Thermal Stability, Sublimation Pressures, and Diffusion Coefficients of Anthracene, Pyrene, and Some Metal β-Diketonates

Abstract

Metal β-diketonates are often volatile enough to be useful as precursors of metals in vapor phase deposition processes, e.g., chemical vapor deposition (CVD). To engineer such processes, knowledge of vapor or sublimation pressures is essential because they determine the maximum theoretical growth rate and the composition. Gaseous diffusion coefficients are needed for calculation of Sherwood and Lewis numbers used to describe the mass transfer process. Such data are often either lacking or not well established. In the present communication, the thermal stabilities of copper(II) acetylacetonate, vanadium(III) acetylacetonate, zinc(II) acetylacetonate, ruthenium(III) acetylacetonate, thulium(III) acetylacetonate, and dysprosium(III) acetylacetonate are tested. Some of these compounds are sensitive to air (oxygen), and hence the studies have been performed in a glovebox to avoid any oxygen and moisture. The vapor pressures and the binary diffusion coefficients (in nitrogen or helium) for anthracene, pyrene, copper(II) acetylacetonate, and ruthenium(III) acetylacetonate are reported at temperatures between (339 and 443) K at ambient pressure. The enthalpies of sublimation are also deduced from the vapor pressure data. The discrepancies with literature data, found in some cases, are discussed.