Thin homogeneous tantalum oxide films have been prepared on Si(100) substrates by spin-coating using the sol-gel approach as well as a novel VUV irradiation step using a 172 nm excimer lamp. The effects of spin-on speed, irradiation time and substrate temperature on the films formed have been studied. X-ray photoelectron spectroscopy (XPS) was employed to examine the elemental content during the process and showed that the carbon content, which is considered to be harmful to the electrical properties, can be reduced to the extent of being essentially zero. Ellipsometry, Fourier transform infrared spectroscopy, capacitance-voltage and current-voltage measurements were also employed to characterise the oxide films prepared at different substrate temperatures in the range of 100 degrees C to 450 degrees C and indicate that some of the films were of high quality. A significant reduction in the leakage current has been achieved by this technique without any high-temperature annealing.