Diagramas de fase CVD para la preparación de películas de iridio

Chemical vapor deposition (CVD) phase diagrams for the preparation of iridium films were calculated using Gibbs free energy minimization method. Iridium acetylacetonate (lr(acac)₃) was used as the precursor compound. Two gaseous mixtures were analyzed: lr(acac)₃-O₂-Ar and lr(acac)₃-Ar. The deposition temperatures were explored from 300 to 800°C, total pressures from 13.3 to 13.332 Pa and partial pressures of lr(acac)₃ gas and O₂ gas from 0.001 to 1.000 Pa. The lr-CVD diagrams predicted that without O₂ gas in the gaseous mixture, the solid films consist of two solid phases: lr+C. In contrast, with addition of O₂ to the gaseous mixture, the lr-CVD diagrams revealed different domains of condensed phases which include lrO₂, lrO₂+lr, lr and lr+C. These diagrams allow one to establish the total pressures and temperatures required to obtain a given film composition. The results predicted by the lr-CVD diagrams are in good agreement with those experimentally obtained.