La-doped effect on the ferroelectric properties of Bi4Ti3O12–SrBi4Ti4O15 thin film fabricated by pulsed laser deposition

Bi 4 Ti 3 O 12 – SrBi 4 Ti 4 O 15 (BT–SBTi) thin film was fabricated successfully on Pt/TiO2/SiO2/Si(110) substrates by the pulsed laser deposition technique. Films annealed at 650 °C by the rapid temperature process (RTP) have Pr=12 μC/cm2. But, the fatigue behavior has been observed although no obvious decrease in Pr up to 105 s retained time in the BT–SBTi capacitor. After being La doped, the Bi3.25La0.75Ti3O12–SrBi4Ti4O15 (BLT–SBTi) has fatigue free properties. Pr=13.5 μC/cm2 was measured in a BLT–SBTi film of 300 nm thickness. It did not show any significant fatigue up to 1010 switching cycles above the applied field of 250 kV/cm. It also has good retention properties. The field dependence of fatigue behavior and La-doped effect are discussed.