Nucleation and growth of Cu films during the initial stage of chemical vapor deposition

Abstract

The nucleation and growth of Cu nanoparticles during the initial stage of film growth by chemical vapor deposition was investigated using transmission electron microscopy and energy dispersive x-ray spectroscopy analysis. Cu nanoparticles did not migrate on the SiO2 surface because the Cu nanoparticles were deposited by autocatalytic reactions onto pre-existing nuclei, and therefore were strongly bonded to the surface. The initial growth mechanism of Cu nanoparticles appears to be that Cu particles deposit by surface reaction onto pre-existing nuclei, grow to become nanoparticles, and these nanoparticles form amorphous Cu islands. The amorphous Cu islands grow to become larger islands that consist of partially-crystallized Cu. The crystallized Cu particles then begin to form on the amorphous Cu phases. With increasing deposition time, the amorphous Cu phases completely convert into crystalline phases to form a crystalline film.