Electrical and reliability characteristics of an ultrathin TaOxNy gate dielectric prepared by O-3 annealing

This letter describes a unique process for the preparation of high-quality tantalum oxynitride (TaOxNy) films via NH3 annealing of Ta2O5 followed by r eoxidation in an O-3 ambient for use in gate dielectric applications. Compa red with tantalum oxide (Ta2O5), a significant improvement in dielectric co nstant was obtained by the ammonia treatment. Low-temperature reoxidation i n an O-3 ambient resulted in a significantly reduced leakage current, Compa red with reoxidation in an O-2 ambient, TaOxNy films prepared by reoxidatio n in an O'(3) ambient show less charge trapping under electrical stress.