1. 18.7.2003General Tracker meetingA. Furgeri 1 Irradiation results and Annealing scenarios for HPK IEKP – University of Karlsruhe Alexander Furgeri Alex.furgeri@web.de

2. 18.7.2003General Tracker meetingA. Furgeri 2 Outline Overview of relevant sensor parameters Main results from p-irradiation prequalification W1TID-, IB1- and W3- Wafers for irradiation in Louvain Results from irradiation in Louvain Scenarios of U dep for inner Barrel sensors Conclusions

3. 18.7.2003General Tracker meetingA. Furgeri 3 Parameters of sensors Resistivity:expected to be varying from 1.25 to 3.25kΩcm Full depletion voltage: Effect of thickness: 320µm  290µm (30µm n + -layer) ~19% less depletion voltage ! Higher resistivity  lower depletion voltage For allowed range of resistivity: 130V < U dep <350V

4. 18.7.2003General Tracker meetingA. Furgeri 4 Differences diodes  sensors The depletion voltage for sensors are also depending from geometrie factors. The lowest is : ~1.16 (IB1) The highest is : ~1.31 (W3) Only HPK!

5. 18.7.2003General Tracker meetingA. Furgeri 5 Changes of Rpoly after irrad + 0.35 MΩ + 0.15 MΩ n-doped poly-Si  Increase of Rpoly due to donor removal HPK with high fluenceST with low fluence

6. 18.7.2003General Tracker meetingA. Furgeri 6 Changes of CC after irrad - 15pF HPK –sensor with high fluence For minis ~ -1pF, Difficult to see due to fluctuations of measurements with 100Hz.

7. 18.7.2003General Tracker meetingA. Furgeri 7 Results from proton irradiation Small increase of Rpoly small decrease of CaC small increase of Cint (for allowed flatband voltage range! Defined from studies in KA) Rint above limit (introduced measurement signal below noise) NO PINHOLES !!! NO LEAKY STRIPS !

8. 18.7.2003General Tracker meetingA. Furgeri 8 Development of U dep Changes of N eff : –short term annealing –stable Damage –long term reverse annealing

9. 18.7.2003General Tracker meetingA. Furgeri 9 Experimental data for donor removal in Hamburg model HPK with high fluence r C =N C,0 /N eff,0 Describes complete or partial donor removal r C <1 ! Results from KA p-irradiation

10. 18.7.2003General Tracker meetingA. Furgeri 10 Special n-irradiation (high res.) Irradiation in Louvain of IB1,W3 & W1TID –Check for resistivity profile across wafer, (before irradiation) –Check if sensors follow the Hamburg model ! –Adjusting parameters and taking into account for scenarios –Check of new measurement methods of Louvain (Rpoly!) and cross check with Karlsruhe

11. 18.7.2003General Tracker meetingA. Furgeri 11 Resistivity explained by HPK HPK delivered sensors with to high resistivity. Explanation from HPK: Wafers have a large variation of resistivity across wafer profile! But also sensors with a resistivity of >5kΩcm (70V) appeared in the community. Question: where does the depletion voltage end?

12. 18.7.2003General Tracker meetingA. Furgeri 12 Prequalification W1TID Diodes 2-5 and 10-13 not measurable breakdown for diodes between 460V and 530V depletion voltage for diodes: 50V (for all !) depletion voltage for minis: 80V (~1.3*U dep of diodes ?!) Depletion voltage for sensor 105V (profile of HPK seems to be right) Same profile for W3

13. 18.7.2003General Tracker meetingA. Furgeri 13 Irradiation in Louvain r c ~ 0,3 (0.65) g c ~ 1,2e-2 (1.49e-2) Only diodes choosen for adjusting the hamburg model! Reason: variation in correction Factors diodes↔Sensors due to resistivity profile!

14. 18.7.2003General Tracker meetingA. Furgeri 14 Irradiation in Louvain Check if minisensors follow the Hamburg Model with the new exp. data!

15. 18.7.2003General Tracker meetingA. Furgeri 15 Irradiation in Louvain Check if sensors follow the Hamburg model! g c ~1.1e-2 ? r c ~0.3 !

16. 18.7.2003General Tracker meetingA. Furgeri 16 Cross check Louvain  KA Very good agreement for minisensors ! For sensors discrepances in Cint and CC!

17. 18.7.2003General Tracker meetingA. Furgeri 17 Batches with high resistivity HPK delivers sensors with high resistivity –higher depletion voltage in the end of CMS expected –Luminosity in the tracker 1. year 10% 2. year 33% 3. year 67% 4.-10. year 100% –Sensor fluence in reality depending from the location in the tracker Radial location (especially for charged Hadron fluence) Z-location (especially for neutron fluence in the endcaps)

18. 18.7.2003General Tracker meetingA. Furgeri 18 Fluence distribution in the tracker Low variation in fluence for most geometries. geometryFluence [10e14-1MeV] Charged Hadrons / neutrons IB1 – 1. LayerIB1 – 2. Layer1.26 / 0.330.67 / 0.32 IB20.4 / 0.2 W1TID1.02 / 0.35 W11.02 / 0.35 W20.65 / 0.4 W30.4 / 0.6 - 0.22 / 0.6 W40.3 / 0.32 - 0.2 / 0.6 Uncertanties in fluences: 50%

19. 18.7.2003General Tracker meetingA. Furgeri 19 Calculation of the scenario Local Distribution of fluence in the Tracker –Tracker-TDR –comparison with E. Migliore (same source ?!) Fluences for different geometries Per year: 1.Irradiation (at once) 2.Beneficial annealing (10°C & 20°C) 3.Reverse annealing (10°C & 20°C) Scenario for 10 years time without beam and annealing not shown

20. 18.7.2003General Tracker meetingA. Furgeri 20 Time constants for HH For +20°C:τ A =2.3 days τ y =475 days For +10°C: τ A =10 days τ y =2920 days For –10°C:no significant change for 10 years To avoid reverse annealing keep temperature as low as possible!

21. 18.7.2003General Tracker meetingA. Furgeri 21 Differences A. Furgeri  E. Migliore A. Furgeri –28 days per year @ 20°C 5 Times higher time constant for beneficial annealing –Donor removal (r C ) from experimental data in Karlsruhe and Louvain (better for low resistivities, less uncertainties) –g c from exp. data –Geom. factors for sensors, confirm with exp. Data –Factor of 1.5 for fluences E. Migliore –28 days per year @ 10°C 26 times reduced time constant for reverse annealing –Complete donor removal for hadron fluences (worse for low resistivity, but not confirm with exp. data) –g c from literature –No correction factor (diodes instead of sensors) –No factor for uncertainties in fluences

22. 18.7.2003General Tracker meetingA. Furgeri 22 What‘s the allowed maximum for depletion voltage? Max. 600V from power supplies Factor of 1.5 for over depletion needed  Maximum for depletion voltage of 400V ?! Let‘s look where we are !

23. 18.7.2003General Tracker meetingA. Furgeri 23 Description for following plots Before type inversionAfter type inversion Real scenario

24. 18.7.2003General Tracker meetingA. Furgeri 24 Scenarios IB1 – 1. Layer Worst case for IB1, thickness 320µm, Annealing @20°C 14 days, Maximum 440V  With actual thickness of 290µm: 360V Remember U dep ~ d² Effect of higher resistivity: ~30V

25. 18.7.2003General Tracker meetingA. Furgeri 25 Scenarios IB1 – 1. Layer Worst case for IB1, with thickness 320µm, 28 days @20°C per year Maximum 530V  With actual thickness of 290µm: 435V

26. 18.7.2003General Tracker meetingA. Furgeri 26 Scenarios IB1 – 1.Layer Worst case for IB1, with thickness 320µm, 28 days @ 10°C per year  d= 290µm  320V

27. 18.7.2003General Tracker meetingA. Furgeri 27 Scenarios W1 TEC & TID 14 days @ 20°C Maximum 400V 28 days @ 20°C Maximum 470V   d= 290µm  380Vd= 290µm  320V

28. 18.7.2003General Tracker meetingA. Furgeri 28 Scenarios IB1 – 2.Layer 14 days @ 20°C Maximum 290V 28 days @ 20°C Maximum 330V

29. 18.7.2003General Tracker meetingA. Furgeri 29 Scenarios W2 14 days @ 20°C Maximum 320V 28 days @ 20°C Maximum 390V  d= 290µm  315V

30. 18.7.2003General Tracker meetingA. Furgeri 30 Sceanrios W3 14 days @ 20°C Maximum 290V 28 days @ 20°C Maximum 350V d= 290µm  250V

31. 18.7.2003General Tracker meetingA. Furgeri 31 Different donor removal in worst case scenario Donor removal of 65% for ch. Hadrons and 30% for neutrons, due to exp. data Complete donor removal for ch. Hadrons and 65% for neutrons Not confirm with exp. data Effect of 40V for high res. 100v for low res.

32. 18.7.2003General Tracker meetingA. Furgeri 32 Discrepances IQC and Scenarios Result after IQC (no exp. data!)  No reverse annealing! Scenario for IB1- 1.Layer Effect of reverse annealing ~200V!

33. 18.7.2003General Tracker meetingA. Furgeri 33 Summary of uncertainties Donor removal ? Irradiation in Lubljana in progress (9 minis) for different fluences. (higher statistic) Temperature during shutdown and repair periods ? –CONDITIONS CONTROLLED ?! –Avoid reverse annealing ! Try to keep temperature below 20°C !  max. of +10°C for 4 weeks?! Time of shutdown and repair periods ? –Open (warm up) the Tracker as late as possible ! Fluences in different running periods ? Effectiv thickness of sensors ? Changes in production? … Ask me again after 10 years!

34. 18.7.2003General Tracker meetingA. Furgeri 34 Conclusions Worst case for IB1,(W1TEC & W1TID?) needs ~700V bias voltage, but expected to be better Separation of sensors with different resistivities possible for IB1 (1. & 2. Layer) No separation possible for W1 and W1TID IB2,W2,W3 & W4 not critical (high res. accepted) Question of high resistivity: Sensors accepted, with compromise, that the next sensors of IB1 will have a lower resistivity (1.25-2 kOhmcm)