1 the microanalytical research centre david n. jamieson, and deborah r. beckman, jacinta den besten,...
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The Microanalytical Research Centre
David N. Jamieson,
and Deborah R. Beckman, Jacinta den Besten, Andrew A. Bettiol, Jamie S. Laird, Kin Kiong Lee, Steven Prawer
School of Physics, Microanalytical Research Centre, University of Melbourne, AUSTRALIA
Work supported by the Australian Research Council and the Visiting Fellowship Scheme of the University of Melbourne
http://www.ph.unimelb.edu.au/~dnj
SRC MeetingMicroanalytical Research CentreM A R C
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Facilities of the Centre
NEC 5U Pelletron accelerator with RIEF funded upgrade to make it one of the brightest accelerators in the world for nuclear microprobe operation ($2,000,000+)
Two MeV ion microprobe beam lines and associated instrumentation ($1,000,000 each)
Dilor confocal Raman spectrometer ($500,000) Joel UHV AFM ($700,000) Distributed computer network of one DEC Alpha workstation
and more than 20 satellite workstations and PC's ($100,000). Pulsed Laser Deposition System ($1,000,000) This combination of instruments is unique worldwide for one
research Centre!
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Atomic Force Microscope Image of Si 7 x 7 surface
reconstruction. Each dot is a single Si atom.
Lithography: Al Cimmino leaves his mark on a piece of Silicon. The width of the line is 2 nm and its depth is
0.2nm.
1nm 20 nm
ATOMIC RESOLUTION USING THE UHV ATOMIC FORCE MICROSCOPE
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MARC People
Academic Staff– Val Gurarie– David Jamieson– Michelle Livett – Steven Prawer
Postdoctoral Fellows– Jeff McCallum– Paul Spizzirri– +3
Infrastructure– Alberto Cimmino– Roland Szymanski– William Belcher– Eliecer Para
Students– Paul Otsuka– Matthew Norman– Elizabeth Trajkov– Brett Johnson– Amelia Liu– Leigh Morpheth– David Hoxley– Andrew Bettiol– Deborah Beckman– Jacinta Den Besten– Kristie Kerr– Louie Kostidis– Poo Fun Lai
– Jamie Laird– Kin Kiong Lee – Geoff Leech (part time RMIT)– Debora Lou-Greig– Ming Sheng Liu– Glenn Moloney– Julius Orwa– Arthur Sakalleiou– Russell Walker
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photons ions
ions
x-rays
nuclear fragments
ions
electrons
electrons
holes
Photons and MeV ions interact with matter
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keV electrons and MeV ions interact with matter
30 keV e 60 keV e
10 m
2 MeV He
5 m
0.5 m
•Deep probe•Large damage at end of range
• Restricted to 10 m depth, large straggling• Low beam damage
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Analysis modes
NRA: Nuclear reactions probe inner nucleus RBS: Rutherford Backscattering Spectrometry probes
nucleus PIXE: Particle induced x-ray emission probes inner
electron shells IBIC: Ion beam induced charge probes band gap IL: Ionoluminescence probes band gap
Dis
tanc
e of
pro
be io
n fr
om th
e nu
cleu
s Increasing energy of induced radiation
CLOSE
FAR
MeV
eV
Scattering process Name Application
X , X RBS Stoichiometry, Depth profiling
X , X-ray PIXE Trace elements (ppm)
X , e-h IBIC Electrical properties
X , h IL Valence
X , X´ NRA Light elements
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The Melbourne Pelletron Accelerator
Installed in 1975 for nuclear physics experiments.
National Electrostatics Corp. 5U Pelletron.
Now full time for nuclear microprobe operation.
Will be state-of-the-art following RIEFP upgrade
Inside
Outside
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Nuclear microprobe essential components
Aperture collimators
Beam steerer & Object collimators
Probe forming lens
Microscope
x-ray detector
SSBs
Ion pumps
Sample stage
goniometer
Low vibration mounting
From accelerator
1 m
Scanner
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Chamber inside
30 mm2 Si(Li) x-ray detector
25 and 100 msr PIPS particle detectors at 150o
75 msr annular detector
Re-entrant microscopeport & light
SiLi port
Specimen
SSB detectors
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MARC activities 1995 - 1999
IBMM: Ion Beam Modification of Material, IBA: Ion Beam Analysis
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PIXE: Transitions following ionization
1: Knock out electron from K-shell (ionization) 2: Decay from L or M shell produces K x-rays
G. Moseley discovered this in 1910 From elementary quantum mechanics, the K x-ray energy is given by:
EK = (ke2/2a0). (3/4)(Z-1)2 (Hydrogenic n=2 to n=1 transition)
a0 = Bohr radius, k = Coulomb constant, e = electron charge
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PIXE: Au loaded Mineral - Pyrite (FeS2)
Specimen from Emperor Au mine in Fiji
Called Fool’s gold in Australia
Also find much gold in this mineral in Australia
How did the Au get into the mineral?
The work of Jacinta den Besten
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PIXE: Mapping Pyrite crystal from windows in energy spectrum
Crystals grow from melt by heteroepitaxy under geological conditions
Elemental zoning can be mapped with 3 MeV proton induced x-ray emission
Au appears incorporated into crystals as: Au metal lumps Lattice substituted
uniform distribution
500x500 m2 scan size
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Rotation
2-D scanParticle Detector
Sample
4.5 MeV 3-D tomography of 40 m catalyst particle
X-ray Detector
The work of Arthur Sakellariou
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RBS: Rutherford Backscattering Spectrometry
Lots of recoil
Light nucleus
Low energy Useful for
measuring light elementsHeavy
nucleusLittle recoil
High energy
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NRA: Nuclear Reaction Analysis
Light nucleus
Very high energy
BEFORE
AFTER
Useful for measuring lightest elements
Transmutednucleus
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RBS: 2 MeV He+ depth profiling of IR photodetectors
Pd
100 m
Metal(Au)
HgCdTe
Detector
2 MeV He+
GaAs
HgCdTe
Au
Pd
GaAs
MCT
Au
Pd
Non-destructive RBS tomographic image
Photo
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GaN is a novel wide band-gap semiconductor with many desirable properties
Single crystal films are required for microelectronic device applications
Epitaxial growth of GaN on sapphire is possible, but displays growth defects
CCM image shows excellent crystallinitychi-min<3%, t=0.53m
Example: CCM analysis of epitaxial GaN films
50m (a)
50m
(b)
2.5 MeV He+, 200 m scan
The work of Deborah Beckman
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2.3 MeV protons on PMMA This work dates from 1996, much more interesting structures are
now available See review by Prof F. Watt, ICNMTA6 - Cape Town, October
1998
The work of Frank Watt
Micromachining in PMMA at the National University of Singapore
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MeV ions interact with matter
PMMA substrate(side view)
100 m
surface
3 MeV H+ MeV ions penetrate
deeply without scattering except at end of range.
Energy loss is first by electronic stopping
Then nuclear interactions at end of range
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Micomachining
Example Proton beam lithography
– PolyMethyl MethAcrylate (PMMA)– exposure followed by development– 2 MeV protons– clearly shows lateral straggling
Protons
Side view
10 m
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Single ion tracks
Latent damage from single-ion irradiation of a crystal(230 MeV Au into Bi2Sr2CaCuOx)
Lighter ions produce narrower tracks!
(Huang and Sasaki, “Influence of ion velocity on damage efficiency in the single ion target irradiation system” Au-Bi2Sr2CaCu2Ox Phys Rev B 59, p3862)
1 m
3 m
5 m
7.5 m
Depth
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Self Assembled Monolayers for nanofabrication
Monolayer deposition
Contact formation
AFM images of end-groups
Credits:A: www.ifm.liu.se/Applphys/ftir/sams.htmlB-D: IBM Research Labs www.zurich.ibm.com/~bmi/sams.html
A
B
C
D
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MeV ion etch pits in track detector
Heavy ion etch pit
Single MeV heavy ions are used to produce latent damage in plastic
Etching in NaOH develops this damage to produce pores
Light ions produce smaller pores
1. Irradiate 2. Latent damage
3. Etch
From: B.E. Fischer, Nucl. Instr. Meth. B54 (1991) 401.
Scale bars: 1 m intervals
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Resist layer
Si substrate
MeV 31P implantEtch latent damage
& metallise
Read-out state of “qubits”
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Device fabrication:Layered waveguides
Ion energy ---- waveguide depth
The work of Mark von Bibra
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Optical Materials
Fused Silica– Increase in density at end of range – Increase in refractive index (up to 2%) at end of range
Proton beam
Enhanced index region
Substrate
silica surface
2 MeV H+
20m
laser light emerging
The work of Mark von Bibra
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Device fabrication: Other passive devices
Waveguide couplers
The work of Mark von Bibra
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Device fabrication: Y junctions
Waveguide splitters Composite image (with enhancement)
Waveguide Couplers
The work of Mark von Bibra
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References
Materials Analysis using a Nuclear Microprobe– Breese, Jamieson and King
– John Wiley & Sons, New York 1996
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Microanalytical Research Centre Commercial OrganisationM A R C ONuclear Microprobe Laboratories
Made in Melbourne Other microprobes (1999)
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Conclusions
Structural characterisation:– Spatial resolution of for conventional IBA 0.4 m– Elemental sensitivity with PIXE 10 ppm – Depth resolution with RBS 50 nm – Lattice location studies with ion channeling
Electrical characterisation– Spatial resolution for IBIC 0.1 m– Mapping of charge trapping an recombination centres
Sub-trace optically active colour centres with luminescence 3D density and elemental mapping with tomography Stay tuned for further developments......
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