Surface reactivity and oxygen migration in amorphous indium-gallium-zinc oxide films annealed in humid atmosphere

An isotope tracer study, i.e., O-18/O-16 exchange using O-18(2) and (H2O)-O-18, was performed to determine how post-deposition annealing (PDA) affected surface reactivity and oxygen diffusivity of amorphous indium-gallium-zinc oxide (a-IGZO) films. The oxygen tracer diffusivity was very high in the bulk even at low temperatures, e. g., 200 degrees C, regardless of PDA and exchange conditions. In contrast, the isotope exchange rate, dominated by surface reactivity, was much lower for O-18(2) than for (H2O)-O-18. PDA in a humid atmosphere at 400 degrees C further suppressed the reactivity of O-2 at the a-IGZO film surface, which is attributable to -OH-terminated surface formation. (C) 2013 AIP Publishing LLC.