Application of Penta-Di-Methyl-Amino-Tantalum to a Tantalum Source in Chemical Vapor Deposition of Tantalum Oxide Films

Penta-di-methyl-amino-tantalum (Ta[N(CH3)2]5), a new source chemical of Ta in TaO chemical vapor deposition (CVD), has been studied. TG and DTA measurements show that Ta[N(CH3)2]5 is chemically stable up to about 150°C and vaporizes at a temperature of 80°C. TaO films were deposited by LP-CVD at temperatures of 380~520°C, by using the new chemical Ta[N(CH3)2]5 and O2. The deposition rate of TaO with Ta[N(CH3)2]5 is higher than that with Ta(OC2H5)5, a conventional Ta source. The TaO CVD using Ta[N(CH3)2]5 and O2 yields a good step coverage. Although the as-deposited TaO films are oxygen poor in film composition, annealing in an oxidizing ambient improves the stoichiometry and reduces the leakage current.