Tantalum Oxide Films Formed by UV Photo-CVD Using Ozone and TaCl5

Abstract
A new UV photo-CVD is developed to fabricate thin films of high-dielectric-constant Ta2O5. The significant features of the new photo-CVD are the UV 254 nm irradiation and the use of pure O3 as an oxidant source. The as-grown films obtained at a low deposition temperature of 300°C show very low leakage current and remarkably good step coverage. UV irradiation during CVD is essential to improve the resistivity and dielectric breakdown strength of the film. This CVD method and understanding of the related mechanism may be applicable to fabrication technology of future VLSI's.