Morphology evolution of SiO2 films deposited by tetraethylorthosilicate/O3 atmospheric-pressure chemical vapor deposition on thermal SiO2

To understand the surface dependence of chemical vapor deposition using tetraethylorthosilicate and O-3, the evolution of the morphology of 5.3-mu m-thick oxide films deposited on thermal oxide was observed by scanning electron microscopy. The surface roughness and low etching resistance of the films was caused by different growth rates at different surface sites. Some sites grow much faster that other sites, evolving from island, to tree, and finally to continuous films. Because of this growth sequence, the film has high porosity and is rough. This growth mode might be caused by site-dependent tetraethylorthosilicate absorption rates.