Near-Threshold Sputtering and Ion Transport in Transition Metals

Understanding material loss due to ion interactions from a plasma is invaluable for a large array of applications. Whether they be desirable processes such as thin film coating technologies, for instance magnetron deposition; or undesirable processes, such as erosion of divertor walls in fusion reactors and grid damage in ion thrusters. The knowledge of the processes involved allows for better control over coating processes or predictability of material lifetime. The processes include effects such as sputtering and implantation, which depend on the energy of the incident particles (ions). At low energies, the process of sputtering is inefficient and not comprehensively understood – partly due to experimental challenges associated with generation of low energy ions and detection of loss– as they can be strongly material dependent.

This thesis is a step in the direction of understanding the various processes in ion-surface interactions and ascertain the efficiency of the sputtering process for materials commonly used in applications stated above. This is carried out by using a combination of experimental techniques and simulation methods to gain a more complete understanding of competition between sputtering and implantation at energies between 50 – 500 eV.