本論文探討以具有垂直異向性之鈷鐵硼/氧化鎂作為自由層，量測不同尺寸元件之熱穩定性，及熱穩定量測之實驗架設。此外，製備出具較高熱穩定性之雙層鈷鐵硼結構試片。並進一步量測通入電流後因為Rashba效應和自旋霍爾效應產生的有效磁場以及臨界翻轉電流。
磁性質部分，藉由鈷鐵硼厚度的調整和退火條件達到最佳垂直異向性。接著鍍製雙層鈷鐵硼薄膜部分，藉由調控下層鈷鐵硼厚度和中間層鉭的鍍膜條件，得到MS*t上升較多，HK不會衰減的雙層膜結構。
微小化製程部分，藉由黃光微影製程和電子束微影製程搭配乾式蝕刻製作霍爾十字架結構，以異常霍爾效應得到霍爾電壓訊號藉以量測小尺寸元件之性質。
熱穩定性量測主要以脈衝磁場翻轉機率和動態矯頑場法為主，量測微米尺寸和奈米尺寸元件，並分析其中的關係。最後比較單層鈷鐵硼結構和雙層鈷鐵硼結構通入電流後產生的有效磁場和臨界翻轉電流。

This work has been focused on the deposition of perpendicular-anisotropy CoFeB/MgO free layer, measurement of thermal stability in different size devices, and the experimental setup of measuring thermal stability. Moreover, develop a new double CoFeB structure with higher thermal stability. Then, evaluate the effective field when a current passed and the threshold switching current density.
In the single CoFeB layer, I have tuned the thickness of CoFeB and the condition of annealing to get the better perpendicular anisotropy. After that, I have tuned the thickness of bottom CoFeB and sputter condition to get a double CoFeB structure with higher MS*t and a constant HK value.
In order to fabricate different size devices, I have used photolithography and E-beam lithography to pattern the Hall cross structure. I would like to use the Hall voltage which had been measured by AHE to investigate the properties of small-sized devices.
I mainly used pulse magnetic switching probability and dynamic coercivity method to measure the thermal stability of micro-sized and nano-sized devices. In the last part, I would like to compare the effective field and threshold switching current density between single CoFeB and double CoFeB structure.

致謝 i
中文摘要 ii
Abstract iii
目錄 iv
圖表目錄 v
第一章 前言 1
第二章 文獻回顧 2
2.1 穿隧磁阻現象 2
2.1.1 穿隧磁阻效應簡介 2
2.1.2 穿隧磁阻模型. 3
2.1.3 穿隧磁阻的實際應用. 7
2.1.4 交換偏壓自旋閥. 8
2.1.5 虛擬自旋閥. 9
2.2 電流感應磁矩翻轉現象 10
2.2.1 自旋轉移矩(spin-transfer torque)介紹. 10
2.2.2 Landau-Lifshitz-Gilbert(LLG) equation. 11
2.2.3 阻尼係數(damping constant)和動態磁矩翻轉. 12
2.2.4 磁穿隧結內的電流感應磁矩翻轉現象. 12
2.2.5 翻轉磁穿隧結之臨界電流密度. 14

2.3 鈷鐵硼/氧化鎂系統磁穿隧結之特性 16
2.3.1 氧化鎂作為絕緣層之穿隧機制. 16
2.3.2 鈷鐵硼/氧化鎂/鈷鐵硼磁穿隧結介紹. 17
2.3.3 鈷鐵硼之性質差異. 20
2.4 具垂直異向性之鈷鐵硼/氧化鎂磁穿隧結 22
2.5 雙層鈷鐵硼/氧化鎂結構 24
2.5.1 Co20Fe60Co20系統. 24
2.5.2 Co40Fe40Co20系統.. 25
2.6 異常霍爾效應(Anomalous Hall effect) 28
2.7 熱穩定性量測方法 29
2.7.1 等待時間法(waiting time method).. 29
2.7.2 動態矯頑場法(dynamic coercivity method).. 31
2.7.3 脈衝磁場翻轉機率法(pulse magnetic switching probability).. 32
2.8 電流生成自旋軌道矩(current-induced spin orbit torque) 34
2.8.1 Rashba 效應(Rashba effect).. 34
2.8.2 自旋霍爾效應(spin Hall effect).. 35
2.8.3 分析方法.. 37
第三章 實驗方法與分析儀器 39
3.1 實驗流程 39
3.2 樣品製備 39
3.2.1 薄膜沉積製程系統 39
3.2.2 退火系統 41
3.2.3 微影製程設備 41
3.2.4 電子束微影製程設備 42
3.2.5 蝕刻系統 43
3.3 量測分析儀器 44
3.3.1 原子力顯微鏡(AFM) 44
3.3.2 震動樣品磁測儀(VSM) 45
3.3.3 磁光柯爾效應分析儀(MOKE) 46
3.3.4 自製熱穩定性量測統 48
第四章 實驗結果與討論 51
4.1 磁性薄膜的製備 51
4.1.1 單層鈷鐵硼/氧化鎂系統 51
4.1.2 雙層鈷鐵硼/氧化鎂系統 54
4.2 微小化製程技術 67
4.2.1 黃光微影技術製備之微米尺寸元件 67
4.2.2 電子束微影技術製備之奈米尺寸元件 71
4.3 熱穩定性量測 72
4.3.1 微米尺寸元件之熱穩定性量測 72
4.3.2 奈米尺寸元件之熱穩定性量測 75
4.4 有效磁場量測 80
4.5 臨界翻轉電流量測 81
第五章 結論 85
參考文獻 86

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