Deposition mechanism of gold by thermal evaporation: approach by charged cluster model

The charged cluster model states that chemical vapor deposition (CVD) begin s with gas-phase nucleation of charged clusters followed by cluster deposit ion on a substrate surface to form a thin film. Gold deposition by thermal evaporation was studied in a two-chambered CVD system in order to determine if this mechanism applies to the present case. The presence of nanometer-s ized gold clusters was confirmed by transmission electron microscopy (TEM). The charge on the primary clusters was found to be positive. Smaller clust ers were found to be amorphous and combined with clusters already deposited on a substrate surface to form larger amorphous clusters on the surface. L arger clusters were also observed by TEM to form after 120 and 300 s, These clusters exhibited a lattice structure and may have grown by attachment of small clusters in the gas phase, (C) 2000 Published by Elsevier Science B. V. All rights reserved.