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CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
The Melbourne Node
Microanalytical Research CentreM A R C
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
The Melbourne Node
Test structures created by single ion implantation
Atom Lithography and AFM
measurement of test structures
Theory of Coherence and Decoherence
Node Manager: Steven Prawer
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
Test structures created by single ion implantation
Node Team Leader: Steven
Prawer
Atom Lithography and AFM
measurement of test structures
Theory of Coherence and Decoherence
The Melbourne Node
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
• Students– Paul Otsuka– MatthewNorman– 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
Key Personnel
• Academic Staff– David Jamieson– Steven Prawer– Lloyd Hollenberg
• Postdoctoral Fellows– Jeff McCallum – Paul Spizzirri– Igor Adrienko – +2
• Infrastructure– Alberto Cimmino– Roland Szymanski– William Belcher– Eliecer Para
– Geoff Leech* DeborahLouGreig
– Ming Sheng Liu– Glenn Moloney– Julius Orwa– Arthur Sakalleiou– Russell Walker
– Cameron Wellard*
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
Existing Infrastructure
• 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 ($100,000).
• Pulsed Laser Deposition System ($1,000,000)
• This combination of instruments is unique worldwide for one research Centre!
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
The Science
• Creation of an array of phosphorous ions ina Si m
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
Accelerator
Specimen Chamber
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
• Capable of delivering a single ion into an area 0.25 mm in diameter
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
JEOL Variable Temperature UHV AFM/STM
• Imaging RT-800K
• Cantilever based AFM
• STM imaging with tip or AFM cantilever
• All imaging modes available
• In situ evaporation source.
• In situ ion sputtering.
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
Si (111) 2 x 1 surface obtained by cleavage in
UHV
from Haneman and Adrienko
Au deposited in-situ on
Si (111) surface
2 x 1 reconstruction
Atom Lithography: Key Imaging & Fabrication Technology
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
100 x 100 nm
20 nm
Alberto Cimmino leaves his mark
1 atom deep, 10 atoms wide
Programmed Lithography for nanofabrication
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
AFM imaging of surfaces:
Atomic Force Microscope Image of Si 7 x 7 surface reconstruction. Each dot is a single Si atom.
1nm
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
Test structures created by single ion implantation
• The basic idea • Previous work• Potential problems and solutions
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
Single Ion Implantation Fabrication Strategy
Resist layer
Si substrate
MeV 31P implant Etch latent damage&
metallise
Read-out state of “qubits”
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
MeV ion etch pits in track detector
• Single MeV heavy ions are used to produce latent damage in plastic
• Etching in NaOH develops this damage to produce pits
• Light ions produce smaller pits
1. Irradiate 2. Latent damage
3. Etch
From: B.E. Fischer, Nucl. Instr. Meth. B54 (1991) 401.
Scale bars: 1 m intervals
Heavy ion etch pit
Light ion etch pits
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
From 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
Single ion tracks
• Latent damage from single-ion irradiation of a crystal (Bi2Sr2CaCuOx)
• Beam: 230 MeV Au
• Lighter ions produce
narrower tracks!
3 nm
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
Project Management - A distributed system
Director Clark
Deputy Director Milburn
Theory/Modelling Array fabricationReadout
SET Dzurak
Magnetic Resonance
(LANL)
Quantum Optics
Rubeinstein-Dunlop
Single Ion Implantation
Jamieson
Atom Lithography
Prawer
Silicon MBE
Simmons
CENTRE FOR QUANTUM COMPUTER TECHNOLOGY
Potential Problems
Problem Solution
Single ion resist exposure Try cross linking SAMS
Lateral straggling ofimplanted ions
Optimize surface layers and ion energy
Residual damage Optimize implantation temperatureand post implantation annealing