Electronic interactions of medium-energy ions in hafnium dioxide
2014 (English)In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 89, no 3, 032711- p.Article in journal (Refereed) Published
In this article, the electronic interaction of medium-energy ions with hafnium dioxide is studied. Stopping cross sections for He ions in the energy range from 30 to 160 keV have been measured in backscattering experiments from thin films of HfO2 on Si using time-of-flight medium-energy ion scattering. The observed energy loss for helium ions is found to be high compared to expectations from earlier results for hydrogen in HfO2, a result which indicates a contribution from energy-loss processes that is different from direct excitation of electron-hole pairs in close collisions. Furthermore, data exhibit a significant deviation from velocity proportionality. A discussion of the results, together with data from studies for H and He in SiO2, show characteristic differences which are traced back to different electronic structures of the target materials and their influence on the charge-exchange channels that are active in the interaction with helium. Charge exchange, in turn, via shifted mean-charge states, will influence the observed ionization along the ion track. The results can furthermore serve as reference values for ion-beam-based depth profiling at medium and low ion energies.
Place, publisher, year, edition, pages
2014. Vol. 89, no 3, 032711- p.
IdentifiersURN: urn:nbn:se:uu:diva-223889DOI: 10.1103/PhysRevA.89.032711ISI: 000333188200007OAI: oai:DiVA.org:uu-223889DiVA: diva2:715575