Abstract: We have successfully demonstrated that high quality and high dielectric constant layers can be fabricated by low temperature photo-induced or -assisted processing.Ta₂O₅ and ZrO₂ have been deposited at t＜400 ℃by means of a UV photo-CVD technique and HfO₂ by photo-assisted sol-gel processing with the aid of excimer lamps.The UV annealing of as-grown layers was found to significantly improve their electrical properties.Low leakage current densities on the order of 10^-8 A/cm² at 1 MV/cm for deposited ultrathin Ta₂O₅ films and ca.10^-6 A/cm² for the photo-CVD ZrO₂ layers and photo-irradiated sol-gel HfO₂ layers have been readily achieved.The improvement in the leakage properties of these layers is attributed to the UV-generated active oxygen species O(1D) which strongly oxidize any suboxides to form more stoichiometric oxides on removing certain defects, oxygen vacancies and impurities present in the as-prepared layers.The photo-CVD Ta₂O₅films deposited across 10.16-cm Si wafers exhibit a high thickness uniformity with a variation of less than ±2.0% being obtained for ultrathin ca.10 nm thick films.The lamp technology can in principle be extended to larger area wafers, providing a promising low temperature route to the fabrication of a range of high quality thin films for future ULSI technology.

Key words: Excimer lamp, High-k dielectrics, Thin film, Chemical vapour deposition (CVD), Sol-gel pro-cessing