic technology –of the radiation tolerant p-type sensor that requires ~1,000V operation –Now the issue is the "Yield" (in the vendor) –For us, to validate the performance After irradiation Strip isolation PTP protection

15. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 15 Measurement with  -ray Slit (0.5 mm) x Absorber(0.5mm Al) –Trigger rate ~20 Hz 4 readout channels –Peaking time ~40 ns 90Sr : 2.28 MeV   = p/m = 5.4 0.5mm Al absorber DUT Sr90 Scinti 0.5mm 2mm 10mm 3.4mm 3mm 5mm 5 mm x 5 mm

16. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 16 Charge [fC] No. Events ＨＶ＝１００ Ｖ ＨＶ＝５８０ Ｖ Collected Charge CCE with  ＣＨ １ ＣＨ ２ ＣＨ ３ ＣＨ ４ Event selection: "No signal" in CH1 and CH2 (Cut: 0.6 fC) Sum of CH1+CH2

17. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 17 CCE with  ATLAS07-II Fluences –p: 2, 5, 10 x10 １４ neq/cm 2 –n: 2, 5, 10 x10 １４ neq/cm 2 Collected charges –of neutrons > of protons –Something is happening to neutrons? –or to protons? –NO MD in I-V up to the max. voltage H. Hatano et al. (U. Tsukuba+KEK)

18. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 18 CCE and FDV with Laser ATLAS07-II Proton irradiation –0.15, 2.0, 5.0,10.0 x10 14 neq/cm 2 –Annealed for 80 min. at 60 °C Laser-CCE –beta-CCE to be made soon Vmax Vmin (Pulse height)^2 S. Mitsui et al. (U. Tsukuba + KEK)

19. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 19 CCE - Fluences and Radii beta-CCE (ATLAS07-II) Fluence dependence of neutrons and protons –seems different but needs further study –~linear dependence on flunece CCE as a function of radius –>70% at 500 V, >80% at 800V

20. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 20 Strip Isolation -  irradiation Degradation of strip isolation –Severe in < 2 kGy (< 200 krad) –Caution for the surface charge-up –(not shown but) MCZ seems worse than FZ K.Hara et al., IEEE08 Conf. Record ATLAS06 (FZ1) and ATLAS07-I (FZ1)

21. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 21 PT Protection ATLAS-II samples Before irradiation –V_ptp ~ 30 V (where the resistance becomes ~1/2) After p 1.0x10 15 neq/cm 2 –V_ptp ~ 30 V M. Yamada et al. (U. Tsukuba + KEK) Non irrad

22. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 22 Summary Basic technology for the radiation tolerant p-type silicon microstrip sensor is established –V MD > 1,000 V for a 10 cm x 10 cm large area sensor! No real advantage of the p-MCZ wafer to the p-FZ wafer, available in Japan –:-| Similar FDV development along irradiation –:-< Larger FDV till dominated by the radiation induced acceptor components –:-< Larger reverse-annealing component –:-) Better strip isolation, but :-< rapid variation in  irrad. CCE by n or p still has to be understood –Collected charges in neutron damage is larger than in proton damage Evaluation with irradiation of ATLAS07-II has started

23. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 23 Backup

24. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 24 Proton Irradiation at CYRIC Facility associated with Univ. Tohoku, Sendai, Japan Beamline 32 Beamline 31-2 KEK 70 MeV protons

25. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 25 Proton irradiations at CYRIC AVF Cyclotron at Tohoku University –Beam energy: 70 MeV –Beam intensity: 10nA ~ 800nA –Beam spot size: ~5 mm FWHM ~4 min. for 1x10 15 at 800 nA Irradiation history –Beamline 31-2 2005.10.17 - 1st and beamline study ATLAS05 - up to 5x10 15 – 2006.01.27 +2006.03.14 +2006.06.26 + 2006.10.16 ATLAS06 - up to 2x10 15 –2007.05.18, –Beamline 32 –2007.08.28 ATLAS07 - up to 1x10 15 –2008.03.11 Change of beamline –Machine time/user conflict in 31 –Straight, simpler line in 32 Beamline 31-2 Beamline 32

26. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 26 Laser for FDV and CCE Full Depletion Voltages (FDV) –C-V method –Laser method Charge Collection Efficiencies (CCE) –Laser method Pulsed laser (1064nm) focused to 4um x 4um Reference sensor

27. Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 27 I-V of Neutron-irradiated Samples n 1x10 15 1-MeV neq/cm 2 No microdischarge up to 1,000V