Solubility of bis-(2,2,6,6-tetramethyl-3,5-heptanedionato)copper(II) in mixed supercritical CO2 and H2 systems for application in supercritical fluid deposition of Cu

We measured the solubility of bis-(2,2,6,6-tetramethyl-3,5-heptanedionato)copper(II) (Cu(tmhd) 2 ) in pure supercritical CO 2 (scCO 2 ) and binary mixtures of H 2 and scCO 2 at 40–100 °C and 11–20 MPa using spectrometric method. The solubility in scCO 2 was dependent on the density of CO 2 . The addition of H 2 to the scCO 2 had negative impact on the solubility, and the solubility was proportional to density of CO 2 with a constant mole fraction of H 2 . The equations proposed by Mendez-Santiago and Teja as well as Sauceau et al. were able to correlate the solubility in the pure CO 2 and binary systems. This approach provides a framework to determine the precursor concentration for supercritical fluid deposition (SCFD) of Cu. The precursor feed system for optimal Cu-SCFD was discussed. In addition, the same effect was found with the addition of O 2 and N 2 into scCO 2 , suggesting that further investigation into the solubility of SCFD precursors in these binary systems is warranted.