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发布时间：2019-11-04

论文类型：期刊论文

发表时间：2019-10-21

发表刊物：JOURNAL OF APPLIED PHYSICS

收录刊物：SCIE、EI

卷号：126

期号：15

ISSN号：0021-8979

摘要：Ferroelectricity in calcium doped hafnium oxide (Ca:HfO2) thin films has been experimentally proved for the first time in this work. All films prepared by chemical solution deposition exhibited smooth and crack-free surfaces, which were observed using an atomic force microscope. After 10(4) field cycling, a maximum remanent polarization of 10.5 mu C/cm(2) was achieved in HfO2 films with 4.8 mol. % Ca content. Meanwhile, the breakdown of the film occurred after 7 x 10(6) electric cycles. A phase transition from the monoclinic phase to cubic/orthorhombic phases was observed with increasing Ca concentration. We suggest the change in oxygen vacancy concentration as the origin of phase evolution, which was confirmed by X-ray photoelectron spectroscopy analysis. These results open a new pathway for realizing ferroelectricity in HfO2-based films. Published under license by AIP Publishing.