CFD Aids Chemical Vapor Deposition Uniformity
By Andy Banka, P.E. and Kevin Linfield, Ph.D., P.Eng., P.E.
Chemical vapor deposition (CVD) is a process in which chemical precursors flow through a heated vessel, where they react on the surface of a substrate to form a film. Gaseous by-products are carried away with the exiting flow. This process is used for a variety of products, including semiconductors, optical coatings, wear resistance coatings for cutting tools and other parts, coatings for chemical resistance, and advanced materials.
In order to generate films of uniform thickness, it is necessary to ensure that all portions of the substrate are exposed to equal amounts of the precursor gas. Failure to do so can result in uneven films and poor part performance.
ASC applied its computational fluid dynamics (CFD) tools to help aerospace company, Ultramet (Pacoima, CA) improve their CVD process. Ultramet specializes in the chemical vapor deposition of refractory metals, platinum group metals, and ceramics in the form of coatings, freestanding shapes, composites, and porous materials where high performance in extreme environments is required.
ASC's CFD simulations were used to assess Ultramet's CVD process and the effect of several system design parameters on the uniformity of precursor gas flow over the mandrel.
The simulation results provided Ultramet with insight regarding the process operation and helped to guide subsequent activities on this liquid rocket engine combustion chamber.
Airflow Sciences Corporation (ASC) is a fluid dynamics solutions company, specializing in the design and optimization of equipment and processes involving flow, heat transfer, combustion, and mass transfer. Now celebrating 50 years as an industry leader, ASC has focused on testing and simulation of air, gas, liquid, and particulate flows since 1975.
ASC also manufactures standard and custom test equipment, including probes and wind tunnels, enabling customers to collect data accurately and efficiently. ASC’s primary CFD software, Azore®, is also available for customers with in-house CFD personnel. ASC offers comprehensive flow solutions and optimization and serves a wide range of industries including HVAC, power, auto, rail, and food processing.