Vapor Deposited Thin Films and Their Densification During Ion Beam Assisted Deposition

Abstract

ABSTRACTA computer simulation is presented of the reduction of void volume by incident energetic ions during Ion Beam Assisted Deposition (IBAD) of thin Ge films. The objective of the work is to understand the important mechanisms of thin film densification during IBAD. The density is affected by a number of mechanisms including: absorption of recoil atoms by voids and by diffusion of residual interstitials and vacancies. Simulations of Ge deposition under Ar ion bombardment were made using the collision cascade code MARLOWE with realistic void-sizes and for beam energies up to 500 eV. MARLOWE was used to obtain void volume loss as a function of void depth, void volume, and ion energy. The fate of residual interstitials and vacancies is taken into account.In order to model IBAD it is important to be able to model the deposition process. We describe our three-dimensional Molecular Dynamics simulations of the vapor deposition of Ni on a Ni (100) surface under low atom mobility conditions. We found the deposited film to have a packing density of about 80% of the nominal value and to contain ribbon-like voids.