Amorphous thin films of composition Ti(x)Si(1-x)O2 have been grown by low-pressure vapor deposition on silicon (100) substrates using Si(OEt)4 and either Ti(O(i)Pr)4 or anhydrous Ti(NO3)4 as the sources of SiO2 and TiO2, respectively. RBS revealed that x (from the formula Ti(x)Si(1-x)O2) was dependent upon the choice of TiO2 precursor. For films grown using TTIP-TEOX x could be varied by systematic variation of the flow of N2 through the precursor vessels or the deposition temperature. For the case of TN-TEOS x remained close to 0.5. The results suggested the existence of a specific chemical reaction between TN and TEOS prior to film deposition.