Ethanol-addition-enhanced, chemical vapor deposited tantalum oxide films from Ta(OC2H5)5 and oxygen precursors

An innovative chemical vapor deposition (CVD) technique of Ta2O5 film from Ta(OC2H5)(5) including ethanol and oxygen precursors is demonstrated in this paper. High deposition rate of approximately 10 nm/min is obtained by employing Ta(OC2H5)(5) including ethanol and oxygen precursors at 350 degrees C. Temperature-programmed decomposition analysis shows that decomposition of ethanol, adsorbed on the Ta2O5 film surface, into hydrogen and aldehyde begins at 250 degrees C. These results suggest that Ta2O5 film plays a role as a catalyst for dehydrogenation of ethanol. Under oxygen ambient, water seems to be easily generated on the Ta2O5 surface by reaction between the hydrogen and oxygen. Hydrolysis of ethoxide on the surface promotes deposition of Ta2O5 film. Carbon concentration included in the as-deposited Ta2O5 film can be remarkably reduced by the plasma oxygen annealing at 350 degrees C. Combination of the CVD at 350 degrees C and plasma-activated oxygen annealing at 350 degrees C provide favorable insulative properties for future dynamic random access memories and make it possible to form the film on the storage node while preventing oxidation of the storage node.