摘要
　　利用化學溶液鍍著法生長Bi3.5Nd0.5Ti3O12 (BNT)及Bi3.25La0.75Ti3O12 (BLT)，探討摻雜Cr及Nb對其微結構及鐵電性質的影響。在摻雜Cr 的BNT (BNTCx) 及BLT (BLTCx)中，Cr陽離子以Cr3+ 及Cr6+ 的形式取代Ti4+ 的位置，其中以Cr6+ 為多數。摻雜Cr3+ 及Cr6+ 會分別減少及增加BNTCx和BLTCx的殘餘極化值 (2Pr)，此外摻雜Cr會使得晶粒大小減小及促進C軸成長傾向，造成2Pr 的下降。在本實驗中BNTCx及BLTCx的2Pr隨著Cr添加量的增加而減少，顯示出Cr3+ 的取代，晶粒大小的減小及C軸成長效應三個因素大於Cr6+ 取代所造成氧空缺減少的效應。摻雜Nb在BNTNx薄膜中，當x=0到x=0.005，2Pr值會從40µC/cm2 增加到43µC/cm2，然後再隨著Nb添加量的增加而減少。在BNTNx薄膜中，Nb陽離子以Nb5+ 取代Ti4+ 的位置可以減少氧空缺，增加2Pr值。BNTNx 2Pr 值的變化可看成是(1)減少氧空缺、(2)晶粒大小的減少兩種效應相互競爭的結果。

Abstract
　　The Cr and Nb doping on the microstructure and ferroelectricity of Bi3.5Nd0.5Ti3O12 (BNT) and Bi3.25La0.75Ti3O12 (BLT) films deposited by chemical-solution method were studied, respectively. For the Cr-doped BNT (BNTCx) and Cr-doped BLT (BLTCx) films the Cr cations substitutionally incorporated into the Ti4+ site were in the states of Cr3+ and Cr6+ with the amount of Cr6+ being dominant over that of Cr3+. The presence of Cr3+ and Cr6+ would degrade and improve the remanent polarization (2Pr) of BNTCx and BLTCx films, respectively. In addition, Cr doping induced a reduction in the grain size and c-axis oriented growth, resulting in the degradation of the 2Pr of BNTCx films as well. In the present study, the 2Pr of BNTCx and BLTCx films decreased with the Cr concentration (x) in the range of 0.01-0.1, revealing that the effects of Cr3+ doping, reduction of the grain size, and c-axis oriented growth are dominant over that of reduction of oxygen vacancies due to Cr6+ doping. For the Nb-doped BNT (BNTNx) films the 2Pr first increased from 40µC/cm2 at x=0 to 43µC/cm2 at x=0.005 and then decreased with increasing the Nb concentration (x) in the range of 0.01-0.1. In the BNTNx films the Nb cations substitutionally incorporated into the Ti site were in the state of Nb5+, which can reduce the amount of oxygen vacancies and thus improve the 2Pr. The variation of 2Pr with the Nb concentration (x) in the BNTNx films can be ascribed to the competition between the two effects, i.e., reduction of oxygen vacancies and reduction of grain size, induced by Nb doping.

本 文 目 錄

中文摘要……………………………………………………Ⅰ
英文摘要……………………………………………………Ⅱ
誌謝感言……………………………………………………Ⅲ
本文目錄……………………………………………………Ⅳ
表目錄………………………………………………………Ⅵ
圖目錄………………………………………………………Ⅵ

本文
第一章 簡介…………………………………………………1
1.前言………………………………………………………1
1.電子記憶體………………………………………………1
2.鐵電材料 ..………………………………………………1
2.記憶元件 ..………………………………………………3
第二章 基本理論……………………………………………6
1. 文獻回顧…………………………………………………6
1-1 PZT鐵電薄膜………………………………………6
1-2 SBT鐵電薄膜………………………………………7
1-3 BTO與BLT鐵電薄膜………………………………7
1-4 BNT鐵電薄膜………………………………………8
1-5 添加Bi2O3做為緩衝層……………………………9
1-6 添加高價陽離子在鐵電薄膜中……………………9
2.極化原理…………………………………………………10
3. 脈衝極化及疲勞量測原理………………………………11
4. 疲勞特性……………………………………………12
5 Bi4-XLaXTi3O12（BLT）之基本結構……………………13
6.化學溶液鍍著法…………………………………………13
6-1配方溶液的調配………………………………………14
6-2薄膜披覆…………………………………………………14
6-3低溫焦化熱處理………………………………………15
6-4高溫結晶與緻密化熱處理……………………………15
7. 電子槍蒸鍍系統…………………………………………15
8. 拉塞福背向散射儀………………………………………16
9. 掠角X光繞射法…………………………………………18
10. 化學分析電子儀………………………………………19
11. 實驗研究動機—BLT和BNT系鐵電薄膜………………20
第三章 實驗步驟與方法……………………………………22
1.實驗流程圖………………………………………………22
2. 溶液的配製……………………………………………23
2-1 BLTC溶液配製…………………………………………23
2-2 BNTC及BNTN 溶液的配製………………………………23
3.基板（底電極）Pt/Ta/SiO2/Si製備…………………23
4.BLTC、BNTC和BNTN鐵電薄膜製備………………………24
5.薄膜退火 .………………………………………………24
6.上電極製作 ……………………………………………24
7.接觸退火 ………………………………………………25
8.鐵電性質量測與分析……………………………………25
8-1.結晶相鑑定……………………………………………25
8-2.成分分析………………………………………………25
8-3.薄膜厚度測定…………………………………………25
8-4.遲滯曲線、時效與疲勞量測…………………………25
8-5. SEM及TEM的觀察………………………………………26
8-6.漏電流量測……………………………………………26
8-7.介電常數量測…………………………………………26
8-8.價數測定………………………………………………26
第四章 結果與討論…………………………………………27
1. 退火製程對BLT及BNT C軸成長的影響………………27
2. 溶液濃度對BNT及BLT薄膜殘餘極化的影響…………28
3. 摻雜Cr對BNT薄膜鐵電性質的影響……………………29
4. 摻雜Nb對BNT薄膜鐵電性質的影響……………………31
5. 參雜Cr對BLT薄膜鐵電性質的影響……………………33
第五章 結論…………………………………………………35
參考文獻……………………………………………………37

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