钛酸铋钠铁电薄膜掺杂研究

毕业论文

题目Na0.5Bi0.5TiO3铁电

薄膜的掺杂改性研究

学院材料科学与工程

二〇一一年六月十日

摘要

我们采用化学溶液分解法制备了(Na0.7K0.2Li0.1)0.5Bi0.5TiO3前驱体溶液，并在LaNiO3/Si 和(Ba,Sr)(Ti,Mn)O3/Si两种衬底上分别制备了(Na0.7K0.2Li0.1)0.5Bi0.5TiO3薄膜。X－射线衍射图谱显示：(Na0.7K0.2Li0.1)0.5Bi0.5TiO3薄膜具有良好的结晶性，值得注意的是在(100)取向LaNiO3衬底上制备的(Na0.7K0.2Li0.1)0.5Bi0.5TiO3薄膜表现出了(100)择优取向。(Na0.7K0.2Li0.1)0.5Bi0.5TiO3薄膜的厚度大约为220～230nm。为了进行电学性能测试，我们分别制备了金属-铁电薄膜-绝缘体-硅和金属-铁电薄膜-金属结构。Au/ (Na0.7K0.2Li0.1)0.5Bi0.5TiO3/(Ba,Sr)(Ti,Mn)O3/Si/Au的电容－电压曲线是逆时针的，为极化型存储方式；在±15V的偏电压下，电容－电压曲线的记忆窗口最大，约为 3.97V。Au/(Na0.7K0.2Li0.1)0.5Bi0.5TiO3/LaNiO3结构的电容-电压曲线为典型的―蝴蝶‖形。(Na0.7K0.2Li0.1)0.5Bi0.5TiO3铁电薄膜在LaNiO3和(Ba,Sr)(Ti,Mn)O3衬底上的积累态介电常数分别为300和220。

关键词：化学溶液分解法；Na0.5Bi0.5TiO3掺杂；铁电薄膜；电学性能

ABSTRACT

We prepared the (Na0.7K0.2Li0.1)0.5Bi0.5TiO3 precursor solution by a chemical solution decomposition method and deposited (Na0.7K0.2Li0.1)0.5Bi0.5TiO3 films on LaNiO3/Si and (Ba,Sr)(Ti,Mn)O3/Si by spin-coating. The XRD patterns of (Na0.7K0.2Li0.1)0.5Bi0.5TiO3 on two substrates showed that (Na0.7K0.2Li0.1)0.5Bi0.5TiO3 films are crystalline. Note that (Na0.7K0.2Li0.1) Bi0.5TiO3 on (100)-LaNiO3 has preferred (100) orientation. The thicknesses of (Na0.7K0.2Li0.1) 0.5

Bi0.5TiO3 films are about 220～230nm. For electrical measurements, we prepared 0.5

metal-ferroelectric films-insulator-silicon and metal-ferroelectric-metal capacitors. The C-V curves of Au/(Na0.7K0.2Li0.1)0.5Bi0.5TiO3/(Ba,Sr)(Ti,Mn)O3/Si/Au exhibit anticlockwise direction, indicting the memory type is polarization. The maximum memory window is 3.97V when the sweeping voltage is ±15V. The C-V curves of (Na0.7K0.2Li0.1)0.5Bi0.5TiO3 on LaNiO3 have typical butterfly pattern. The dielectric constants of (Na0.7K0.2Li0.1)0.5Bi0.5TiO3on LaNiO3 and (Ba,Sr)(Ti,Mn)O3 at the accumulate states are 300 and 220, respectively.

Key words: Chemical solution decomposition; (Na0.7K0.2Li0.1)0.5Bi0.5TiO3; ferroelectric thin films;

electrical property

目录

摘要................................................................................................................................................. I ABSTRACT ................................................................................................................................... II 目录............................................................................................................................................... I II 1前言. (1)

1.1 研究背景 (1)

1.2 铁电材料 (1)

1.3 钛酸铋钠 (5)

1.4 研究现状 (7)

1.5 研究内容及意义 (8)

2 实验原理与测试方法 (9)

2.1 薄膜制备技术 (9)

2.1.1 射频磁控溅射法 (9)

2.1.2 脉冲激光沉积 (9)

2.1.3 金属有机化合物气相沉积 (9)

2.1.4 溶胶-凝胶法(Sol-Gel) (10)

2.1.5 金属有机化合物分解法(MOD) (10)

2.1.6 金属有机化合物气相沉积法(MOCVD) (10)

2.2 化学溶液分解法(CSD) (11)

2.3 分析测试技术 (12)

2.3.1 X-射线衍射分析 (12)

2.3.2 电容-电压特性分析 (13)

2.3.3 介电性分析 (15)

3 (Na0.7K0.2Li0.1)0.5Bi0.5TiO3薄膜的制备及测试方法 (16)

3.1 实验原料及设备 (16)

3.1.1 实验原料 (16)

3.1.2 主要仪器设备 (16)

3.2 前驱体溶液的配制 (16)

3.3 薄膜的制备 (17)

3.3.1 清洗硅片 (18)

3.3.2 旋涂法制膜 (18)

3.4 电容结构的制备 (20)

4 (Na0.7K0.2Li0.1)0.5Bi0.5TiO3薄膜的结构及电学性质的研究 (21)

4.1 (Na0.7K0.2Li0.1)0.5Bi0.5TiO3的粉末的红外光谱图 (21)

4.2 衬底和(Na0.7K0.2Li0.1)0.5Bi0.5TiO3的XRD图 (22)

4.2.1 衬底的XRD图 (22)

4.2.2 (Na0.7K0.2Li0.1)0.5Bi0.5TiO3的结晶性 (23)

4.3 (Na0.7K0.2Li0.1)0.5Bi0.5TiO3的C-V特性曲线 (25)

4.3.1 (Na0.7K0.2Li0.1)0.5Bi0.5TiO3/(Ba,Sr)(Ti,Mn)O3/Si的C-V特性曲线 (25)

4.3.2 (Na0.7K0.2Li0.1)0.5Bi0.5TiO3/LaNiO3的C-V (26)

4.4 (Na0.7K0.2Li0.1)0.5Bi0.5TiO3薄膜厚度的测量 (29)

4.5 (Na0.7K0.2Li0.1)0.5Bi0.5TiO3的介电性能 (30)

5 结论 (33)