Vapor pressure of precursors for CVD on the base of platinum group metals

Metal beta-diketonates are broadly used in the processes involving depositi on of different types of coatings by CVD. Acetylacetonates of platinum grou p metals are the most suitable precursors for use in highly effective CVD p rocesses because of their thermal properties, low price of initial ligand a nd accessible synthesis methods. Much attention is given to the investigati on of such an important property as volatility, which is necessary to optim ize the parameters of coating deposition. At present, a lot of experiments studying temperature dependencies of saturated vapor pressure of volatile m etal chelates have been carried out by different methods. However, the data on vaporization parameters often do not coincide with each other. In order to consider the reasons of such, differences, we measured the temperature dependencies of saturated vapor pressure of acetylacetonates of palladium(I I) (1), platinum(II) (2), rhodium(III) (3), iridium (III) (4), ruthenium(II I) (5) by flow and Knudsen methods. This allowed extending the temperature range within which vapor pressure was measured. The thermodynamic parameter s of phase transition from crystal to gas were calculated. The comparison w ith the literary data obtained by static method with the membrane zero-gaug e was carried out; the differences were enunciated and explained. The resul ts obtained in the study were co-processed. The following meanings of the c oefficients A and B in equation ln P-atm = - (A/T) + B were obtained for th e investigated complexes: 13425; 22,05 (1); 12737; 20,19 (2); 14290; 22,97 (3); 15391; 25,88 (4); 15228; 25,56 (5) (flow method).