Crystallinity Improvement of Ferroelectric BiFeO_3 Thin Film by Oxygen Radical Treatment

摘要

Oxygen radical treatment was applied to sputter-deposited BiFeO_3 (BFO) thin film which is expected to be used for ferroelectric memories, sensors and solar cells. The oxygen radicals were produced by a microwave excited high-density Kr/O_2 plasma. It was found from X-ray diffraction (XRD) that the crystallization temperature of the BFO film could be reduced to 350 ℃ by applying the oxygen radical treatment before the annealing. The (110) peak area which shows the crystallinity of BFO was by 4 times than that of the BFO film annealed at 500 ℃ without the oxygen radical treatment. From results of XRD and X-ray photoelectron spectroscopy (XPS), the stoichiometry was dramatically improved and this suggests that the oxygen radical , treatment effectively creates the nucleation cites of BiFeO_3 and reduces oxygen vacancy defects.