Pb(Zr_x,Ti_(1-x))O_3成分梯度铁电薄膜的制备、结构及电性能表征

PREPARATION, STRUCTURE AND CHARACTERISTICS ON COMPOSITIONALLY GRADED Pb(Zr_x,Ti_(1-x))O_3 FERROELECTRIC THIN FILMS

采用Sol-Gel方法,通过快速热处理,在Pt/Ti/SiO2/Si衬底上制备出Pb(Zrx,Ti1-x)O3成分梯度薄膜.经俄歇微探针能谱仪(AES)对制备的“上梯度”薄膜进行了成分深度分析,结果证实其成分梯度的存在.经XRD分析表明,制备的梯度薄膜为四方结构和三方结构的复合结构,但其晶面存在一定的结构畸变.经介电频谱测试表明,梯度薄膜的介电常数比每个单元的介电常数都大,但介电损耗相近.在10kHz时,上、下梯度薄膜的介电常数分别为206和219.经不同偏压下电滞回线的测试表明,上、下梯度薄膜均表现出良好的铁电性质,其剩余极化强度Pr分别为24.3和26.8μC·cm-2.经热释电性能测试表明,热释电系数随着温度的升高逐渐增加,室温下上、下梯度薄膜的热释电系数分别为5.78和4.61×10-8C·cm-2K-1,高于每个单元的热释电系数.

Compositionally graded Pb（ Zrx, Ti1-x ）O3 thin films were prepared on platinum-coated silicon substrates by Sol-Gel method and rapid heat-treatment. The composition depth profile of a typical up-graded film was determined by using a combination of auger electron spectroscopy and Ar ion etching. The results confirm that the processing method produces graded composition change. XRD analysis shows that the graded thin films possess the structure of tetragonal and rhombohedral. The dielectric constant of the graded thin films is higher than that of each thin film unit, but dielectric loss is near to each other. The dielectric constants of up-graded and down-graded thin films are 206 and 219 at 10 kHz, respectively. The hysteresis loops of the graded thin films show fine ferroelectric properties. The remanent polarizations of up-graded and down-graded thin films are 24.3 and 26.8 μC· cm^ -2, respectively. The pyroelectric coefficient of the graded thin films gradually increases with the temperature up, and is higher than that of each thin film unit. The pyroelectric coefficients of up-graded and down-graded thin films are 5.78 and 4.61 × 10^-8 C· cm^-2K^-1 at room temperature, respectively.