Although high-quality SnO2 films have been prepared above 400 degrees C, we prepared highly-conductive transparent F-doped SnO2 films below about 350 degrees C and at high growth rates, using a new raw material system of Sn(CH3)(4), O-2 containing 5 mol.% O-3, and HF-acid. At a substrate temperature of 350 degrees C, the films, which had properties such as sheet resistances of 1.6 and 4.5 Ohm/square, resistivities of 3.4 and 4.5 X 10(-4) Ohm cm, and transmittances including substrates of 70% and 80% at 550 nm, were prepared by thermal-CVD and photo-CVD (chemical vapour deposition), respectively. Several optical and electrical properties of the films prepared by both CVD methods were compared.