Process-Controlled Domain Switching and Improved Ferroelectric Properties in Lanthanum-Modified Lead Zirconate Titanate Films

In the present study, the effect of processing parameters like annealing temperature, excess of lead (Pb) content, and film thickness on the crystallographic orientation, dielectric and ferroelectric properties of PLZT (Pb/La/Zr/Ti: 92/8/52/48) films are investigated. For the investigation, PLZT films were prepared on Pt/Ti/SiO2/Si substrate by chemical solution deposition method and annealed at different temperatures (600, 625, 650, 675, and 700 degrees C). Diverse growth orientation was observed for different annealing temperatures that gave rise to modified electrical properties in the PLZT films. Comparative studies on processing temperature exhibited improved ferroelectric properties in 650 degrees C annealed PLZT film, which is attributed to its crystallinity (Full width at half maximum, FWHM101 = 0.49 degrees) and texture coefficient (gamma = 0.832). Excess Pb content (3 wt.%) yielded improved ferroelectric properties in PLZT film with a similar to 10% increment in domain switching. The PLZT film with 3 wt.% Pb-excess content showed an ASTM class 5B adhesion on Pt/Ti/SiO2/Si substrate, a nano-hardness value of 7894.43 MPa, and a Young's modulus value of 143.05 GPa. To further study the effect of process control parameters on PLZT film, variation of thicknesses (492, 768, and 1500 nm) was studied for 3 wt.% Pb-excess film. The study showed considerable domain switching (switching current = 58.10 mu A at 40 kV/cm), improved dielectric constant (similar to 2750), higher polarization (P-max = 71.4 mu C/cm(2)) at a low electric field 334 kV/cm and low leakage current for 1500 nm thick PLZT film. A total energy storage density of similar to 26 J/cm(3) at 1020 kV/cm and tunability of 68.46% at similar to 200 kV/cm was achieved for PLZT film with 3 wt.% excess Pb.