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Introduction , P ast W ork and F uture Perspectives : A Concise Summary

Introduction , P ast W ork and F uture Perspectives : A Concise Summary. CERN, 18.02.2013 Arno E. Kompatscher CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH Erfurt, Germany. Contents. Personal Introduction Diploma Thesis General outline Crystallography

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Introduction , P ast W ork and F uture Perspectives : A Concise Summary

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  1. Introduction, PastWork andFuture Perspectives: A Concise Summary • CERN, 18.02.2013 • Arno E. Kompatscher • CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH • Erfurt, Germany

  2. Contents • Personal Introduction • Diploma Thesis • General outline • Crystallography • Martensite • Preparation • Analysis and results • TEM bright field • TEM selected area diffraction (SAD) • DSC • Conclusions

  3. Contents • Present Work and Future • 4’’ wafer layout • 6’’ wafer layout • Comparison • Quad vs. FE-I4 vs. FE-I3 • Ganged & long pixels (Quad, center) • With and without long pixels (edge) • Bias grid variations • Prospects

  4. PersonalIntroduction • Arno E. Kompatscher • Born June 4, 1984 in Hall in Tirol • Hometown: Feldkirch, Vorarlberg • Studiedphysicsat University of Vienna • Thesis: ElectronmicroscopyofNi-Mn-Gaalloys • Mag.rer.nat. (= M.Sc.) on August 28, 2012

  5. Personal IntroductionHome & Education

  6. Personal IntroductionCurrent Work • Since November 1, 2012: • Early Stage Researcher • CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH • Erfurt, Thuringia • Ph.D. via • Prof. Claus Gößling • Lehrstuhl Experimentelle Physik IV • TU Dortmund, North Rhine-Westphalia

  7. Diploma Thesis “Phase transformations in Ni-Mn-Ga shape memory alloys subjected to severe plastic deformation” Supervisor: Prof. Thomas Waitz Group: Physics of Nanostructured Materials (PNM) Faculty of Physics, University of Vienna physnano.univie.ac.at

  8. Diploma ThesisGeneral Outline • Material: • Ni54Mn25Ga21 • Tetragonal martensite (2M) in initialstate • Preparation: • High pressure torsion (HPT) • Annealing (heat treatment) • Analysis • Transmission electron microscopy (TEM) • Differential scanning calorimetry (DSC) • X-ray diffractometry(XRD)

  9. Diploma ThesisCrystallography Austenite (L21Heusler) Martensite (I4/mmm, bct)

  10. Diploma ThesisMartensite • Martensiticphasetransformation • Displacive, diffusionless, 1st order • Low temperaturemartensite • High temperatureaustenite

  11. Diploma ThesisMartensite Different variantsofmartensite Unmodulated (2M, initialstate), Modulated (7M and 5M)

  12. Diploma ThesisPreparation d = 0.4±0.1 Degreeofdeformation : 2.2 · 105 % and 6.5 · 105 % High pressuretorsion (HPT): 8 GPa, 50 and 100 turns

  13. Diploma ThesisAnalysis • Transmission electronmicroscopy (TEM) • Microstructure, grainsize, latticestructure, latticeparameters • Differential scanningcalorimentry (DSC) • Heattreatment, ID ofphasetransitionsandrespectiveenthalpies • X-Ray diffractometry (XRD) • Confirmationoflatticestructuresandparameters

  14. Diploma ThesisAnalysis Initial Material: w/o HPT, w/o heattreatment As deformed: after HPT, w/o heattreatment After HPT, heattreatmentto 420°C After HPT, heattreatmentto 500°C

  15. Diploma ThesisTEM brightfield Initial state As deformed Eachmartensiticvariant isinternallytwinned; grainsizeseveralhundredsofm Strong grainfragmentation due tosevereplasticdeformation (SPD)

  16. Diploma ThesisTEM brightfield HT 420°C HT 500°C Beginningsofgrainnucleation; smallpolygonizedgrainsstartto form due toheattreatment (arrows) Grainnucleationcompleted, clearlyidentifyablepolygonizedgrains; grainsize140±6 nm

  17. Diploma ThesisTEM SAD Initial state As deformed Disorderedtetragonal (fct), facecenteredcubic (fcc), nomartensite Tetragonal martensite

  18. Diploma ThesisTEM SAD HT 420°C HT 500°C Intermediadestructuredetected: disorderedbodycenteredcubic (bcc) 7M martensiteobservedtobepredominant

  19. Diploma ThesisDSC, initialstate AP = 208 °C MP = 190 °C

  20. Diploma ThesisDSC, progression • Change ofmartensiteandaustenitepeaktemperatures (AP, MP) due toheattreatment • Sample 1: shortannealing time (10 min at 500 °C, almostdirectly after HPT) • Sample 7: longannealing time (505 min attemperaturesfrom 500 to 675 °C)

  21. Diploma ThesisConclusions • HPT induces strong grainrefinement • Hundredsofm before HPT • 140±6 nm after HPT • HPT causesdisorderingandsuppressionofmartensitictransformation • Upon heattreatmentto 500 °C the adaptive 7M martensiticstructureforms

  22. Diploma ThesisAcknowledgement • Prof. Thomas Waitz, supervisor • Dr. Clemens Mangler, assistantsupervisor • PhysicsofNanostructured Materials (PNM) Group • FacultyofPhysics, University of Vienna • Materials Center Leoben (MCL) • Fonds zur Förderung der wissenschaftlichen Forschung (FWF)

  23. Present Workand Future

  24. Present Work & FutureMotivation Past: developmentofnewsensorsforinsertable B-layer (ATLAS Upgrade Phase I, happeningnow) Development ofnewdetectorsfor ATLAS Upgrade Phase II (2022)

  25. Present Work & Future4‘‘ Wafer • 2 x Quad • 3 x FE-I4 • Bias gridvariants • Long pixels (old) • Nolongpixels (new) • 8 x FE-I3 • Severalvariants • Special: w/o biasgrid • Test structures • Diodes • Temp. resistors • etc.

  26. Present Work & Future6‘‘ Wafer • 4 x Quad • 12 x FE-I4 • Bias gridvariants • Long pixels (old) • Nolongpixels (new) • 16 x FE-I3 • Severalvariants • Special: w/o biasgrid • Test structures • Diodes • Temp. resistors • etc.

  27. Present Work & FutureComparison

  28. Present Work & FutureComparison + – Problem: Higher riskoffracture Benefit: Larger areaofactivepixels

  29. Present Work & FutureGanged & longpixels

  30. Present Work & FutureGanged & longpixels

  31. Present Work & FutureComparison • w/ and w/o longpixels • Long pixels • Removed • Guard rings • Readjusted • Nowbelowstandardpixels • Benefits: • Slimmer design • Precision totheveryedge

  32. Present Work & FutureBias gridvariations • Problem: • High leakagecurrentsat HV • Possible Source: • Bias grid (dots) • Proposed Solution: • Varyingbiasgridlayout • Var. 1: biasdotsunchanged, grid per column • Var. 2: biasdotsunchanged, gridatpixelcenter • Var. 3: biasdotsandgridatpixelcenter • Control: nobiasgrid

  33. Present Work & FutureProspects Processing of 6‘‘ Wafers (CiS) Characterizationand Analysis (TU Dortmund) Test beam (DESY, Hamburg) Increasingradiationhardness

  34. ThankYouforyourattention

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