Influence of solute segregation on stress and structure evolution in nanocrystalline thin films

Alloy thin films offer several tantalizing opportunities to engineer the growth and subsequent stress conditions in thin films. This can be achieved by the mixed interaction of two or more species. For example, grain size is a known quantity in regulating the stress and is most often controlled through processing via pressure, temperature, deposition rate, or a combination of each of these variables. In an alloy, where one species is highly segregating, the solute can also control the grain size and therefore the stress. Based on this hypothesis, this work has elucidated how alloying effects in the residual growth stresses for a series of W-Cr, W-Fe, and Fe-Cr thin films. In addition, a molecular dynamics (MD) model for the growth of elemental W and Fe films was constructed to understand how different microstructures and processing variables control stress.