Low leakage current and good ferroelectric properties of SrBi2(Ta0.7Nb0.3)2O9-Bi3TiTaO9 solid solution thin film

(1-x)SrBi2(Ta0.7Nb0.3)(2)O-9+xBi(3)TiTaO(9) (x=0-0.5) solid-solution (SBTN+BTT) films of low defect contents were directly crystallized on (111)Pt/Ti/SiO2/Si substrates at 650 degreesC by metalorganic chemical vapor deposition. The deposited films showed a strong (103) orientation. The remanent polarization (P-r) of the directly crystallized SBTN (x=0) was very small. However, the P-r value increased to 7.1 muC/cm(2) by adding 30% of BTT (x=0.3) and was almost equal to that of Sr0.8Bi2.2(Ta0.7Nb0.3)(2)O-9(S0.8B2.2TN), which is widely studied for nonvolatile memory applications. The leakage current density of the SBTN+BTT solid solution was on the order of 10(-8) A/cm(2) for fields up to 200 kV/cm due to its low defect contents character, while that of S0.8B2.2TN was above 10(-6) A/cm(2) due to the existence of defects in the Sr sites. The solid-solution film showed a fatigue-free character. (C) 2001 American Institute of Physics.