COMPARATIVE INSITU STUDY OF TANTALUM THIN-FILM OXIDATION IN ISOTHERMAL AND NON-ISOTHERMAL CONDITIONS

A comparative study has been made of the isothermal (T equals 700 K) and nonisothermal (T from 300 to 700 K) oxidation of Ta-films in air. Parabolic oxidation kinetics were observed for the isothermal study, while the nonisothermal oxidation exhibited logarithmic kinetics instead of the expected mixed logarithmic-parabolic characteristics. The nonisothermal oxidation behavior is attributed to the relative importance of oxygen dissolution in comparison to that in isothermal oxidation. Transmission electron microscopy and Auger electron spectroscopy depth profile studies show that thin films are composed of an amorphous solid mixture of Ta//2O//5, TaO and TaO//x (X less than 1) during isothermal as well as nonisothermal oxidation.