THERMAL PROPERTIES OF Ir(I) PRECURSORS: ACETYLACETONATO(1,5-CYCLOOCTADIENE)IRIDIUM(I) AND (METHYLCYCLOPENTADIENYL)(1,5-CYCLOOCTADIENE)IRIDIUM(I)

摘要

Volatile compounds of iridium are broadly used in the processes of deposition of different type of coatings by CVD. Thermal properties of perspective iridium(I) precursors for CVD processes were investigated. Thermogravimetric analysis for acetylacetyonato(l,5-cyclooctadiene) iridium(I) ((acac)Ir(cod)) and (methylcyclopentadienyl)(l,5-cyclooctadiene)iridium(I) ((MeCp)lr(cod)) was carried out in inert atmosphere (He) and in vacuum. Temperature dependencies of the saturated vapor pressure for these compounds were investigated. Thermodynamic parameters of vaporization process were determined. Thermal decomposition of the vapor of compounds was investigated in vacuum within temperature range 200-570℃ and in the presence of oxygen in the reaction region within temperature range 200-450℃. The composition of gaseous products that come directly from the reaction region was determined by means of mass spectrometry. In vacuum, (MeCp)Ir(cod) is decomposed at a temperature about 450℃ with the evolution of gaseous (cod) and (MeCp), while (acac)Ir(cod) is decomposed at a temperature about 310℃ with the evolution of gaseous (cod), H(acac) and C_8H_8. In oxygen, the temperatures of complex decomposition substantially decrease to 200℃ and become approximately equal for both complexes. The major gas-phase products of the reaction between complexes and oxygen are CO_2, CO and H_2O. The mechanisms of thermal decomposition of complexes in the interaction with the surface are discussed.