Atomic layer deposition of Ta-based thin films: Reactions of alkylamide precursor with various reactants

The growth mechanisms and film properties of atomic layer deposition (ALD) Ta-based thin films were investigated from alkylamide precursor [Ta(NMe2)5, (PDMAT)]. The reactions of PDMAT with various reactants including water, NH3, oxygen, and hydrogen plasma were studied and the resulting film properties were investigated by various analysis techniques. For TaN ALD from NH3 and H plasma, the films were contaminated by considerable amount of carbon, while the Ta2O5 deposited from water and O plasma were quite pure. Also, nitrogen was incorporated for ALD from PDMAT and H plasma, while no nitrogen incorporation was observed for O-plasma based plasma enhanced-ALD of Ta2O5 except at high deposition temperature over 300°C. The results were comparatively discussed focusing on the differences in growth mechanism depending on reactants.