The Superiority of N₂O Plasma Annealing over O₂ Plasma Annealing for Amorphous Tantalum Pentoxide (Ta₂O₅) Films

Abstract

As-deposited tantalum pentoxide (Ta 2 O 5 ) films are amorphous. The films will remain amorphous after low-temperature O 2 or N 2 O plasma annealing. High-temperature annealing will produce polycrystalline films where grain boundaries can generate leakage current. It was found that N 2 O plasma annealing is superior to O 2 plasma annealing in terms of leakage current reduction. This can be easily explained by the lower energy required to break the nitrogen-oxygen bond in a N 2 O molecule compared to the energy required to break the O=O bond in an O 2 molecule. We also observed that there is less Si contamination, which may lead to leakage current, in the sample with N 2 O plasma annealing compared to the sample with O 2 plasma annealing.