Characteristics of some (MOD) thin film layer type compounds in the bismuth titanate lead titanate system

Layer type Aurivillius compounds of complex ferroelectric bismuth oxides have become important as thin films for nonvolatile, random-access memories(DRAMS). This paper reports the investigation of the formation of these compounds and their electrical properties, in the bismuth titanate-lead titanate system. Films were formed using the metallo-organic decomposition (MOD) spin-on solution process. These solutions were spun onto a platinized Si substrate and then fired at 700 degrees C to form 1 mu m thick films of bismuth titanate and lead titanate, The films were analyzed using microprobe and x-ray diffraction analyses. Next, the solutions were blended to give compounds from m = 4 to m = 7; where m is defined as the potential number of perovskite-like units between (Bi2O2)(+2) layers. The blended solutions were processed exactly like the bismuth titanate and lead titanate solutions. X-ray diffraction analysis was used to determine if Aurivillius layer compounds were formed. Ferroelectric hysteresis loops were correlated with the results obtained from the x-ray diffraction studies.