金属有机物热分解工艺制备PLZT铁电薄膜的晶化过程及其电性能研究

Crystallization and Electric Properties of PLZT Films Derivedfrom Metallorganic Precursors

采用MOD法制备了PLZT铁电薄膜.通过DTA研究了PLZT粉末和薄膜的晶化动力学.MOD法制备的PLZT材料,在420~570℃的温度范围内由非晶结构向钙钛矿结构转化,其粉体和薄膜的晶化活化能E_a分别为55kJ/mo1和70kJ/mo1,频率因子γ分别为450s^(-1)和1.4×10~4s^(-1).薄膜从非晶态向钙钦矿相的转化过程中要经过亚稳的焦绿石相的过渡,其E和γ分别为143 kJ/mo1和7.9×10~9s^(-1).经过550℃热处理得到的PlZT(8/65/35)铁电薄膜,相对介电常数为900,介电损耗为0.02(1kH2),饱和极化强度和矫顽场强分别为35.5μC/cm^2和124kV/cm.

Lead Lanthanum zirconate titanat (PLZT) films were prepared by metallor-ganic decomposition (MOD) method. Crytallization kinetics of PLZT powder and films(on Si substrate) have been studied, using DTA. Crystallization of perovskite structurefrom amorphous structure is in the temperature range of 420~570℃ with regard of thePLZT materials derived from MOD. For the powder and films of PLZT, activation ener-gies of crystallization are 55 kJ/mol and 70 kJ/mol with frequency factors 450 s-1 and 1.4 × 104 s-1 respectively. The trasition from metastalle pyrochlore phase to perovskitephase occurs during the crystallization of the film from amorphous phase, which activa-tion energy and freqency factor and 143 kJ/mol and 7.9 × 10-9 s-1. For PLZT (8/65/35) films annealed at 550℃,is 900, tg is 0. 002 (1 kHz), Ps is 35. 5 μC/cm2 and Ecis 124 kV/cm(50Hz).