Annual Report 2009.pdf - School of Physics - University of Melbourne

group reports & publicationsmicro-analytical research centre (MARC)dr jeff m c callumThe Microanalytical Research Centre (MARC)undertakes research in the areas of advancedmaterials and device fabrication and characterization.The research effort of the MARC group ispredominantly in the areas of silicon and diamondmaterials and device development, with a strongemphasis on ion beam processing and ion beamanalysis.An activity of key importance in the MARC groupis the experimental program of the Melbournenode of the Australian Research Council Centreof Excellence for Quantum Computer Technology(CQCT). The CQCT is internationally recognized forits groundbreaking research into quantum devicedevelopment and measurement. The Melbournenode of CQCT is headed by Prof. Lloyd Hollenbergwho also leads the Centre’s theoretical program. Theexperimental programs at Melbourne are centredon our expertise in single ion implantation, lead byProf. David Jamieson, for single atom quantum bit(qubit) formation and materials characterization anddevelopment, lead by Dr Jeff McCallum. There isvery strong collaboration between researchers at theMelbourne node and researchers at the other majornodes, particularly the team at the University of NewSouth Wales (UNSW).Prof. Jamieson also leads the Melbournecontribution to the Atomic Functionalities in SiliconDevices (AFSiD) project that is funded through theEuropean Union Seventh Framework.The diamond group within MARC is lead by Prof.Steven Prawer. This group has a strong internationalreputation in the field of diamond-based quantumoptics and quantum computing and is part of theconsortium that at the end of 2009 was awarded$42M funding to develop the bionic eye. This is amajor and prestigious initiative which will conductan ambitious program of research over the next fouryears and will bring a number of new post-doctoralfellows and research endeavours to the group. TheMARC group also has strong research linkages withthe Australian National University, Royal MelbourneInstitute of Technology and other research groupsworldwide.The CQCT’s quantum device (Ion Beam) programat the University of Melbourne collaborates closelywith the quantum device program at the Universityof New South Wales on the fabrication of Si:Pdevices containing single or few dopant atomsby top-down methods. Over the past decadethe group has perfected an integrated method ofcounting single atoms into silicon devices that isnow commonly referred to as deterministic doping.In 2009 a number of the Si:P devices showedextremely interesting characteristics based on thetransfer of single electrons between a gate-definedquantum dot structure and a small number ofphosphorus donors implanted nearby. This researchis detailed in the CQCT Annual Report. A highlightof 2009 was the invitation to present our work at aninterdisciplinary workshop “Atomics09” in Germanywith delegates working on different strategies forthe exploitation of the quantum attributes of singleatoms. The group has also worked on developinga step-and-repeat system that incorporates ouron-chip single ion detectors and employs a scannednano-scale aperture that collimates the ion beam toless than 100 nm. This system will, when it is fullyfunctional, provide precise control over the locationof our single ion implants. The nano-scale aperturesare fabricated by focused ion beam milling of Sicantilevers and SiN membranes and use SEM andTEM imaging to characterise the milling process.In 2010 the system will be used to demonstratecontrolled implantation of low energy single ions.The CQCT’s Materials Program at the Universityof Melbourne has developed and utilizes a numberof defect characterization techniques in order toinform the Centre on optimal processing strategiesand defect control in its device structures. In 2009,the fixed oxide charge and the Al-Si work-functiondifference were measured for the gate structuresused in the Centre devices. The group is also movingtowards measurement of spin-dependent transportin electrically detected magnetic resonance (EDMR)devices completely fabricated with ion implantationtechniques. This is another important collaborationwith colleagues at UNSW. A temperaturedependentHall measurement capability was alsoadded to the group’s characterization suite this year.The system will allow measurement of carrier-type,concentration and mobility over the temperaturerange 20 - 320 K. The Hall system is also equippedwith a 1 Tesla electro-magnet.www.physics.unimelb.edu.au 35