The effect of an iodine source on nucleation and film properties of Ru films deposited by chemical vapor deposition

The chemical vapor deposition of Ru films from (2,4-dimethylpentadienyl)(ethylcyclopentadienyl)Ru and O2 was carried out both with and without CH3I addition. X-ray photoelectron spectroscopy indicates that the addition of CH3I does not significantly increase the amount of carbon in the films. Adsorbed iodine on the growing film surface results in denser, more uniform nucleation and smaller-grained, smoother films. The root-mean-square roughness of 60 nm films decreased from 8.42 to 5.62 nm for no CH3I and CH3I addition, respectively. Adsorbed iodine segregates through the films to the surface during growth, resulting in a continuously depressed deposition rate. The adsorbed iodine blocks oxygen dissociation sites, reducing the oxygen supply available to decompose the ligands of the Ru precursor.