Low temperature preparation of fatigue free Bi4Ti3O12 thin films by MOCVD and their electrical properties

We have investigated the low temperature MOCVD method to form B14Ti3O12 thin films with suitable electrical properties for nonvolatile ferroelectric memory applications. An ultra thin double buffer layer (5nm-Bi4Ti3O12/5nm-TiO2) was used to control the crystallization and a fine grain structure of Bi4Ti3O12 at a low growth temperature was obtained. 100nm-Bi4Ti3O12 thin films grown at 400 degrees C showed an excellent smooth surface morphology and had good electrical properties, namely, remnant polarization, Pr=11 mu C/cm(2), coercive field, Ec=90 kV/cm and low leakage current, IL=7x10(-9) A/cm(2) at 3V. Additionally, for the first time, fatigue free property was confirmed up to 1x10(12) switching cycles. Furthermore, it was found that the Bi4Ti3O12 thin films with a bismuth rich composition showed the (117) preferred orientation, and a very large Pr of 23 mu C/cm(2).