Enhancement of Nanoscale Leakage Current Performance of Bismuth Ferrite Thin Films Using Conductive Oxide Electrodes

Thin BiFeO 3 (BFO) films with a thickness of 80 nm were grown on Pt/Ti/SiO 2 /Si(100) substrates at 350-550°C with and without a 100 nm thick LaNiO 3 (LNO) buffer. The growth of the BFO film with an LNO buffer promotes the appearance of highly (100)-crystallographic features. A high deposition temperature of 550°C yields BFO films with secondary phases. Secondary-ion mass spectrometry depth profiles show no obvious interdiffusion of constituent elements between the BFO and the LNO at growth temperatures of 350-450°C. The buffering of LNO markedly reduces the degree of the surface roughening of BFO films, which is determined by the growth temperature. The spatial distribution of the current image of BFO films grown at 350-450°C on the nanometer scale shows a considerable reduction in the nanostructural leakage current properties of BFO films upon the buffering of LNO because of the effective improvement in the film/electrode interface, chemical homogeneity, crystallinity, and surface roughness of the BFO films. Moreover, impurity phases in the BFO films grown at 550°C act as the dominant conduction path of leakage currents.