Precursor dependent nucleation and growth of ruthenium films during chemical vapor deposition

Nucleation and film growth characteristics are reported during chemical vapor deposition of Ru on SiO2 using triruthenium dodecacarbonyl [Ru-3(CO)(12)] and ruthenium bis(di-t-butylacetamidinate) dicarbonyl [Ru(Bu-t-Me-amd)(2)(CO)(2)]. Films grown from Ru-3(CO)(12) follow the three dimensional (3D) Volmer-Weber growth mode. In contrast, films grown from Ru(Bu-t-Me-amd)(2)(CO)(2) follow the pseudo-layer-by-layer growth mode with two dimensional wetting layer islands forming before 3D particle growth is observed on the islands. A relationship between free isolated hydroxyl [(SiOH) i] group density and Ru nucleation density is found for Ru-3(CO)(12) and is associated with (SiOH) i acting as the reaction sites for activation of Ru-3(CO)(12) and in turn generating an adjustable adatom concentration. Carbon monoxide and ammonia addition to the gas phase during film growth from Ru(Bu-t-Me-amd)(2)(CO)(2) lead to smoother films by inducing surface reconstructions during the 3D phase of pseudo-layer-by-layer growth; these gases also lead to films with lower resistivity and lower crystalline character. (C) 2016 American Vacuum Society.