【作者】 孙正；

【导师】 李玲霞；

【作者基本信息】 天津大学 ， 微电子学与固体电子学， 2018， 博士

【摘要】 为满足电子元器件逐渐向小型化、集成化、多功能化方向的发展需求。本文以室温下具有较高介电常数、较低介电损耗并具有一定弥散相变的Ba(Zr_0.2Ti_0.8)O₃（BZT20）为研究对象,采用B位离子掺杂、A位离子掺杂以及A、B位离子共掺的方式对其进行掺杂改性,通过系统研究掺杂离子种类和含量对弥散相变和介电性能的影响,建立弥散相变程度与电容量温度变化率之间的联系,改善容温特性,完善高介效应的内部响应机制,最终制备出具有高介电常数（3×10⁴）、低介电损耗（0.05）和较好容温特性的BZT20体系;此外,探索稀土离子掺杂对Ba(Zr_0.15Ti_0.85)O₃储能性能和弛豫特性的影响。首先,采用固相反应法制备BZT20体系,系统研究烧结工艺对BZT20物相结构、显微形貌、致密度和介电性能的影响,获得最佳制备工艺条件:烧结温度为1350^oC,保温时间4小时,1k Hz下室温介电常数ε_RT=16164,介电损耗tanδ=0.01。其次,为了提高BZT20样品的介电常数,采用B位Nb⁵⁺离子和Cu²⁺离子掺杂,研究B位离子掺杂对BZT20介电常数和弥散相变影响机理,建立极化微区（Polar nano regions,PNRs）与弥散相变之间联系,基于Maxwell-Wagner界面极化理论和内部阻挡层电容器（Internal barriers layers capacitor,IBLC）模型,分析半导化晶粒对高介电常数影响机制,通过调整制备工艺和掺杂含量,将BZT20样品的介电常数提升一倍(ε_RT=35675)。再次,为了进一步降低BZT20的介电损耗,增强弥散相变,采用A位Bi³⁺离子、Li⁺离子和Ca²⁺离子掺杂,分析氧空位缺陷和晶粒尺寸对介电损耗的影响机理,建立PNRs尺寸变化与弥散相变和电容量温度变化率的内部响应机制,通过优化制备工艺和掺杂含量,将介电损耗降低一个数量级,同时制备出电容量温度变化率满足Y5V标准的BZT20材料体系。最后,为了综合提升BZT20的介电性能,采用两步烧结法制备A位Bi³⁺离子、B位Zn²⁺离子和Nb⁵⁺离子共掺杂的（1-x）BZT20-x Bi₂(Zn_2/3Nb_4/3)O₇体系,进一步优化其结构和介电性能,制备出性能更加优异的BZT20高介材料体系。在介电损耗维持相同量级的条件下（tanδ=0.05）,相比于其他满足Y5V标准的材料体系,其介电常数提升近一倍(ε_RT=32668),促进电子元器件小型化发展进程。另外,采用固相反应法制备Ba_1-xSm_2x/3(Zr_0.15Ti_0.85)O₃体系,研究Sm³⁺离子含量对PNRs尺寸的影响规律,建立PNRs尺寸与储能性能的联系,通过调整掺杂含量,获得具有较高储能密度（W₁=1.15J/cm³）的Ba_0.997Sm_0.002Zr_0.15Ti_0.85O₃材料体系,将Ba(Zr_0.15Ti_0.85)O₃样品的储能密度（W₁=0.4J/cm³）提升近两倍,且高于其他Ba Ti O₃基材料体系,是一种在储能领域具有潜在应用前景的高性能介电储能材料。更多还原

【Abstract】 In order to meet the development needs of electronic components gradually becoming smaller,integrated and multifunctional.In this paper,Ba(Zr_0.2Ti_0.8)O₃（BZT20）,which own high dielectric constant,low dielectric loss and a certain diffuse phase transition at room temperature,is doped by B site ions doping,A site ions doping and A、B sites ions co-doping.The diffuse phase transition is studied through the series of ions and content of doping ions.Through investigating the change of dielectric properties,the relationship between the degree of diffuse phase transition and the temperature coefficient of capacitance is established,and the temperature characteristics are improved and the internal response mechanism of high dielectric effect is perfected.Finally,the BZT20 system with high dielectric constant（3x10⁴）,low dielectric loss（0.05）and better temperature characteristics is prepared.In addition,effect of rare earth ions doping on the energy storage and relaxation properties of Ba(Zr_0.15Ti_0.85)O₃ is explored.Firstly,the BZT20 is prepared by solid-state reaction method.Effects of sintering process on the phase structure,microstructure,density and dielectric properties of BZT20 are studied.The optimum preparation conditions are obtained:the sintering temperature is 1350^oC,the dwell time is 4 hours,the dielectric constant at room temperature(ε_RT)is 16164 and the dielectric loss（tanδ）is 0.01 under 1k Hz.Secondly,in order to improve the dielectric constant of BZT20 samples,B sites Nb⁵⁺ions and Cu²⁺ions are used to study the influence mechanism of B site ions doping on the dielectric constant and diffuse phase transition of BZT20,and the relationship between PNRs and diffuse phase transition is established.Based on the theory of Maxwell-Wagner interface polarization and IBLC model,the influence of semi-conducted grain to high dielectric constant is analyzed.By adjusting the preparation process and doping content,the dielectric constant of BZT20 sample is doubled(ε_RT=35675).Thirdly,in order to further reduce the dielectric loss of BZT20 and enhance the diffuse phase transition,A sites Bi³⁺ions,Li⁺ions and Ca²⁺ions are used to analyze the influence mechanism of oxygen vacancy defect and grain size on dielectric loss.The relationship of PNRs size with diffuse phase transition and temperature coefficient of capacitance is established.Through optimizing the preparation process and doping content,the dielectric loss is reduced by one order of magnitude.At the same time,a BZT20 material system satisfying the Y5V standard is obtained.Finally,in order to improve the dielectric properties of BZT20 synthetically,the two step sintering method is used to prepare A site Bi³⁺ions,B site Zn²⁺ions and Nb⁵⁺ions co-doped（1-x）BZT20-x Bi₂(Zn_2/3Nb_4/3)O₇ system to further optimize its structure and dielectric properties.And the BZT20 system with high dielectric constant is prepared.Under the condition of dielectric loss maintaining the same order（tanδ=0.05）,the dielectric constant of the material system which meets the Y5V standard is nearly doubled(ε_RT=32668),which promotes the miniaturization process of electronic components.In addition,the Ba_1-xSm_2x/3(Zr_0.15Ti_0.85)O₃ system is prepared by solid-state reaction method.The influence of Sm³⁺ions on PNRs size is studied.The relation between PNRs size and the property of energy storage is established.By adjusting the doping content,the Ba_0.997Sm_0.002Zr_0.15Ti_0.85O₃ with high energy storage density（W₁=1.15J/cm³）is obtained,which is nearly two times higher than Ba(Zr_0.15Ti_0.85)O₃（W₁=0.4J/cm³）samples and higher than that of other Ba Ti O₃ based materials.It is a potential high performance dielectric energy storage material with potential application prospects in the energy storage field.更多还原