Evaluating precursors for the sustainable gas-phase deposition: phase transition thermodynamics of volatile iridium(III) β-diketonates

The energetically developing metal–organic chemical vapor deposition (MOCVD) of Ir-based coating has been demanding precursors with properly defined thermal properties since the volatilization thermodynamics of a MOCVD precursor is highly answerable for the functional properties of a target material. The literature and our data have been amassed, uniformly processed, and evaluated for the set of iridium(III) β -diketonates. The restriction and scatter of the data have been observed. To resolve the contradiction, new data on sublimation and vaporization vapor pressures have been obtained by flow and static methods. To broad temperature interval to that utilized in MOCVD, a combination of empirical and experimental methods has been applied. As a result, a reliable set of data on thermodynamic parameters (saturated vapor pressure, enthalpy and entropy of sublimation and vaporization) has been acquired. Vapor pressure temperature dependences operating over a wide temperature range admit extrapolation of vapor pressure values to required temperatures. This benefit could be used to define the temperature regimes of film deposition by MOCVD with iridium(III) β -diketonate as precursors.