Title :
A new ferroelectric material for use in FRAM: lanthanum-substituted bismuth titanate
Author :
Noh, T.W. ; Park, B.H. ; Kang, B.S. ; Bu, S.D. ; Lee, J.
Author_Institution :
Dept. of Phys., Seoul Nat. Univ., South Korea
Abstract :
SrBi2Ta2O9 (SBT) thin films have attracted much attention due to their fatigue-free properties for ferroelectric random access memory (FRAM) applications. It was believed that the fatigue-free characteristics of SBT should originate from the presence of the (Bi2O2)2+ layers in the Bi-layered perovskite structure. However, Bi4Ti3O 12 (BTO) films showed fatigue failures although they have the same crystal structure and the (Bi2O2)2+ layers. Recently, we determined the differences in SBT and BTO films using XPS studies, and claimed that the oxygen chemical stability in the perovskite layers should play an important role in the fatigue-free behaviors. Based on this finding, we substituted some of the Bi ions with La ions to obtain ferroelectric Bi3.25La0.75Ti3O12 films. In addition to fatigue-free characteristics, these new materials have excellent properties for FRAM applications, including a low processing temperature and a large remnant polarization value
Keywords :
X-ray photoelectron spectra; bismuth compounds; dielectric polarisation; ferroelectric storage; ferroelectric thin films; lanthanum compounds; random-access storage; Bi3.25La0.75Ti3O12; FRAM; XPS studies; fatigue-free characteristics; ferroelectric random access memory; ferroelectric thin films; processing temperature; remnant polarization value; Bismuth; Chemicals; Fatigue; Ferroelectric films; Ferroelectric materials; Nonvolatile memory; Random access memory; Stability; Temperature; Transistors;
Conference_Titel :
Applications of Ferroelectrics, 2000. ISAF 2000. Proceedings of the 2000 12th IEEE International Symposium on
Conference_Location :
Honolulu, HI
Print_ISBN :
0-7803-5940-2
DOI :
10.1109/ISAF.2000.941548
