Analysis of Layer Composition Formed on Stainless Steel Substrates upon Chemical Vapor Deposition of Tantalum

Abstract

This article discusses interaction between reagents and stainless steel substrate upon deposition of tantalum coating by reduction of tantalum bromide with cadmium. It has been established that, at deposition temperatures higher than 1000 K, iron and chromium in stainless steel will reduce tantalum pentabromide, transferring into the gas phase in the form of bromides. As a consequence, not only tantalum bromide is reduced on the substrate but also iron bromide, which leads to formation of sublayer containing iron in the coating. An increase in the surface area of stainless steel interacting with reagents leads to an increase in the content of iron bromide, and in this case, the coating is formed from the mixture of Ta + Fe2Ta. In addition, chromium bromide is formed on the substrate, which is removed together with other reaction products, resulting in depletion of chromium in steel surface layers.