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