7. advanced SEM. Latest generation of SEM SEM

MSE-602 2013 advanced SEM

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

100 50

10 5

1 0.5 1 2 5 10 20 30

FE

LaB

W

Tension d'accélération (kV)

Résolution (nm)

Basse tension/haute résolution:

- observation de la surface réelle - échantillons non-métallisés - faible endommagement dû au faisceau

Haute tension/haute résolution:

- effets de bord - détails fins non-résolus - fort endommagement dû au faisceau

1985

2010 Field emission gun

monochromators beam boosters, beam deceleration,

Lens-design: In-lens, Semi-in- lens, immersion lens

Short working distance

Detectors:

Everhard-Thornley (SE)

In-column (through the lens, in- lens, “in-beam”)

Low Voltage BSE detection, energy filtering (separation of materials and topography contrast)

Analytical SEM:

SDD EDX detectors (high throughput, large collection angle)

High-speed EBSD detectors

Latest generation of SEM

High voltage, high resolution:

• Edge effects

• Charging effects

• Beam damage

low voltage, high resolution:

• Observation of the “real” surface

• Non-metallic samples

• Reduced beam damage

MSE-602 2013 advanced SEM

SEM low kV imaging

No specimen preparation needed:

Low kV imaging of non-conducting, low density samples

FEI Magellan

Operator: Ingo Gestmann Samples: Marco Cantoni

Al2O3 Nano- crystals

3

SEM low kV imaging

No specimen preparation needed:

Low kV imaging of non-conducting, low density samples

FEI Magellan

Operator: Ingo Gestmann Samples: Marco Cantoni

Carbon nano-tubes

(MWCT)

MSE-602 2013 advanced SEM

SEM low kV imaging

No specimen preparation needed:

Low kV imaging of non-conducting samples

Liquid filled

organic membranes

Zeiss Nvision 40 Marco Cantoni

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SEM low kV imaging

No specimen preparation needed:

Low kV imaging of non-conducting samples

Liquid filled

organic membranes

Zeiss Nvision 40

MSE-602 2013 advanced SEM

SEM low kV imaging

Purely organic specimen: non-conductive, low density:

Metal coating

HeLa Cells, Graham Knott Marco Cantoni, Nvision 40

15nm Ag/Pd coating

3nm Os coating 3nm Os coating

7

SEM low kV imaging

“Easy” sample:

SC wire

Nb ₃ Sn in

Cu matrix

MSE-602 2013 advanced SEM

SEM low kV imaging

“Easy” samples: Everhard-Thornley

detector (SE)

Solid state BSE detector

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SEM low kV BSE imaging

Solid state BSE detector

2keV, In-Column

EsB detector

MSE-602 2013 advanced SEM

SEM low kV imaging “Easy” samples:

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SEM low kV imaging “Easy” samples:

MSE-602 2013 advanced SEM

SEM low kV imaging “Easy” samples:

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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

SEM low kV imaging

MSE-602 2013 advanced SEM

0.5 mm

Nb ₃ Sn multifilament superconducting cable

Nb

Sn superconductor multifilament cable:

14’000 Nb

Sn filaments (diameter ~5um) in bronze matrix SEM: Preparation for analytical EM

Solid State BSE detector 20kV acceleration voltage

Mechanical polishing <-> Ar ion beam polished

EDX maps Sn

Cu

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

MSE-602 2013 advanced SEM

in-chamber ET-detector SE

in-column

“InLens”

SE-detector

in-column, “energy-selective” EsB BSE-detector

Ion polishing

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Nb

Sn multifilament Superconductors Materials & orientation contrast

SEM low kV BSE imaging

NVision 40

1.8kV EsB detector

5µm

MSE-602 2013 advanced SEM

Nb

Sn multifilament Superconductors Materials & orientation contrast

FIB/SEM low kV BSE imaging

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Goal of final polishing:

Removal of the damaged surface layer

mechano-chemical polishing (EBSD) or ion polishing

Interaction volume

Blue: scattered electrons Red: backscattered electrons

(leaving the sample surface) Monte-Carlo Simulation CASINO v2.42 escape depth of BSE: Nb

Sn 30kV: 800nm

5kV: 50nm

1kV: < 5nm

SEM preparation: polishing

1kV 5kV

30kV

MSE-602 2013 advanced SEM

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

MSE-602 2013 advanced SEM

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Best “SEM” at EPFL: FIB

Nvision@CIME

MSE-602 2013 advanced SEM

Two different contrasts with one scan: parallel detectors

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MSE-602 2013 advanced SEM

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MSE-602 2013 advanced SEM

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MSE-602 2013 advanced SEM

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Introducing...

MERLIN™

– Analytical power for the sub-nanometer world –

MSE-602 2013 advanced SEM

 Double condenser lens

 Aperture independent probe current adjustment

 Beam Booster

 Brightness of the electron probe maintained for low landing energies

MERLIN™

– Analytical power for the sub-nanometer world –

 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

► GEMINI

II design Complete detection system

 High stability field emitter cathode

 Maximum probe current 300 nA

 Energy selective Backscatter detector (EsB)

 In-lens Secondary Electron detector

 GEMINI

II final lens

33

MSE-602 2013 advanced SEM

In-lens SE

(Secondary Electron detector)

Topographical information with on-axis in-lens SE detector

MERLIN™

– Analytical power for the sub-nanometer world –

GEMINI

II design

► Complete detection system

Complete detection system:

 Unique double in-lens detection

 Acquisition of pure secondary and backscatter electron signals

 Separation of compositional, topographical and crystalline surface information

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EsB

(Energy selective Backscatter detector) Energy filtering

grid

Si

Si

N

TiN Ti

Compositional contrast with on-axis in column EsB detector

MERLIN™

– Analytical power for the sub-nanometer world –

Complete detection system:

 Unique double in-lens detection

 Acquisition of pure secondary and backscatter electron signals

 Separation of compositional, topographical and crystalline surface information

GEMINI

II design

► Complete detection

system

MSE-602 2013 advanced SEM

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MSE-602 2013 advanced SEM

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MSE-602 2013 advanced SEM

41

MSE-602 2013 advanced SEM

43

MSE-602 2013 advanced SEM

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Sapphire