Epitaxial ferroelectric Y-doped HfO2 film grown by the RF magnetron sputtering

YO1.5-doped HfO2 films were deposited on yttria-stabilized zirconia substrates by RF magnetron sputtering at room temperature and under various atmosphere conditions. The deposited films were treated by rapid thermal annealing under both O-2 and N-2 flows. Epitaxial films with the orthorhombic phase, which is expected to exhibit ferroelectricity, are obtained under all conditions. The deposition in Ar atmosphere provided good ferroelectricity, while the deposition with O-2 resulted in a low breakdown voltage inhibiting ferroelectricity. Current density-voltage characteristics show a significant increase in leakage current by the deposition in atmosphere containing O-2 and also annealing under O-2 flow. These results indicate that the treatment in atmosphere containing O-2 leads to the degradation of insulation properties. (C) 2018 The Japan Society of Applied Physics