INFLUENCE OF BUFFER LAYER INSERTION AND ANNEALING MODE UPON MICROSTRUCTURES AND FERROELECTRIC CHARACTERISTICS OF SOL-GEL-DERIVED PB(ZR-X,TI-1-X)O-3 THIN-FILMS

As a continuation of our previous work, PZT alms with the Zr/Ti ratio varied from 40/60 to 70/30 were prepared by a sol-gel method, and the effects of PZT(120/52/48) buffer layer insertion and the annealing mod e were investigated. The results indicate that, irrespective of the an nealing mode, unbuffered PZT films with a Zr/Ti ratio of 40/60 to 60/4 0 exhibit (111)-preferred orientation, whereas buffer layer insertion induces growth with (100) orientation. This is in contrast to the case of PZT(70/30) him in which growth with (100) orientation is discernib le even when the buffer layer is not inserted. AFM observations reveal that the PZT films with the buffer layer display slightly smoother su rface microstructures than the unbuffered films. This is more clearly displayed in the case the him is subjected to RTA. Although the essent ial features of P-E hysteresis loops of the films are not significantl y affected by the annealing mode, conventional furnace annealing gener ally leads to slightly larger remanent polarization (Pr) than RTA. Pr vs Zr/Ti ratio curves for PZT films with and without the buffer layer invariably give a peak at Zr/Ti=60/40. Fatigue Life does not markedly improve even with an appropriate choice of the process factors in the film synthesis, which influence the microstructures and ferroelectric properties.