Molecular Dynamics Simulation of Defects in Ion Implanted and Annealed Silicon


Principal Investigator

James S. Williams

Research School of Physical Sciences and Engineering


Robert G. Elliman

C. Jagadish

Research School of Physical Sciences and Engineering

Dr Chris Goringe

EMU,University of Sydney


x03 -VPP

In order to obtain the desired electronic properties,
semiconducting materials such as silicon are
frequently modified by techniques such as ion implantation and neutron irradiation. This modification gives rise to large numbers of defects which, upon annealing, modify the property of the crystal. However, the atomic scale process by which such damage and annealing operate are not well understood, and it is the aim of the project to elucidate some of the specific details.


What are the results to date and the future of this work?

The behaviour of amorphous nanoclusters of silicon embedded in a crystal lattice have been studied. The shape of the cluster appears to play a vital role when the system is annealed, as local melting at high energy surfaces, edges and (in particular) corners leads to the amorphous phase rapidly converting to crystal. A small, roughly spherical amorphous regime remains despite long periods of annealing.

What computational techniques are used?

The tight binding approximation is used in a molecular dynamics simulation of 1000 atoms, over a period of 12ps. This implementation is the linear scaling density matrix method, as implemented by one of the investigators, and optimised for the VPP by Roger Brown.














- Appendix A