KINETICS OF SUBLIMATION OF COPPER(II) ACETYLACETONATE COMPLEX USED FOR CHEMICAL VAPOR-DEPOSITION OF COPPER-FILMS

The kinetics of sublimation of copper(II) acetylacetonate complex, Cu(C5H7O2)2, in pure hydrogen or argon was investigated by isothermal thermogravimetry at a temperature and pressure ranging from 140 to 210-degrees-C and 100 to 300 Torr, respectively. The sublimation rate of this compound was independent of time and was observed to be inversely proportional to the H2 or Ar pressure. The apparent activation energy of the sublimation process was equal to 105.3 +/- 9 kcal mol-1. The diffusion of copper complex vapor in the H2 or Ar gas phase from the boat to the cold wall of the reactor may be the rate-limiting step of the sublimation process. Chemical vapor deposition of pure copper films was performed for the first time by decomposition of this copper complex at low temperatures (220-250-degrees-C) in H2 or H2-Ar carrier gas. The structure or morphology of copper films tightly adherent to SiO2/Si substrates was found to depend on the deposition time, deposition temperature and composition of the gas phase used as a carrier gas.