本研究採用射頻磁控濺鍍製程，利用共鍍法(co-sputtering)將鉻摻雜氧化銦(Cr-doped In2O3, CIO)薄膜沈積於SiO2(100nm)/Si基板。腔體背景壓力約為3x10-7 Torr，薄膜成長壓力為5 x10-3 Torr，依據氧化銦、鉻靶材濺鍍功率不同，調控成長時間將薄膜厚度控制在100奈米(nm)。實驗分為兩部分：(1)氧化銦靶材濺鍍功率固定在25W，鉻濺鍍功率則分別為5、9、13W；(2)氧化銦靶材濺鍍功率固定在50 W，鉻濺鍍功率則分別為5、10、13 W。
由X光繞射結果得知，25W 濺鍍之CIO薄膜僅有微弱(222)繞射峰，意味結晶程度不佳。當濺鍍功率提升至50W，CIO薄膜則出現明顯之(222)、(400)與(440)繞射峰。但隨鉻濺鍍功率增加，繞射峰強度均隨之下降。利用高解析穿透式電子顯微鏡分析薄膜微結構，25W濺鍍之CIO薄膜幾乎為非晶結構，但50W濺鍍之CIO薄膜顯示底層非晶-上層結晶之類雙層結構，且非晶與結晶介面為鋸齒形狀。元素成份分析則顯示，25W濺鍍之CIO薄膜的Cr元素濃度由2.4%增加至6.2%；50W濺鍍之CIO薄膜，濃度由2.7%增加至4.7%。超導量子干涉儀磁性量測結果顯示，25W濺鍍之CIO薄膜其飽和磁化量並不隨摻雜Cr原子濃度增加而改變，維持約0.45 emu/c.c.；但50W濺鍍之CIO薄膜，隨Cr摻雜濃度增加而增大至1.78emu/c.c.。電子自旋共振之吸收譜強度變化則與量測之飽和磁化量變化一致，但所有薄膜均僅有單ㄧ吸收峰行為。
為研究雙層CIO薄膜所產生的鐵磁耦合來源，進一步分析薄膜內Cr元素之化學態，由電子能量損失譜結果得知， Cr離子在非晶區較結晶區有較高的氧化態。綜合以上所述，電子自旋共振能譜顯示僅有單一種氧化態Cr離子貢獻鐵磁耦合，但雙層結構CIO薄膜之結晶與非晶區卻具有不同氧化態Cr離子，推論其磁性耦合增強原因可能是Cr離子於結晶與非晶區化學態不平衡，導致電荷透過鋸齒狀界面轉移，轉移的電荷因庫侖排斥力使自旋同一方向，進而引致鐵磁性。

The study demonstrates that increasing ferromagnetic coupling can be achieved by doping dilute Cr ions in a zig-zag interface separated amorphous-crystalline bilayer indium oxide films . Saturation magnetization of bi-layered CIO films monotonically increases from ~0.27 to ~1.78 emu/c.c. with rising Cr doping concentration in contrast with a constant of ~0.45 emu/c.c. for pure amorphous films. Absorption intensity of electron spin resonance for bi-layered films also increases with rising Cr concentration, but almost unchanged for pure amorphous films. Chemical state analysis indicates that Cr ions are higher valence state in amorphous regions than in crystalline regions. The results suggest that doped Cr ions in amorphous and crystalline regions form different valence configurations, creating a charge reservoir which transfers electrons through zig-zag interfaces and in turn enhances ferromagnetism.

論文審定書........................................................................................................................i
誌謝...................................................................................................................................ii
摘要..................................................................................................................................iii
Abstract............................................................................................................................iv
目錄..................................................................................................................................vi
圖次.................................................................................................................................viii
第一章 緒論.................................................................................................................. 1
1-1 前言.......................................................................................................................... 1
1-2 稀磁性半導體發展之簡介......................................................................................... 2
1-3 文獻回顧................................................................................................................... 3
1-4 研究動機..................................................................................................................10
第二章 基礎原理..........................................................................................................11
2-1 氧化銦薄膜特性簡介............................................................................................11
2-2 磁性材料種類.......................................................................................................11
2-2-1 順磁性...........................................................................................................12
2-2-2 反磁性...........................................................................................................12
2-2-3 鐵磁性...........................................................................................................13
2-2-4 反鐵磁性.......................................................................................................13
2-3 鐵磁性來源...........................................................................................................14
2-3-1 RKKY理論模型.............................................................................................14
2-3-2束縛極化子模型.............................................................................................15
2-3-3 VRH同心圓模型............................................................................................16
第三章 實驗方法與儀器簡介........................................................................................18
3-1 射頻磁控濺鍍.......................................................................................................18
3-2 X-Ray繞射儀........................................................................................................19
3-3 電性量測性統.......................................................................................................20
3-4 穿透式電子顯微鏡................................................................................................21
3-5 超導量子干涉儀....................................................................................................22
3-6 電子順磁共振.......................................................................................................23
3-7 實驗流程..............................................................................................................24
第四章 實驗結果與討論...............................................................................................26
4-1 X-ray晶格繞射(XRD)結構分析............................................................................26
4-1-1不同濺鍍功率純氧化銦薄膜之晶格繞射分析..................................................26
4-1-2不同鉻原子濃度摻雜25、50W氧化銦薄膜之晶格繞射分析............................27
4-2 電子穿透式顯微鏡(TEM)微結構分析...................................................................29
4-2-1不同濺鍍功率純氧化銦薄膜之微結構分析.....................................................29
4-2-2不同鉻原子濃度摻雜25、50W氧化銦薄膜之微結構、元素分析....................30
4-3 電性分析.............................................................................................................31
4-3-1不同鉻原子濃度摻雜25W氧化銦薄膜之變溫電阻率、霍爾係數分析…..........31
4-3-2不同鉻原子濃度摻雜50W氧化銦薄膜之變溫電阻率、霍爾係數分析…..........32
4-4 超導量子干涉儀(SQUID)磁性分析......................................................................33
4-3-1不同鉻原子濃度摻雜25、50W氧化銦薄膜之磁化曲線分析............................33
4-5 電子損失能譜(EELS)化學組態分析.....................................................................36
4-4-1不同鉻原子濃度摻雜25、50W氧化銦薄膜之化學組態分析............................36
4-6 電子順磁共振(EPR)分析.....................................................................................40
4-5-1不同鉻原子濃度摻雜25、50W氧化銦薄膜之過渡元素分析............................40
4-7 鐵磁性起源之探討...............................................................................................43
第五章 結論.................................................................................................................46
參考文獻..........................................................................................................................48

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