Preferred orientations in polycrystalline SnO 2 films grown by atmospheric pressure chemical vapor deposition

Abstract

The effects of film thickness, tin precursor nature, flow rate, and nucleation layers on the preferred growth direction of polycrystalline SnO 2 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 SnO 2 chemical vapor deposition was oriented overgrowth when monobutyltin-trichloride and dibutyltindiacetate were used as a tin precursors. In the same manner, the deposition of SnO 2 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 SnO 2 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 SnO 2 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 SnO 2.