ATOMIC SCALE FABRICATION AND CRYSTAL GROWTH


Program Manager:
Prof Michelle Simmons - University of New South Wales

Participating University of New South Wales Node Researchers:
Dr Thilo Reusch Dr Giordano Scappucci Dr Frank Ruess

Technical Manager:
Mr Jeremy Chu

Students:
Mr Daniel Thompson (PhD) Mr Martin Füchsle (PhD) Mr Wilson Pok (PhD) Ms Sarah McKibbon (PhD)	Mr Huw Campbell (PhD) Mr Craig Polley (PhD) Mr Bent Weber (Masters)
Collaborating Centre Researchers:
University of New South Wales:	Los Alamos National Laboratory, USA:
Dr Warrick Clarke Dr Xiaojing Zhou Dr Andreas Fuhrer A/Prof Alex Hamilton Dr Adam Micolich Mr Fulvio Ratto (PhD)	Dr Marilyn Hawley Dr Geoff Brown Dr Holger Grube
University of Newcastle:	University of Sydney:
Prof Philip Smith Dr Marian Radny Dr Steven Schofield	Prof David McKenzie Dr Nigel Marks Dr Oliver Warschkow
University of Melbourne:
A/Prof Lloyd Hollenberg Prof G. Klimeck (Purdue)

Program Description:

Within the Atomic Fabrication and Crystal Growth Program we have developed a unique nano to atomic-scale device fabrication strategy in silicon to manipulate and incorporate dopants at the atomic level using a combination of scanning probe microscopy and molecular beam epitaxy. By adapting scanning probe systems and combining them with crystal growth systems we have moved the STM away from just an imaging tool, to a device patterning and fabrication tool. Significantly we have developed a method to reliably make four terminal electrical contact to devices patterned using the atomic precision of the STM once they are removed from the ultra-high vacuum microscope environment. In addition we can image each stage of the fabrication process. In this way we are able to measure the electrical characteristics of STM-patterned devices at cryogenic temperatures and in high magnetic fields, allowing us to correlate electronic device characteristics directly with dopant placement and number.

We use this technology to develop device architectures down to the atomic-level with the long term goal of realising atomically precise, scalable qubits in silicon. Central to this goal is the need to understand how to identify single dopants in silicon, how to determine their location during each stage of the fabrication process, how to characterise the electrical environment of the dopants and then how to control charge and spin transfer between dopants. Each of these fields represents a formidable challenge.

	Nano to atomic-scale silicon wires In the nanowire team we are trying to understand what limits electrical conduction in doped silicon nanowires towards the goal of making an atomically precise wire.
	Identification and manipulation of single dopants in silicon We have an extensive program investigating the surface chemistry and incorporation of P as the dopant using phosphine gas as the dopant source. Using STM-based hydrogen resist lithography we pattern P dopants in silicon with atomic precision.
	2D electron transport We investigate the nature of phase coherent 2D electron transport in P-doped silicon. Recent work concentrates on the ability to create ordered dopant arrays in silicon.
	Electron spin and charge qubits in quantum dots We are starting to investigate the coherent properties of electron spin and charge in single and coupled quantum dots with the goal of realizing prototype architectures for a solid state quantum computer.
	Atomic-scale device fabrication strategy We have developed a unique strategy to pattern planar dopants in silicon with the atomic-precision of the STM. We are now enhancing this technology to incorporate low temperature silicon dioxide growth so that we may align surface gates to buried STM-patterned dopants.

Publications

Employment Opportunities

Alumni
Dr Jeremy O’Brien (PhD) Dr Steven Schofield PhD) Dr Johnson Goh (PhD) Dr Toby Hallam (PhD) Dr Lars Oberbeck (Post-doc) Dr Neil Curson (Post-doc) Mr Andrew Sunderland (Honours)	Mr Justin Armellin (Honours) Mr Nick Bell (Honours) Mr Peter Priestly (Honours) Ms Nadia Lo (Honours) Ms Yael Augarten (Honours) Ms Lisa Caldalano (Honours) Ms Angela Langdon (Honours)

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