ABSTRACT
FERROELECTRICITY OF HETEROEPITAXIAL Ba0.6Sr0 4T i03 ULTRATHIN FILMS
KAZUHIDE ABE, SHUICHI KOMATSU, NAOKO YANASE, KENYA SANO, and TAKASHIKAWAKUBO
Materials and Devices Research Laboratories, R&D Center, Toshiba Corp., Saiwai-ku Kawasaki 210, Japan
Remanent polarization (2Pr) larger than 0.4 C/m2 has been obtained in heteroepitaxial Bao.6Sro.4Ti03 (BSTO) films, even though the thickness was reduced to as thin as 26 nm. Ferroelectricity is induced by 2dimensional stress, which is caused by lattice mismatch between the dielectric film and the bottom electrode (SrRu03). The Curie temperature was confirmed to shift toward higher temperature by more than 200°C. These results constitute a significant advance toward the practical realization of ferroelectric nonvolatile memories with a large capacity of 256 M to 1 G bit.