Nano Analytical Electron Microscopyfor

Materials and Semiconductor Applications

W. Knoll

Autumn School on Materials Science and Electron Microscopy 2005

State of the Art2200FSat Oxford Materials, University of Oxfordthat has an in-column energy filter,double Cs correctorsand will be equipped with a Monochromator

2200FS Height requirement; 3110 mm

A Cs corrector height is 300 mmMonochromated 2200FS increases its heightby 400mmTotal increase in height is 1000 mm forMonochromated x Cs 2200FS.

Analytical Probe sizes less than 0.1nmTEM resolution 0.08nm or betterHolographic reconstructions less than 0.1nmFEG: cold/thermal/SchottkyEnergy resolution in EELS less than 20meV - more typical values less than 100meV - routine values of 700 – 800meV - Monochromators helpEDS resolution less than 1 eV (1000meV)CCD Camera images 4K x 4K (8K under development at UCSD) Contemporary computer control - contemporary means TODAY

Current state-of-the-art instrument capability

Directions for the future• Computer control• Automation• Vacuum• In-situ capabilities• Reconstruction software• Remote control• Resolution

– Energy resolution– Spatial resolution

1 - Outline

2 Elimination of specimen contaminationSpecimen size Portion of contaminant

3 Long time analysisSpecimen size Signal from the specimen

Investigating nanoscale needs improved instruments

1 Preparation of specimen Specimen size Portion of damaged surface

2 - Matching environmental conditions

Improved HT and lens current Stability

Stability Goniometer Design

Improved vibration isolation

Improved acoustic resonance behavior

3 - Resulting Performance

HAADF image of Si (110) by JEM-2100F/STEM

Original image Inverse FFT image

0.5nmFFT

400 spot

InverseFFT (after Masking)

SA-Diff

HR-TEM image of Si(110) Dumbbell by JEM-2100F

0.136 nm

TEM Study of Water in Carbon Nanotubes

TEM images of MWNT containing a water plugUpon e-beam heating, the plug shrank from (a) to © and disappeared in (d)The position of water, gas and water menisci are indicated in (a)A carbon internal cap is also indicated - apparently leaking and not blocking water motion

Large diameterMWNT

TEM Study of Water in Carbon Nanotubes

(a) TEM image showing an empty CVD nanotube with inner diameter of 2.9 nm(b) After autoclave treatment water is observed in the NT-channels

- but it does not show a meniscus at the water/gas interface

Small diameterMWNT

SemiconductorSTEM-Tomography

4 Applications to Ultrastructre

DRAM STEM SEM Image

Tilting angle: -60° to +44° 4°stepJEM-2500SE + JEM-9310FIB used

3D reconstructed series of SEM images

5 - Energy Filtered Microscopy

JEOL In-Column Filter TEMs- Application: Imaging -

Remove Plasmon Loss Electrons → Intensity is decreased, but image quality is enhanced

Specimen:Si[110]

Zero Loss Imaging

SpectrumSpectrum

CrossoverCrossover

(Energy Slit)(Energy Slit)

IL1IL1IL2IL2IL3IL3IL4IL4

PL1PL1PL2PL2

ImageImage

ImageImage

Un-filtered

0-loss filtered

Image quality improvement of 1 mm thick sectioned specimen

0 100 200 300Energy Loss (eV)

Inte

nsity

(Arb

. Uni

t) δE ~20eV

Zero

loss

2um thickness

non-tilted specimen

Most Probable Loss (MPL) Imaging

-1 0 1G

Inte

nsity

(Arb

. Uni

t) UnFiltered

-1 0 1G

Inte

nsity

(Arb

. Uni

t) Zero-Loss Filtered

UnFiltereddiffraction

Zero-loss diffraction

Specimen: NiMo alloy

Diffraction Pattern Contrast Enhancement

Unfiltered Zero Loss filtered

Maximum takeoff angle 120 mrad

CBED Patterns from Si <111>

JEOL In-Column Filter TEMs- Application: Spectroscopy -

B-K C-KSampling resolution 0.0125 eV/pixel

Wide range of spectrum magnification change

JEM-2200FS

EELS and HR-TEM Images of Carbon Allotropes

Amorphous

Diamond

5 nm

5 nm

5 nm

Plasmon loss C-K TEM image

Carbon Black

Graphite

Diamond

JEM-2200FS

JEOL In-Column Filter TEMs- Application: Energy Filtered Imaging -

Contrast tuning of trench capacitor

JEM-2200FS

Energy-loss Spectra of Polyolefin/Polycarbonate Blend

Polyolefin Polycarbonate

s-Plasmon s-Plasmonp-Plasmon

JEM-2200FS

1 µm

Energy Filtered Images of Polyolefin/Polycarbonate Blend

Unfiltered p-Plasmon Filtered

JEM-2200FS

Collection angle: 0.28 sr

6 - High Efficiency EDS Collection

No X-ray background contribution from HCA

Al O

Ti C

F

300 nm

HAADFMemory head

EDS Mapping

Clean X-ray background (better S/N) facilitates quantitative mapping. Need better S/N for statistics? Use line scan.

Spatial drift-corrected mapping

As doping: 25 keV, 5e15/cm2

No annealing process256x256, x 300.000, 60 min

Si

O

AsMix

STEM

EDS

100 nm

(a) Z-contrast

(b) Ag map 10 min (c) Cu map 10 min

(b’) Ag map 60 min (c’) Cu map 60 min

4 nm

Incident beam // <110>matrix

Drift Corrected High-Resolution EDS Mapping of Plate like Precipitate in Al alloy

Time Difference

(a) Z-contrast

Cs correctors, in addition to improving resolution, offer other significant improvements and benefits. In STEM:

Wider gap – More room…larger tilt, in-situ experiments

Tilt insensitivity – coma is eliminated when Cs disappears. Tilt tableaus are therefore commonly used to align the corrector in the STEM mode

Interpretable images – less image delocalization (at interfaces, for example), familiar contrast

More current – At least 10X improvement…mapping, EELS, small probe analysis

7 - Cs Correctors

Sub Å EELS3 Å EDSLive ADF imaging

Probe size vs. current

JEM-2200FS

STEM Cs corrector

(Probe forming)

CLCMOL

IL

PL

Ω filter

CL

OLCM

IL

Ω filter

PL

CEOS GmbH

STEM Corrector Lens System

11mrad (alpha) 40mrad (alpha)

Cs corrector off Cs corrector on

Ronchigram

-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5

nm

FWHM0.105 nm

Cs=0.005mm

Corrected

STEM Cs Corrector

(226)0.082nm

(006)0.0905nm (224)

0.11nm

(440)0.096nm

Cs Corrected HRSTEM image of Si(110)

SrTiO3 <100>

Specimen courtesy of John Grazul, Cornell Univ.M. Kanno, R. Hynes, H. Sawada and M. Watanabe, Lehigh Univ.

2 nm

β-Si34

Calculatedpotential

STEM Cs Corrector

2 nm

HAADF of Alumina with tri-rhenium carbonyl clusters deposited

V. A. Bhirud, M. J. Moses, D. A. Blom, L. F. Allard, T. Aoki, S. Mishina, C. K. Narula, and B. C. GatesM&M Proc. 2005, Submitted

Tri-rhenium carbonyl clusters on γ-alumina

Final ADF image

Tri-rhenium carbonyl clusters on γ-alumina

V. A. Bhirud, M. J. Moses, D. A. Blom, L. F. Allard, T. Aoki, S. Mishina, C. K. Narula, and B. C. GatesM&M Proc. 2005, Submitted

e- e-

V. A. Bhirud, M. J. Moses, D. A. Blom, L. F. Allard, T. Aoki, S. Mishina, C. K. Narula, and B. C. GatesM&M Proc. 2005, Submitted

Tri-rhenium carbonyl clusters on γ-alumina

Er in SiC

Data courtesy to Drs. D. Muller and U. Kaiser

Er-M lines

Single atomic column detection