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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......