Studies of physical properties in BiFeO3 thin films 楊順得、NOTE
E-mail: [email protected]
ABSTRACT
BiFeO3(BFO) thin films were grown by radio frequency(RF) magnetron sputter deposition on a (111) SrTiO3(STO) substrate., These films were grown with Fe:Bi ratio =1:1.02 of target,, and at different argon environmental pressures and different growth time to grow, the growth of pressure used in the experiments were 20 × 10-2 torr. and 60 × 10-2 torr., the substrate temperature of 600
℃ under the growth of this film. By X-ray diffraction for analysis, observed perpendicular to the films surface of the X-ray
diffraction, showing the BFO thin film of STO (111) epitaxial properties , BFO lattice parameter matching (111) peak, the diffraction peak of the angle is 40 °, the growth of the BFO film with time will affect the structure, the growth in the relatively long time under the BFO thin film structure will be more obvious, the film growth will significantly affect the pressure structural phase BFO with the mixed phase (Bi25FeO40 , Bi2Fe4O9), the growth in the low pressure of the growth of the BFO film with the structure will be better, and also in the mixed phase is relatively good improvement on the film surface analysis using atomic force microscope (AFM) and scanning electron microscopy (SEM) to do measurements, we found that crystallization and surface roughness at a relatively low under the pressure of growth are more favorable, and in the electrical aspects of the I-V curves show only films with Ohmic nature of the relationship, the other part of the activation energy of the film in a relatively high growth under the pressure of a relatively high activation energy. Keywords: magnetron sputter, epitaxial, atomic force (AFM ), scanning electron microscope ( SEM)
Keywords : magnetron sputter、epitaxial、atomic force (AFM )、scanning electron microscope ( SEM) Table of Contents
中文摘要．．．．．．．．．．．．．．．．．．．．．．．．iii 英文摘要．．．．．．．．．．．．．．．．．．．．
．．．．iv 誌謝．．．．．．．．．．．．．．．．．．．．．．．．．．v 目錄．．．．．．．．．．．．．．．．．
．．．．．．．．．vi 圖目錄．．．．．．．．．．．．．．．．．．．．．．．．．ix 表目錄．．．．．．．．．．．
．．．．．．．．．．．．．．xii 第一章 導論 ．．．．．．．．．．．．．．．．．．．．．．1 1.1 前言．．．．．．
．．．．．．．．．．．．．．1 1.2 研究動機．．．．．．．．．．．．．．．．．．3 第二章 相關文獻 ．．．．．．
．．．．．．．．．．．．．．4 2.1 鐵電材料簡介 ．．．．．．．．．．．．．．．．4 2.1.1 鐵電材料結構特性．．．
．．．．．．．．．．4 2.1.2 鐵電材料介電與電滯曲線．．．．．．．．．．9 2.2 磁性質簡介．．．．．．．．．．．．
．．．．．13 2.2.1 磁性原理及介紹 ．．．．．．．．．．．．．13 2.2.2 磁滯曲線．．．．．．．．．．．．．．．．17 2.3 電性質簡介．．．．．．．．．．．．．．．．．18 2.3.1 極化機制以及頻率特性．．．．．．．．．．18 2.3.2 漏電 流機制．．．．．．．．．．．．．．．21 2.4 BiFeO3簡介 ．．．．．．．．．．．．．．．．24 2.4.1 晶體結構．．．
．．．．．．．．．．．．．24 2.4.2 BFO電性質．．．．．．．．．．．．．．．28 2.4.3 BFO磁性質．．．．．．．．
．．．．．．．29 第三章 實驗流程介紹．．．．．．．．．．．．．．．．．．31 3.1 實驗材料．．．．．．．．．．．
．．．．．．．31 3.1.1 製作（BiFeO3）靶材藥品．．．．．．．．．31 3.1.2 實驗相關藥品及工具．．．．．．．．．．
．32 3.2 實驗設備．．．．．．．．．．．．．．．．．．33 3.2.1 陶瓷靶材製程設備．．．．．．．．．．．．33 3.2.2 射頻磁控濺鍍系統．．．．．．．．．．．．34 3.3 實驗流程．．．．．．．．．．．．．．．．．．35 3.3.1 靶材製備．
．．．．．．．．．．．．．．．35 3.3.2 基板清洗步驟．．．．．．．．．．．．．．38 3.3.3 BiFeO3薄膜分析．．．．
．．．．．．．．39 3.4 分析儀器 ．．．．．．．．．．．．．．．．．．41 3.4.1 X-ray繞射儀．．．．．．．．．．．
．．．．41 3.4.2 掃描式電子顯微鏡 ．．．．．．．．．． ．43 3.4.3 薄膜厚度測量．．．．．．．．．．．．．．45 3.4.4 掃描式探針顯微鏡．．．．．．．．．．．．46 3.4.5 電流-電壓曲線量測．．．．．．．．．．．．47 第四章 結果 與討論．．．．．．．．．．．．．．．．．．．48 4.1 靶材製備與分析．．．．．．．．．．．．．．．48 4.2 薄膜晶 體結構與分析．．．．．．．．．．．．．51 4.2.1 不同薄膜厚度比較．．．．．．．．．．． 52 4.2.2 不同成長壓力比較
．．．．．．．．．．． 53 4.3 薄膜表面型態分析．．．．．．．．．．．．．．55 4.3.1 AFM表面檢測分析．．．．．
．．．．．． 56 4.3.2 FE-SEM 表面檢測分析．．．．．．．．．．58 4.4 電流-電壓（I-V）特性曲線．．．．．．．．．
．．65 4.5製程參數對溫度-電阻（R-T）特性關係影響．．．．67 第五章 結論．．．．．．．．．．．．．．．．．．．
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