Anisotropic island growth: A new approach for thin film deposition

COLL 442

Lian Guo, lguo@jhu.edu and Peter C. Searson, searson@jhu.edu. Department of Materials Science and Engineering, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218
Electrochemical deposition of metals onto foreign substrates usually occurs through Volmer-Weber island growth, and hence the structure and properties of thin films are critically dependent on the mechanism of nucleation and growth. High nucleus densities are essential for achieving island coalescence at small thickness. Here we demonstrate a new approach to control thin film microstructure through control of island geometry. By promoting anisotropic island growth, film coalescence can be achieved at smaller thickness and with lower island densities. The larger grain size of the resulting thin film can increase conductivity, increase the threshold current for electromigration, and reduce the concentration of grain boundary impurities.