Preferred orientations in polycrystalline SnO2 films grown by atmospheric pressure chemical vapor deposition

The effects of film thickness, tin precursor nature, flow rate, and nucleation layers on the preferred growth direction of polycrystalline SnO2 films deposited on soda lime glass substrates were studied. By analyzing tin oxide layers deposited at different flow rates with X-ray diffraction, it was found that the predominate mechanism of SnO2 chemical vapor deposition was oriented overgrowth when monobutyltin-trichloride and dibutyltindiacetate were used as a tin precursors. In the same manner, the deposition of SnO2 from tetrabutyltin and phenyltin-trichloride was found to be governed by homogeneous nucleation. Atomic force microscopy, X-ray studies and application of a periodic bond chain theory indicated that polycrystalline SnO2 film surfaces deposited with monobutyltin-trichloride and dibutyltin-diacetate were formed by pyramidal based grains (200 × 300 nm) with (111) facets having (200) as a predominated growth direction. Tetrabutyltin and phenylbutyltin-trichloride deposited SnO2 films had (211) and (301) as preferred orientations formed by (101) contact twins. A nucleation layer approach was discussed in relation to improving the texture of the polycrystalline SnO2.