GRAIN-BOUNDARY STRUCTURE OF BI2O3-DIFFUSED BATIO3 BL CAPACITOR

The grain boundary structure of semiconductive BaTiO3 and Bi2O3-diffused BaTiO3 BL capacitor was studied using XRD, EDS, SEM, and AEM. Without SiO2, Ba6Ti17O40 (B6T17) phase was detected in the semiconductive BaTiO3 sample, and Ba4Ti13O30 (B4T13) and BaBi4Ti4O15 (BBIT) phases were found in the BL capacitor sample. On addition of SiO2, B6T17 and Ba2TiSi2O8 were found at the grain boundaries of the semiconductor, and B6T17, BTS, BBIT in the BL capacitor were found at the grain boundary. The di-hedral angle seen in the semiconductive sample was about 20-degrees, but after the Bi2O3 was diffused, it changed to 0-degrees. So it is suggested that the liquid phase containing bismuth has a very low viscosity compared with that of the liquid phase without bismuth, and it is easy to make microstructure of BL capacitor when bismuth oxide diffuses.