Erosion of Ice Films by Energetic Ions

Author: Cooper, Barbara Hope

Year: 1982

Degree: Dissertation (Ph.D.)

Advisor: Tombrello, Thomas A.

Committee Members: Tombrello, Thomas A.; Frautschi, Steven C.; Burnett, Donald S.; Weinberg, William Henry

Option: Physics

DOI: 10.7907/yyye-qc47

Abstract

We measured the sputtering yields of ice films by 19F ions in the electronic stopping power energy regime. The yield was a function of the incident energy and charge state of the F beam, but did not vary for tar­get thicknesses ranging from about 30-70 x 1016H2O/cm2, or substrate tem­peratures from 10-60°K.

The energy dependence of the yield demonstrates that the sputtering mechanism is related to the electronic stopping power of the incident ion in the ice film. The detailed nature of this dependence is not understood. Predictions of thermal models and ion explosion models are compared to the experimental results.

Our F data on ice is compared to H and He sputtering of ice. We also review results from the literature where sputtering of other dielectric targets with ions in the electronic stopping power regime have been studied.

Possible connections with nuclear track formation in dielectrics and laser annealing are discussed. We also briefly mention the applications of enhanced sputtering of dielectrics; for example, in non-destructive desorption of large biomolecules and in astrophysical environments where frozen gas surf aces are bombarded by energetic ion fluxes.

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