A modified lattice potential model of electronically mediated sputtering

Abstract

We develop a new, quantitative model describing the electronically mediated erosion of dielectric materials by fast ion bombardment. This model is based on the concept that the effective inter-molecular lattice potential is transiently but significantly modified in some restricted region about the primary ion path, due to intense electronic excitation. The acceleration of the nuclei in this modified lattice potential transfers appreciable energy to molecular motion. Sputtering yields are calculated without the introduction of adjustable parameters or arbitrary normalization, and the results compare favorably with the available data. Sputtering induced by both heavy and light ions, on both refractory dielectric materials and condensed volatiles may be treated. The model calculations are consistent with observed yields ranging over three orders of magnitude. There are possible applications of the model to related radiation effects, including track registration and the soft failure of solid state computer devices.