Title :
Low temperature preparation of fatigue free Bi4Ti3 O12 thin films by MOCVD and their electrical properties
Author :
Kijima, Takeshi ; Nagata, Masaya ; Matsunaga, Hironori
Author_Institution :
Functional Devices Lab., Sharp Corp., Chiba, Japan
Abstract :
We have investigated the low temperature MOCVD method to form Bi 4Ti3O12 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. 100 nm-Bi4Ti3O12 thin films grown at 400°C showed an excellent smooth surface morphology and had good electrical properties, namely, remanent polarization, Pr=11 μC/cm2, coercive field, Ec=90 kV/cm and low leakage current, IL=7×10-9 A/cm2 at 3 V. Additionally, for the first time, fatigue free property was confirmed up to 1×1012 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 μC/cm2
Keywords :
bismuth compounds; chemical vapour deposition; ferroelectric thin films; titanium compounds; 400 C; Bi4Ti3O12; Bi4Ti3O12 thin film; coercive field; crystallization; electrical properties; fatigue; grain structure; leakage current; low temperature MOCVD; nonvolatile ferroelectric memory; preferred orientation; remanent polarization; surface morphology; switching cycle; ultrathin double buffer layer; Bismuth; Buffer layers; Crystallization; Fatigue; Ferroelectric materials; MOCVD; Nonvolatile memory; Surface morphology; Temperature control; Transistors;
Conference_Titel :
Applications of Ferroelectrics, 1996. ISAF '96., Proceedings of the Tenth IEEE International Symposium on
Conference_Location :
East Brunswick, NJ
Print_ISBN :
0-7803-3355-1
DOI :
10.1109/ISAF.1996.602759
