论文总字数：17046字

摘 要

随着计算机技术的加速发展，铁电材料在存储领域的优势日渐凸显，包括有源相控阵雷达在我国歼十战斗机中的应用，铁电材料在民用和军用领域的研究已经成为热点之一。

在最新一代非挥发性铁电存储器中，使用最多的铁电材料是Pb(Zr_xTi_1-x)O₃(PZT)和SrBi₂Ta₂O₉（SBT），但是前者由于含有铅，对人体和环境污染较大并且抗疲劳特性较差，因此对PZT的研究逐渐变少，而SBT陶瓷薄膜的制备温度偏高，通常高达750~850℃，并且剩余极化强度Pr较小，通常为4~16μC/cm²，这也成为制约SBT发展的最主要的短板。一般情况下，可以通过在制备的材料中掺杂其他元素，比如稀土金属元素，使得铁电材料的剩余极化提高、矫顽力场降低，从而使得铁电性能得到优化提高。

本论文以氧化钽为钽源，采用最为常见的溶胶- 凝胶法，制备合成了SrBi₂Ta₂O₉(SBT)、Pr_0.2Sr_0.8Bi₂Ta₂O₉(SPBT) 陶瓷薄膜粉体。采用X射线衍射仪，对所研究的SBT和SPBT进行晶相结构的结构表征。采用铁电测试仪对SBT和SPBT的铁电性能进行了测试分析，研究掺杂前后的变化。

实验结果表明：Pr³ 离子的掺杂并未能改变SBT陶瓷粉体的晶相结构，但是通过测量发现，掺杂会使得SBT 的介电常数增大。 实验结果同时发现，掺杂Pr³ 后，SBT 铁电陶瓷薄膜的铁电性能有了显著的提升，具体表现在剩余计划Pr增大，矫顽电场Ec降低。

关键词：铁电薄膜 钽酸锶铋 剩余极化 电滞回线

ABSTRACT

With the rapid development of computer technology, the advantages of ferroelectric materials in the field of storage has become increasingly prominent, including the use of active phased array radar in China J-10 fighter aircraft, ferroelectric materials in the field of civil and military research has become one of the hot spots.

In the latest generation of nonvolatile ferroelectric memory, the most widely used ferroelectric materials are Pb (Zr_xTi_1-x) O₃ (PZT) and SrBi₂Ta₂O₉ (SBT), but the former because of lead, the human body and the environment pollution and anti- The SBT ceramic film is prepared at a high temperature, usually up to 750 to 850 °C, and the residual polarization intensity Pr is small, usually 4 to 16 μC / cm², which becomes Constraints on SBT development of the most important short board. Doping modification study refers to the SBT as the representative of the bismuth layer structure of ferroelectric materials, adding some additional impurities, usually rare earth elements, so that the material's ferroelectric properties are improved. Under normal circumstances, through the doping modification, can improve the residual polarization Pr, reduce the coercivity field Ec, thus optimizing the bismuth layer ferroelectric material ferroelectric properties.

In this paper, SrBi₂Ta₂O₉ (SBT) and Pr_0.2Sr_0.8Bi₂Ta₂O₉ (SPBT) ceramic thin films were prepared by the most common sol-gel method using tantalum oxide as tantalum source. The structure and characterization of SBT and SPBT powders were characterized by XRD and XRD. The dielectric properties and ferroelectric properties were analyzed.

The experimental results show that the doping of Pr³ does not change the crystal

structure of SBT ceramic powder, but it is found that the dielectric constant of SBT increases with the measurement. However, as the test frequency increases, the dielectric constant still shows a decreasing trend. The experimental results also show that the ferroelectric properties of SBT ferroelectric ceramics have been improved remarkably after Pr³ doping, and the residual Pr is increased and the coercive electric field is reduced.

Key words: ferroelectric thin film; strontium tantalate bismuth; residual polarization; hysteresis loop

目 录

摘 要 I

ABSTRACT III

目 录 V

第一章 绪论 1

1.1铁电材料概述 1

1.1.1 铁电材料的研究背景 1

1.1.2 铁电材料的基本概念 1

1.1.3铁电材料的分类 3

1.1.4常见的铁电体结构 3

1.2 铁电薄膜概述 4

1.2.1铁电薄膜的定义与原理 4

1.2.2 薄膜材料的制备方法 5

1.3 国内外研究进展 7

1.3.1 掺杂La元素 7

1.3.2 PZT纳米粉作添加剂 8

1.3.3 掺杂Nb 元素 9

1.4 本论文需要解决的问题 10

1.4.1薄膜工艺问题 10

1.4.2基本物理问题 11

第二章 实验 13

2.1 铁电陶瓷薄膜的制备 13

2.1.1 实验主要试剂及仪器 13

2.1.2柠檬酸钽的制备 14

2.1.3 SBT 和 SPBT 粉体的制备 14

2.1.4 SBT和SPBT陶瓷的制备 14

2.1.5 SBT和SPBT陶瓷薄膜的制备流程图 14

2.2 SBT和SPBT陶瓷性能表征 16

2.2.1 X射线衍射分析 16

2.2.2 电滞回线的测量 17

3.1 氟化氢物质的量的确定 19

3.2 XRD衍射分析 19

3.3 SBT 和SPBT 的介电性能分析 20

3.4 SBT 和SPBT 的铁电性能分析 21

3.5 SBT 与SPBT 的漏电特性分析 22

3.6 实验结果对比分析 23

第四章 总结与展望 25

4.1总结 25

4.2展望 25

参考文献 26

致谢 28

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