7. advanced SEM. Latest generation of SEM SEM

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Beverley Johnson
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1 7. advanced SEM SEM Low voltage SE imaging Condition of the surface, coatings, plasma cleaning Low voltage BSE imaging Polishing for BSE, EDX and EBSD, effect of ion beam etching/polishing 1 Latest generation of SEM Field emission gun monochromators beam boosters, beam deceleration, Lens-design: In-lens, Semi-inlens, immersion lens Short working distance Résolution (nm) Basse low voltage, tension/haute high resolution: résolution: - observation Observation de of la surface the real réelle surface - échantillons Non-metallic non-métallisés samples - faible Reduced endommagement beam damagedû au faisceau Haute High tension/haute voltage, résolution: - effets high de resolution: bord - détails Edge fins effects non-résolus FE - fort endommagement Charging effectsdû au faisceau Beam damage 1985 LaB 6 W Detectors: Everhard-Thornley (SE) In-column (through the lens, inlens, in-beam ) Low Voltage BSE detection, energy filtering (separation of materials and topography contrast) Tension d'accélération (kv) Analytical SEM: SDD EDX detectors (high throughput, large collection angle) High-speed EBSD detectors Beam currents of several 100 na 2

voltage, tension/haute high resolution: résolution: - observation Observation de of la surface the real réelle surface - échantillons Non-metallic non-métallisés samples - faible Reduced

2 SEM low kv imaging No specimen preparation needed: Low kv imaging of non-conducting, low density samples Al2O3 Nanocrystals FEI Magellan Operator: Ingo Gestmann Samples: Marco Cantoni 3 SEM low kv imaging No specimen preparation needed: Low kv imaging of non-conducting, low density samples Carbon nano-tubes (MWCT) FEI Magellan Operator: Ingo Gestmann Samples: Marco Cantoni 4

3 density samples Carbon nano-tubes (MWCT) FEI Magellan Operator: Ingo Gestmann Samples:

3 SEM low kv imaging No specimen preparation needed: Low kv imaging of non-conducting samples Liquid filled organic membranes Zeiss Nvision 40 Marco Cantoni 5 SEM low kv imaging No specimen preparation needed: Low kv imaging of non-conducting samples Liquid filled organic membranes Zeiss Nvision 40 Marco Cantoni 6

4 SEM low kv imaging Purely organic specimen: non-conductive, low density: Metal coating 15nm Ag/Pd coating 3nm Os coating HeLa Cells, Graham Knott Marco Cantoni, Nvision 40 7 SEM low kv imaging Easy sample: SC wire Nb 3 Sn in Cu matrix 8

coating 3nm Os coating HeLa Cells, Graham Knott Marco

5 SEM low kv imaging Easy samples: Everhard-Thornley detector (SE) Solid state BSE detector 9 SEM low kv BSE imaging 2keV, In-Column EsB detector Solid state BSE detector 10

6 SEM low kv imaging Easy samples: 11 SEM low kv imaging Easy samples: 12

7 SEM low kv imaging Easy samples: 13 SEM low kv imaging Contamination by hydro-carbons contamination spoils imaging at low kv How to avoid (at CIME): plasma cleaning of the sample before inserting Plasma clean the chamber at each insertion (multi-user environment) XL30 FEG & EVACTRON NVision40 & EVACTRON 14

plasma cleaning of the sample before inserting Plasma clean the chamber at

8 SEM: Preparation for analytical EM Nb 3 Sn multifilament superconducting cable 0.5 mm Nb 3 Sn superconductor multifilament cable: Nb 3 Sn filaments (diameter ~5um) in bronze matrix Solid State BSE detector 20kV acceleration voltage EDX maps Sn Cu Mechanical polishing <-> Ar ion beam polished Nb 15 Mechanical polishing: Grains of harder phase incorporated in softer matrix Deformed microstructure at surface reduces formation of Kikichi lines in EBSD SEM BSE/EDX/EBSD After Ar ion polishing (Gatan PIPS) Sn Cu Nb 16

detector 20kV acceleration voltage EDX maps Sn Cu Mechanical polishing <-> Ar ion beam polished Nb 15 Mechanical polishing: Grains

9 Ion polishing in-chamber ET-detector SE in-column InLens SE-detector in-column, energy-selective EsB BSE-detector 17 SEM low kv BSE imaging Nb 3 Sn multifilament Superconductors Materials & orientation contrast 5µm NVision kV EsB detector 18

10 FIB/SEM low kv BSE imaging Nb 3 Sn multifilament Superconductors Materials & orientation contrast 19 SEM preparation: polishing Goal of final polishing: Removal of the damaged surface layer mechano-chemical polishing (EBSD) or ion polishing 5kV 1kV 30kV escape depth of BSE: Nb 3 Sn 30kV: 800nm 5kV: 50nm 1kV: < 5nm Interaction volume Blue: scattered electrons Red: backscattered electrons (leaving the sample surface) Monte-Carlo Simulation CASINO v

(EBSD) or ion polishing 5kV 1kV 30kV escape depth of BSE: Nb 3 Sn 30kV: 800nm 5kV: 50nm 1kV: < 5nm Interaction

11 New HR-SEM at CIME Starting point: XL-30 SFEG SIRION (since 2001) First semi-in-lens HR-SEM: in-lens (through the lens) detection of SE and BSE Resolution in UHR mode: 1.5 nm at 10 kv (or higher); 2.5 nm at 1 kv 21 22

(through the lens) detection of SE and BSE Resolution

12 23 Best SEM at EPFL: FIB 24

13 Two different contrasts with one scan: parallel detectors 25 26

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16 31 MERLIN Introducing... Analytical power for the sub-nanometer world 32

17 MERLIN Analytical power for the sub-nanometer world High stability field emitter cathode Maximum probe current 300 na Beam Double Booster condenser lens Brightness Aperture independent of the electron probe probe current adjustment maintained for low landing energies Energy selective Backscatter detector (EsB) In-lens Secondary Electron detector GEMINI II final lens GEMINI II design Complete detection system Proven GEMINI final lens design New double condenser lens for highest probe current possibilities (300 na) Beam booster technology maintains brightness of all electron probes including low landing energies True on-axis in-lens SE and BSE detectors 33 34

Electron detector GEMINI II final lens GEMINI II design Complete detection system Proven GEMINI final lens design New double condenser lens for highest probe current

18 MERLIN Analytical power for the sub-nanometer world In-lens SE (Secondary Electron detector) Topographical information with on-axis in-lens SE detector system GEMINI II design Complete detection Complete detection system: Unique double in-lens detection Acquisition of pure secondary and backscatter electron signals Separation of compositional, topographical and crystalline surface information 35 MERLIN Analytical power for the sub-nanometer world Energy filtering grid EsB (Energy selective Backscatter detector) Compositional contrast with on-axis in column EsB detector Si 3 N 4 TiN Si Ti system GEMINI II design Complete detection Complete detection system: Unique double in-lens detection Acquisition of pure secondary and backscatter electron signals Separation of compositional, topographical and crystalline surface information 36

information 35 MERLIN Analytical power for the sub-nanometer world Energy filtering grid EsB (Energy selective Backscatter detector) Compositional contrast with on-axis in column EsB detector Si 3 N

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23 45 Sapphire 46

Electron Microscopy 3. SEM. Image formation, detection, resolution, signal to noise ratio, interaction volume, contrasts

Electron Microscopy 3. SEM. Image formation, detection, resolution, signal to noise ratio, interaction volume, contrasts Electron Microscopy 3. SEM Image formation, detection, resolution, signal to noise ratio, interaction volume, contrasts 3-1 SEM is easy! Just focus and shoot "Photo"!!! Please comment this picture... Any