Atmospheric pressure chemical vapour deposition of fluorine-doped tin(II) oxide from fluoroalkyltin precursors

Perfluoroalkytin compounds R((4-n))Sn(R-f)(n) (R = Me, Et, Bu, R-f = C4F9, n = 1; R = Bu, R-f = C4F9, n = 2, 3;R = Bu, R-f = C6F13, n = 1) have been synthesized, characterized by H-1, C-13, F-19 and Sn-119 NMR, and evaluated as precursors for the atmospheric pressure chemical vapour deposition of fluorine-doped SnO2 thin films. All precursors were sufficiently volatile in the range 84-136 degrees C and glass substrate temperatures of ca 550 degrees C to yield high-quality films with ca 0.79-2.02% fluorine incorporation, save for Bu3SnC6F13, which incorporated < 0.05% fluorine. Films were characterized by X-ray diffraction, scanning electron microscopy, thickness, haze, emissivity, and sheet resistance. The fastest growth rates and highest quality films were obtained from Et3SnC4F9. An electron diffraction study of Me3SnC4F9 revealed four conformations, of which only the two of lowest abundance showed close F center dot center dot center dot Sri contacts that could plausibly be associated with halogen transfer to tin, and in each case it was fluorine attached to either the gamma- or delta-carbon atoms of the R-f chain. Copyright (c) 2005 John Wiley & Sons, Ltd.