CHEMICAL VAPOR-DEPOSITION OF CUOX FILMS BY CUL AND O-2 - ROLE OF CLUSTER FORMATION ON FILM MORPHOLOGY

CuO(x) films were deposited on silica substrates by the chemical vapor deposition (CVD) method, using CuI and O2 as source gases at low pressure in a tubular reactor. The growth mechanism to obtain a dense and uniformly distributed (in the axial direction in a tubular reactor) film was investigated. It was found that the occurrence of homogeneous nucleation caused an abrupt increase of deposition rate and made the film porous. Homogeneous nucleation can be prevented by properly selecting reactant concentration, reactor temperature, and reactor diameter. Based on an aerosol diffusion theory from laminar pipe flow, a method of predicting cluster size in this CVD reaction system was proposed. The result showed that the clusters formed by homogeneous nucleation had an average size of about 1 nm in diameter.