CaBi<SUB>2</SUB>Ta<SUB>2</SUB>O<SUB>9</SUB> ferroelectric thin films prepared by pulsed laser deposition

Thin films of CaBi2Ta2O9 (CBT) were deposited on Pt/TiO2/SiO2/Si substrates using the pulsed laser deposition technique at temperatures ranging from 500 to 700&#176; C. The presence of (115) and (0010) orientations confirm the phase formation at the lower temperature (500&#176; C). Microstructure evolution of CBT films with oxygen pressure of 100-200 mTorr at a substrate temperature of 650&#176; C shows that the films deposited at lower pressure have a relatively smaller grain size and less surface roughness. The films grown at 650&#176; C exhibited a maximum polarization of (2Pm) 17 &#181; C/cm2, remanent polarization of (2Pr) 8 &#181; C/cm2 and coercive field of (Ec) 128 kV/cm, with fatigue endurance up to 1010 switching cycles. The higher dielectric constant (~115 at 100 kHz) with a relatively lower dissipation factor (0.02) at higher growth temperature (700&#176; C) was explained by the increased grain size. The higher leakage current density (~10-7 A/cm2) at higher deposition temperature is attributed to the interfacial diffusion of the film and the substrate