A new continuum model of thin film deposition incorporating finite atomic length scales

We have investigated a limitation of the standard continuum model of thin film deposition which manifests itself under conditions of glancing incidence over sharp-cornered features. By comparing numerical simulations of both the continuum model and an atomistic model with experiments on long-throw sputter deposition of Ta we have elucidated this limitation of the continuum model. We have therefore developed a new continuum model which incorporates finite atomic length scales. The model incorporates effects of atomic interactions, which lead to the capture of impinging atoms that pass near a point on the film. This capture effects results in "breadloafing" at sharp convex corners where the curvature is high. We have validated this new model in idealized two dimensional simulations and obtained improved qualitative agreement with both experiment and Monte Carlo atomistic simulations. Finally, we have also developed and implemented a more general three dimensional model which successfully results in the breadloafing effect.