A feature scale transport and reaction model for atomic layer deposition

摘要

Interest in atomic layer deposition (ALD) has recently increased, particularly in the area of integrated circuit fabrication. This interest is due to its potential to deposit uniform films in high aspect ratio features. However, film nonuniformities have been observed in practice. To study potential sources of nonuniformities, we have developed a Boltzmann equation based transport and reaction model for ALD. The transport model has no adjustable parameters. Heterogeneous reaction mechanisms are used to express adsorption, desorption, and surface reaction steps. The parameters of these kinetic processes are those appropriate to a specific system, or can be chosen for demonstration purposes. In this paper, we focus on the adsorption of one species. The results for transient behavior of the number density and the surface coverage indicate that the experimentally observed nonuniformities may not be caused by the behavior of the adsorption step in ALD.