Physical and Electrical Properties of Tantalum Oxide Thin Films Deposited by Low Pressure Chemical Vapor Deposition

ABSTRACTTa2O5 films suitable for DRAM use have been deposited on silicon, polysilicon, and SiO2 by LP-CVD from Ta (OC2H5)5 and O2. Uniformity, reproducibility, and conformality are excellent. Annealed films are polycrystalline, and their surfaces are characterized by 2 nm high, 1 mgr;m diameter nucleation centers surrounded by circular crystallization fronts. The electrical properties of annealed films are dominated by a SiO2-rich layer which forms between the Ta2O5 and the silicon or polysilicon substrate.