Lithium niobate-tantalate films with the composition LiNb0.5Ta0.5O3 and very high c-axis orientation were grown on (1 0 0) and (1 1 1) Si substrates by using the thermal plasma spray CVD method. It is demonstrated that the substrate temperature is the key factor governing film orientation and crystallinity. The film direction could be varied from (0 0 6) to (0 1 2) by controlling the deposition temperature. Under optimal growth conditions, 97% c-textured films could be grown on both thick and very thin intermediate SiO2 layers. A (0 0 6) rocking-curve full-width at half-maximum value could achieve 3.7, by using the optimal deposition temperature. The growth rate applied was equal to 160-340 nm/min.