(La_(0.5)Sr_(0.5))CoO_3为电极的Pb(Zr_(0.4)Ti_(0.6))O_3和Pb(Zr_(0.2)Ti_(0.8))O_3铁电电容器结构及电学性能

Structure and Electrical Properties of Pb(Zr_(0.4)Ti_(0.6))O_3 and Pb(Zr_(0.2)Ti_(0.8))O_3 Ferroelectric Capacitors Based on (La_(0.5)Sr_(0.5))CoO_3 Electrode

分别采用磁控溅射法和溶胶-凝胶法(Sol-gel)制备了(La0.5Sr0.5)CoO3(LSCO)和Pb(Zr1-xTix)O3(PZT)薄膜,在Pt(111)/Ti/SiO2/Si基片上构架了LSCO/Pb(Zr0.4Ti0.6)O3(PZT(40/60))/LSCO和LSCO/Pb(Zr0.2Ti0.8)O3(PZT(20/80))/LSCO铁电电容器,研究了两种铁电电容器的结构和性能。XRD结构分析表明:两种四方相的不同Zr/Ti比例的PZT薄膜均为结晶良好的多晶钙钛矿结构。在5 V测试电压下,LSCO/PZT(40/60)/LSCO和LSCO/PZT(20/80)/LSCO两种铁电电容器的剩余极化强度(Pr)和矫顽场(Ec)分别为:28μC/cm2和1.2 V以及32μC/cm2和2 V。相对于PZT(40/60),PZT(20/80)具有较大的剩余极化强度和矫顽场,是由于其矩形度(c/a)较大。两种电容器都具有较好的脉宽依赖性和抗疲劳性。在5 V的测试电压下,LSCO/PZT(40/60)/LSCO电容器的漏电流密度为3.2×10-5A/cm2,LSCO/PZT(20/80)/LSCO电容器的漏电流密度为3.11×10-4A/cm2,经拟合分析发现:在0～5 V的范围内,两种电容器都满足欧姆导电机制。

（ La0.5 Sr0. 5 ） CoO3/Pb （ Zr0. 4Ti0.6 ） O3/（ La0. 5 Sr0.5 ） CoO3 and （ La0. 5 Sr0.5 ） CoO3/Pb （ Zr0.2Ti0.8 ） O3/ （La0.5 Sr0.5 ）CoO3 ferroelectric capacitors were fabricated on Pt （111）/Ti/SiO2/Si substrates, in which （La0.5Sr0.5）CoO3（LSCO） and PbZr1-xTi, O3 （PZT） films were prepared by magnetron sputtering and sol- gel, respectively, and the structural and physical properties were investigated. X-ray diffraction （XRD） reveals that both polycrystalline films are well-crystallized with perovskite structure. Measured at 5 V, remanent polafization（Pr） and coercive voltage （Ec） of the LSCO/PZT（40/60）/LSCO and LSCO/PZT （20/80）/LSCO capacitom are 28 μC/cm2, 1.2 V and 32 μC/cm2, 2 V, respectively. Both the Pr and Eo of LSCO/PZT（20/80）/LSCO are higher, which is mainly contributed to its larger tetragonality. Both the capacitors have good pulse width-dependence and fatigue resistance. The leakage current densities of LSCO/PZT（40/60）/LSCO and LSCO/PZT（20/80）/LSCO, measured at 5 V, are 3.2×10-5 and 3.11×10-4A/cm2, respectively. According to fitting, both capacitors satisfied the ohmic conductive behavior.