Low-pressure chemical vapor deposition of Cu on Ru substrate using CuI: Ab initio calculations

We elucidate the molecular mechanism of Cu deposition using copper(I) iodide (CuI) on Ru substrate by low-pressure chemical vapor deposition through ab initio electronic structure calculations. Using density functional theory calculations, we show that CuI molecules adsorb and decompose exothermically due to a strong adsorption of iodine atoms onto the Ru(001) surface. The rate-limiting step of the Cu deposition is found to be the desorption of iodine molecules from the Cu(111) surface, suggesting that the removal of iodine species is necessary to achieve the high-rate deposition of highly-conductive copper films for ultra large scale integration metallization.