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  1. 1. Materials Characterization Lab www.mri.psu.edu/mcl Transmission Electron Microscopy (TEM) & Scanning Transmission Electron Microscopy (STEM) Joe Kulik 194 MRI Building juk12@psu.edu/814-865-0344 15 June 2005
  2. 2. Materials Characterization Lab www.mri.psu.edu/mcl Summer Characterization Open Houses Technique Time Date Location Thermal analysis (TGA, DTA, DSC) 9:45 AM June 8 250 MRL Bldg. Transmission Electron Microscopy (TEM/STEM) 9:45 AM June 15 114 MRI Bldg Scanning electron microscopy (SEM) 9:45 AM June 22 541 Deike Bldg. Analytical SEM 11:00 AM June 22 541 Deike Bldg. X-ray Diffraction (XRD) 9:45 AM June 29 250 MRL Bldg. Dielectric Characterization (25 min lecture only) 9:45 AM July 6 250 MRL bldg. High temperature sintering lab (20 min lecture only) 10:15 AM July 6 250 MRL Bldg. Focused Ion Beam (FIB) 9:45 AM July 13 114 MRI Bldg TEM sample preparation 11:00 AM July 13 114 MRI Bldg Orientation imaging microscopy (OIM/EBSD) 9:45 AM July 20 250 MRL Bldg. Chemical analysis (ICP, ICP-MS) 9:45 AM July 27 541 Deike Bldg. Atomic Force Microscopy (AFM) 9:45 AM August 3 114 MRI Bldg Small angle x-ray scattering (SAXS) 9:45 AM August 10 541 Deike Bldg. Particle Characterization 9:45 AM August 17 250 MRL X-ray photoelectron spectroscopy (XPS/ESCA) 9:45 AM August 24 114 MRI Bldg Auger Electron Spectroscopy (AES) 11:00 AM August 24 114 MRI Bldg NOTE LOCATIONS: The MRI Bldg is in the Innovation Park near the Penn Stater Hotel; MRL Bldg. is on Hastings Road. More information: www.mri.psu.edu/mcl
  3. 3. Materials Characterization Lab www.mri.psu.edu/mcl Materials Characterization Lab Locations Bldg Telephone MRL 863-7844 MRI 865-0337 MRI Bldg: Hosler 865-1981 XPS/ESCA, SIMS, E&ES 863-4225 TEM, HR-TEM, FE- Auger, AFM, XRD MRL Bldg: Hosler Bldg: SEM, XRD, OIM, DTA, SEM, ESEM, FE- DSC, TGA, FTIR, Penn Stater SEM, EPMA, ICP, Hotel Raman, AFM, Powder, E&ES Bldg: ICP-MS,BET, SAXS dielectric, prep, shop, SEM IC, UV-Vis Route 322 Steidle Bldg: Atherton Street Nanoindenter (322 Business) I-99 Park Ave. 0 0 0 0 0 0 0 Ave. 0 0 0 0 0 Park 0 Beaver 0 0 Stadium 0 0 0 Centre 0 0 Porter Road Community Univ Shortlidg Hospital 0 0 Burrowes Road ersi ty D e Pollock Road Road rive North Hastin Deike Bldg: gs Ro ad College Ave.
  4. 4. Materials Characterization Lab www.mri.psu.edu/mcl Outline ― Overview of TEM/STEM ―MCL capabilities ― Examples of applications from PSU investigations ― How to get started ― Campus resources ― a brief lab tour
  5. 5. Materials Characterization Lab www.mri.psu.edu/mcl Incident high-kV electron beam Secondary Backscattered electrons electrons Characteristic Auger Visible X-rays electrons light Thin Electron-hole ‘Absorbed’ Sample pairs electrons Bremsstrahlung X-rays Elastically scattered Inelastically electrons scattered electrons Direct beam
  6. 6. (Conventional) TEM Materials Characterization Lab www.mri.psu.edu/mcl Image Mode Electron Gun Diffraction contrast from dislocatios Condenser 1 Condenser 2 Specimen Objective High resolution of Objective twins in InP Aperture nanowires Intermediate Lens 1st Image Projector Lens 2nd Image Final Image
  7. 7. Materials Characterization Lab www.mri.psu.edu/mcl Diffraction Mode Diffraction pattern from ordered perovskite structure Final Diffraction Pattern
  8. 8. Materials Characterization Lab www.mri.psu.edu/mcl Scanning TEM (STEM) Scan Coils Front Focal Plane Condenser/Objective Specimen Field Region Back Focal Plane (BFP) Imaging of BFP to detector plane Dark field Bright field detector detector
  9. 9. Materials Characterization Lab www.mri.psu.edu/mcl X-ray Energy Dispersive Spectroscopy Reversed biased p-i-n junction n p i Electron-hole pairs Incident high-kV electron beam Output Characteristic V X-rays Thin Sample t
  10. 10. Materials Characterization Lab www.mri.psu.edu/mcl EDS Example
  11. 11. Materials Characterization Lab www.mri.psu.edu/mcl Electron Energy Loss Spectroscopy (EELS) Final microscope lens Loss spectrum Electron prism Detector spectrometer Quadrupole magnifiers Expanded spectrum
  12. 12. Materials Characterization Lab www.mri.psu.edu/mcl Philips EM420T Tungsten cathode Accelerating voltage: 120 keV Point-to-point resolution: 0.34 nm Objective Lens - Spherical aberration coef: 3.0 mm - Specimen tilt range: ±60° Energy dispersive x-ray spectroscopy (EDS) 10 mm2 detector area 140 eV resolution Spatial resolution: 5 nm Specimen Holders Single tilt Double tilt Heating Tmax = 900°C (single tilt) Cooling LN2 (double tilt)
  13. 13. Materials Characterization Lab www.mri.psu.edu/mcl JEOL JEM-2010 LaB6 Cathode Accelerating voltage: 200 keV Ultra high resolution pole piece (0.5 mm Cs) Point-to-point resolution: 0.20 nm Gatan TV rate camera Specimen Holders JEOL single tilt Gatan double tilt Stage tilt: +/-10° Energy dispersive x-ray spectroscopy (EDS) 30 mm2 detector area 140 eV resolution Spatial resolution: <2 nm
  14. 14. Materials Characterization Lab www.mri.psu.edu/mcl JEOL JEM-2010F Field emission gun Ultra high res pole piece (0.5 mm Cs) 1.9 Å point-to-point resolution Bright-field/dark-field STEM CCD camera Energy-Dispersive X-ray Spectroscopy EDAX Detector 138 eV resolution at Mn Ka 30 mm2 detector area Electron Energy Loss Spectroscopy (EELS) with 0.7 eV resolution Specimen Holders JEOL Single tilt low background holder Gatan Analytical holder with Be specimen cup Gatan Tilt-rotation holder with Be specimen cup Gatan Double tilt liquid nitrogen holder
  15. 15. Materials Characterization Lab www.mri.psu.edu/mcl Examples from PSU Research • BaTiO3 Dielectrics for capacitors, G.Y. Yang et al. • Shallow Ohmic Contacts to p-InAs for Heterojunction Bipolar Transistors, E. Lysczek, S. Wang J. Robinson, & S. Mohney • Au-Catalyzed Growth of Ge nanowires, T. Trammell, J. Kulik, & E. Dickey • Niobium Oxide Characterization with EELS, M. Olszta & E. Dickey • GaN Film on Composition-Graded AlGaN Buffer on Si, X. Weng & E. Dickey • Spectral Imaging of Si Nanowires, J. Wang et al. • Twinning Superlattice in InP Nanowires, J. Wang et al.
  16. 16. Materials Characterization Lab www.mri.psu.edu/mcl Microstructure of BaTiO3 Dielectric G.Y. Yang et al. 100 nm Conventional Perovskite 101 111 Structure: • as-produced BME capacitors 010 • Partial BaTiO3 grains in the degraded BME capacitors [101] Perovskite framework + modulation: • Most BaTiO3 grains in the degraded BME capacitors 100 nm Co-existence of the modulated and ordered structures • Some BaTiO3 grains in the degraded BME capacitors
  17. 17. Materials Characterization Lab www.mri.psu.edu/mcl Microstructure of BaTiO3 Dielectric G.Y. Yang et al. 101 111 111 010 (11 1) 2 nm 2 nm Modulated structure Long range ordered structure High-resolution TEM images of BaTiO3 in the degraded Ni-BaTiO3 MLCCs
  18. 18. Materials Characterization Lab www.mri.psu.edu/mcl Microstructure of BaTiO3 Dielectric G.Y. Yang et al. Relative chemical shift between the dielectric grains on different structural states indicating Ti reduction Ti L2,3 OK A BCD a. PME-as-produced MLC* BaTiO3.00 b. BME-as-produced MLC BaTiO2.93 c. BME-degraded regular BaTiO2.86 d. BME-degraded modulated BaTiO2.60 e. BME-degraded ordered BaTiO2.60 460 480 500 520 540 560 Energy-Loss (eV)
  19. 19. Materials Characterization Lab www.mri.psu.edu/mcl Microstructure of BaTiO3 Dielectric G.Y. Yang et al. (a) 7Å 111 111 2/ 2/ 2/ [0001]h // [111]p ⅔⅔⅔ 3 33 ⅓⅓⅓ /3 1/ 1/ 1 O 2- 33 Ba 2+ 000 Partially 000 Ti 3+ vacated O2- Ti 4+ site Superlattice: 7Å Ba(Ti4+1/3Ti3+2/3)O2.67 HRTEM images, structural model, and simulated image of long-range ordering structure of BaTiO3 in the Degraded Ni-BaTiO3 MLCCs
  20. 20. Materials Characterization Lab www.mri.psu.edu/mcl Pd/W/Au (3/50/145nm) Lysczek, Wang, Robinson, Mohney In Aged 250°C 9h Au • Reaction Depth = 6 ± 2 nm W • Some small voids present Pd-As, Voids • Indium out-diffusion InAs • Shallow and uniform reaction Buffer layer
  21. 21. Materials Characterization Lab www.mri.psu.edu/mcl Pd/Pt/Au (3/50/145nm) Lysczek, Wang, Robinson, Mohney Aged 250°C 9h Au • Reacted into buffer layer Pt • Uniform void formation at Voids interface Pt-In-As Buffer layer
  22. 22. Materials Characterization Lab www.mri.psu.edu/mcl Pt/W/Au (3/50/145nm) Lysczek, Wang, Robinson, Mohney Au W Pt-Au-In-As InAs Buffer Layer and Au Buffer Layer Aged 250°C 9h • Reaction Depth = 36 ± 7nm in areas without Au penetration • Tungsten diffusion barrier failed to keep Au out in one spot
  23. 23. Materials Characterization Lab www.mri.psu.edu/mcl Growth of Ge nanowires Trammell, Kulik, Dickey Identification of Au particles on Ge nanowires. E-beam probe size is < 1 nm.
  24. 24. Materials Characterization Lab www.mri.psu.edu/mcl Niobium Oxide Characterization with EELS M. Olszta, E. Dickey A 51500 B C CCD Photodiode Counts (a.u.) A B Counts (arb. units) D Nb2O5 C E 36500 D E NbO2 A 21500 NbO 6500 530.00 540.54 551.08 561.62 Energy Loss (eV)
  25. 25. Materials Characterization Lab www.mri.psu.edu/mcl GaN Film on Si via Composition-Graded AlGaN Buffer X. Weng, E. Dickey, J. Redwing 0002 Two-Beam Bright-Field Image GaN The composition-graded AlGaN buffer layer significantly reduces the threading dislocation density in the GaN film AlGaN 200 nm Si
  26. 26. Materials Characterization Lab www.mri.psu.edu/mcl Electron energy loss spectral image of a Si nanowire J. Wang et al. SiOx L3 map Si L3 map O K map 50 nm 1 2 Si+SiOx Si+SiOx SiOx SiOx Si L2,3 O K edge 100 200 300 400 500 Energy Loss (eV) SiOx L2,3 80 100 120 140 500 550 Energy Loss (eV) Energy Loss (eV)
  27. 27. Materials Characterization Lab www.mri.psu.edu/mcl Twinning Superlattice of InP J. Wang et al. [111] 5 nm
  28. 28. Materials Characterization Lab www.mri.psu.edu/mcl How to get started • Contact me (Joe Kulik) to discuss your needs • Attend training session – Sessions are by appointment – Informal – Typically 2 trainees per session • Provide budget and fund number! • TEM can be time consuming for beginners – If time is an issue, find a collaborator – There are many users at PSU
  29. 29. Materials Characterization Lab www.mri.psu.edu/mcl Sample preparation Material must be thin (< 100 nm) High resolution requires thickness ~20 nm Preparation methods: – Metals can be electropolished – Semiconductors and ceramics can be mechanically thinned followed by ion thinning to achieve electron transparency – Very fine grained powders, nanowires, nanoparticles can be dispersed on a support film (e.g., lacey carbon) – Focused Ion Beam thinning is also an option • MCL has a dual-platform FIB (FIB/SEM)
  30. 30. Materials Characterization Lab www.mri.psu.edu/mcl TEM Fees Instrument time: Philips EM420T: $30/hr JEOL JEM-2010: $35/hr JEOL JEM-2010F: $50/hr Staff time: $30/hr Training fee: $300 (Includes ~16 hours of instrument time with ~ 4 to 8 hours of personalized instruction as necessary) Consultation time to discuss your samples, data, etc is free.
  31. 31. Materials Characterization Lab www.mri.psu.edu/mcl Campus resources- coursework 1. Materials Science 531, Transmission electron microscopy, 3-credits: Overview of TEM, STEM and applications (Spring only) 2. Transmission electron microscopy, 1-credit lab course: Simple alignment of electron optical column, basic experiments in electron diffraction and imaging (Consult Course Schedule)
  32. 32. Materials Characterization Lab www.mri.psu.edu/mcl Campus resources- people 1. MCL (Joe Kulik, Jinguo Wang) 2. Elizabeth Dickey, Associate Professor of Materials Science & Engineering 3. Peter Heaney, Associate Professor of Geosciences 4. Arthur Motta, Professor of Nuclear Engineering 5. Theresa Mayer, Associate Professor of Electrical Engineering 6. Clive Randall, Professor of Materials Science & Engineering 7. Mary Beth Williams, Assistant Professor of Chemistry 8. Suzanne Mohney, Professor of Materials Science & Engineering Other resources: • www.mri.psu.edu/mcl/techniques/tem.asp (links, applications, etc) • MRI links to publications and abstract (Web of Science) searching (www.mri.psu.edu/linkspubs/) • Microscopy Society of America (MSA) (http://www.microscopy.org/)
  33. 33. Materials Characterization Lab www.mri.psu.edu/mcl www.mri.psu.edu/mcl Joe Kulik 194 MRI Bldg 865-0344 juk12@psu.edu