Microstructure and electrical properties of (Pb,La)(Zr,Ti) O-3 films crystallized from amorphous state by two-step postdeposition annealing

Dense amorphous lead lanthanum zirconate titanate (PLZT) films with composi tion (Pb0.925La0.075)(Zr0.4Ti0.6)(0.981)O-3 Were deposited on Pt/MgO(100) s ubstrates by rf-magnetron sputtering without heating the substrates and wer e subsequently crystallized by two-step postdeposition annealing and postde position annealing after chemical-oxidation treatment using ultrasonic-wave vibrations. The optimum soaking temperature of the crystal growth process in the two-step annealing process to crystallize as-deposited PLZT films Wa s determined to be 750 degreesC based on the measurements of the crystallin ity and the degree of c-axis orientation. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) observations revealed that the dist inct grain growth and sufficient crystallization for PLZT films were yielde d by postannealing after chemical-oxidation treatment. PLZT films fabricate d by postannealing after chemical-oxidation treatment had symmetric, slim a nd rectangular hysteresis loop shapes with the remanent polarization 2P(r) (equal sign with dot above and below) 51 muC/cm and the coercive field 2E(c ) (equal sign with dot above and below) 73 kV/cm. Based on the results of A FM observations and electrical properties, the present process with postdep osition annealing after chemical-oxidation treatment shows great promise as a practical process for crystallizing ferroelectric thin films from the am orphous state.