The topology within recirculating flow in the atomic layer deposition thin film process

Nanotechnology fabrication has become a popular field inthe development of advanced and cutting-edge technologies.Deposition processes are industrialized to achieve nano-thinfilms with absolute control over the film thickness, conformaland uniform film growth over complex structures, and minimalto no defects or pinholes. Atomic layer deposition (ALD) hasrevealed itself as a possible candidate to achieve theserequirements. However, the in-depth understanding of thephysical and chemical formation of the thin film is stillunfamiliar to reactor designers, engineers and scientists. Forthe purposes of this study, the interest involves the mechanisticfactors of geometry influences, fluid flow, and masstransportation on the heterogeneous chemical reaction process.Through an industrial ALD process recipe, the transitional andrecirculation phenomena observed in the Atomic LayerDeposition (ALD) thin film process are seen to exert asignificant influence on the effective formation and growth ofthe thin film on the substrate. Topological fluid dynamics areused to analyze the two-dimensional numerical simulations ofthe backward-facing step (BFS) phenomena and therecirculation flow patterns typically found within a horizontalALD reactor. Focus is placed on investigating the saddle pointsin the resulting vortex shedding, eddy distortion andrecirculation due to the BFS phenomena. The topologicalanalysis is conducted for symmetrical step heights of 7.5mmand 10 mm respectively. Findings revealed close similarities toexperimental studies.