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Status report St & HPK plus add. Scratch tests.

Status report St & HPK plus add. Scratch tests. IEKP – University of Karlsruhe Frank Hartmann. QTC (sensors from JAN & FEB). Optical inspection of KA-Set 10 &11 (33/35) Electrical results of KA-Set 10/1 W5B (8/8) KA-Set 10/2 W5B (13/13) KA-Set 11/1 W6B (5/10)

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Status report St & HPK plus add. Scratch tests.

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  1. Status report St & HPK plus add. Scratch tests. IEKP – University of Karlsruhe Frank Hartmann Sensor meeting

  2. QTC (sensors from JAN & FEB) • Optical inspection of KA-Set 10 &11 (33/35) • Electrical results of • KA-Set 10/1 W5B (8/8) • KA-Set 10/2 W5B (13/13) • KA-Set 11/1 W6B (5/10) • KA-Set 11/2 W6B (4/4) • KA-Set H5 W1TID (3/37) • Some high IV  “I-t” • Some currents are improving with time • MANY sensors at the IV limit • Possible explanation for the high IV and discrepancy of CMS & ST measurements. Sensor meeting

  3. Optical inspection KA-S10/1 Batch 31850 W5B Del. 9.1.2003 KA-S10/2 Batch 37528 W5B (11/13) Del. 9.1.2003 KA-S11/2 Batch 39728 W6B 9.1.2003 KA-S11/1 Batch 32961 W6B 9.1.2003 Sensor meeting

  4. 2 Sensors class „C“ 30211023185021 30211023752820 IV OK!  2 rejects! Sensor meeting

  5. KA Set S10 (21 sensors W5B) Sensor meeting

  6. KA Set S10 ---- global Sensor meeting

  7. KA Set S11 (9/14 sensors W5A) Sensor meeting

  8. KA Set S11 ---- global Sensor meeting

  9. Comparison of Datas • For 17 sensors no data available ! (~50% data still missing!!!!!!) • Good agreement for pinholes, shorts and Rpoly! • Ileak & CaC not measured by ST • Add. defective strips have scratches! • no add. Pinholes due to scratches! • Higher current @ 450V due to scratches! • QTC & ST agree on IV up to the additional ~linear~ increase! Sensor meeting

  10. Same IV up to “soft strip breakdown” First strip Second strip Sensor meeting

  11. Summary of QTC preliminary Sensor meeting

  12. I-t @ 450V 10µA 1. 5 µA 7 µA 2. Saturation not yet reached 5 µA Sensor meeting

  13. I-t @ 550V 12 µA 8 µA Min not reached! Sensor meeting

  14. I-t @ 550V over night 30211223972812 Sensor meeting

  15. Improvements of IV e.g. 30211023752813 I-t (~10 min) between each IV-curve ! Sensor meeting

  16. IV-problem • 5 from 6 sensors improved, but… • they needed ~20 min or longer to reach the specified limit! • each sensor has a few „high leaky“ strips! • Σ leaky strips ~ IV ( few strips drive IV) • EACH leaky strip is scratched ! Attention: standard test with “I-t” would had have jected 6 instead of 1 Sensor meeting

  17. Leaky strips 30211223972812 strip 49 30211223972812 strip 282 Sensor meeting

  18. Leaky strips (2) 30211223972812 strip 282 30211223972816 strip 3 Sensor meeting

  19. Leaky strips (3) ? 30211223972816 strip 14 30211223972816 strip 476 Sensor meeting

  20. Solving/Explaining the problem!?!??? • Clear correlation between IV and leaky strips and scratches on sensors observed! • No IV-breaks on Minisensors !  Handling !  Scratch test: • Scratchtest on minisensors to reproduce effect • Needle • Pencil (2B) • screwdriver Sensor meeting

  21. Scratches on Minisensor „Soft“ scratches with probe needle Carbon residues of pencil Sensor meeting

  22. Deep scratches on Minisensor „Not-so-SOFT“ scratches with screwdriver Sensor meeting

  23. IV of ST-minisensor x3 Sensor meeting

  24. ILeak (regard strips 8-15) A few single strips show high leakage current! Sensor meeting

  25. Ileak ramps on scratched strips x70 All ramps on screwdriver scratched minisensor! The ramp behavior is similar to the global IV! Sensor meeting

  26. Correlation  strip current  IV Undamaged minisensor @ 400V: Ileak ~ 0,2nA x 192 strips ~ 35nA IV ~ 38nA Damaged minisensor @ 400V:  Ileak damaged strips ~ 55nA  Ileak all ~ 100nA IV ~ 120nA High IV behavior is driven by some leaky strips ! Sensor meeting

  27. Similar defect in CDF sensorsDefect in the p+ layer!! BUT: scratches do not effect p+ ( no pinholes!) Sensor meeting

  28. Idiel on scratched Minisensor Pinholes should be here ! Effect is located in the Al layer, above the oxide! Sensor meeting

  29. Summary of scratch-test • Scratches increase individual strip leakage current • Some few leaky strips drive high IV • “Hard” mechanical force necessary to damage sensor! • ALL unscratched minisensors show GOOD IV ! • ALL leaky strips are scratched, but not all scratched strips are leaky ! • Pinholes??? • no pinholes produced in scratch-test • no big differences between data of ST and QTC (w.r.t. pinholes) •  Effect is located in the Al layer, not the p+ layer  CMS sensors have metal strip overhang!!!! Sensor meeting

  30. HPK W1TID qualification • PQC fine, but quite low depletion voltages • BTC OK • Masks: postponed -- should be done in Vienna, cause CMM breakdown in KA • QTC: fine, but quite low depletion voltages! • Very low total leakage currents. • 3/27 sensors measured (no single strip failure) Sensor meeting

  31. KA SET H5 (3/37 W1TID) Sensor meeting

  32. KA SET H5 --- global Sensor meeting

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