Berlin 2008 – scientific programme

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DS: Fachverband Dünne Schichten

DS 24: Trends in Ion Beam Technology: From the Fundamentals to the Application

DS 24.3: Invited Talk

Thursday, February 28, 2008, 10:30–11:00, H 2013

Cluster ion-surface interactions: from meV to MeV energies — •Kai Nordlund, Kristoffer Meinander, Tommi T. Järvi, Jarkko Peltola, and Juha Samela — Accelerator Laboratory, University of Helsinki, Finland

The nature of cluster ion-surface interactions changes dramatically with the kinetic energy of the incoming cluster species. In this talk I will review some of our recent work on the nature of cluster-surface interactions spanning an energy range from a few meV/cluster to about 1 MeV/cluster and cluster sizes in the range of 10 - 1000 atoms/cluster.

In the energy range of a few meV/cluster ion, the kinetic energy of the incoming ion is insignificant compared to the energy gained when the surface potential energy at the cluster-surface interface is released and partly translated into kinetic energy. Even in this energy regime I will show that surprisingly drastic effects can occur. When the energy of the incoming cluster is raised to a few eV/atom, the kinetic energy of the incoming cluster starts to affect the deposition. It will cause the cluster to entirely reform on impact. When the energy is raised to the range of keV's/cluster, the clusters start to penetrate the sample, fairly similar to conventional ion implantation. However, in dense targets the cluster ions may stick close to each other long enough to cause a significant enhancement of the heat spike in the material. Finally, I will show that at kinetic energies around 1 MeV/cluster the cluster enhancement of the heat spike may lead to dramatic surface effects.