The decomposition and the degradation characteristics of Ba(TMHD)(2) and Sr(TMHD)(2) with storage time were analyzed using differential scanning calorimetry. Mass spectrometer monitoring of source vapors with Ar and NH3 carrier gases in an electron cyclotron resonance-plasma enhanced metal organic chemical vapor deposition system was also performed. Introducing NH3 as a carrier gas, significantly improved the volatility and the thermal stability of the precursors, as well as the uniformity and the surface smoothness of strontium carbonate films. Required vaporization temperatures of the precursors were lower with the introduction of NH3 gas than with conventional Ar carrier gas. The degradation with the storage time and with oligmerization at the evaporation temperature for Ba(TMHD)(2) was greater compared to Sr(TMHD)(2).