KrF laser CVD of titanium oxide from titanium tetraisopropoxide

Abstract

Titanium oxide films were prepared by KrF laser CVD from gaseous titanium tetraisopropoxide in an atmosphere of helium gas, and also of oxygen-containing helium gas as well. In both cases, the deposition rate was found to increase approximately linearly with increasing laser fluence, though the rate observed in the presence of oxygen was much greater than the rate found in the other case. The oxide deposits formed in the absence of oxygen consisted of TiO2 (anatase) and Ti3O5, while the deposits formed in the presence of oxygen consisted of anatase with small amounts of rutile. In the latter case, the deposits exhibited a strong preferred orientation of crystal planes, with (112) and (220) planes being oriented parallel to the substrate surface, depending on the magnitude of laser fluence. when viewed from a morphological standpoint, the oxide film formed in the absence of oxygen consisted of somewhat loose aggregated crystallites of anatase and Ti3O5, while the film formed in the presence of oxygen consisted of compact aggregates of titanium dioxide crystallites. Moreover, a possible cause of formation of Ti3O5 was suspected.