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研究生: 顏俞申
Yen, Yu-Shen.
論文名稱: 鐵鉑薄膜之磁性質及其阻態變化之應用
Magnetic properties of FePt thin films and their applications for resistive switching
指導教授: 賴志煌
Lai, Chih-Huang
口試委員: 林克偉
Lin, Ko-Wei
甘炯耀
Gan, Jon-Yiew
學位類別: 碩士
Master
系所名稱: 工學院 - 材料科學工程學系
Materials Science and Engineering
論文出版年: 2017
畢業學年度: 105
語文別: 中文
論文頁數: 36
中文關鍵詞: 鐵鉑電場控制磁記憶體電阻式記憶體鈦酸鍶鐵白金
外文關鍵詞: E field control
相關次數: 點閱:4下載:0
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  • 本文透過調控快速真空退火製程,在矽/二氧化矽基板上使鐵鉑薄膜在2, 3, 4.5奈米的厚度下序化並達成(001)優選取向。並在矽/二氧化矽基板,以鐵鉑作為底電極下在4.5奈米鐵鉑達成垂直異向性,以提供異常霍爾量測上進行進一步的量測。
    元件製作上透過黃光微影製程製作了鐵鉑薄膜作為層霍爾十字,並以二氧化矽、氧化鎂/二氧化矽作為絕緣層的元件。透過氧化鎂/二氧化矽以及二氧化矽絕緣層作為施加電場的介電層,進行異常霍爾效應量測,發現異常霍爾電壓以及矯頑磁場並未隨施加電壓以及時間有顯著改變,推測可能原自於較厚的鐵鉑薄膜以及電場屏蔽效應的影響,造成電場效應不顯著。
    另一方面透過金屬遮罩製作的元件上,絕緣層使用鈦酸鍶作為絕緣層,並以鉑、鐵鉑作為底電極,鉑作為頂電極。發現了透過不同的形成過程(forming process)可以達到單極性(uni-polar)以及雙極性(bi-polar)的阻態變化行為,並在IV量測上看到類似鐵電特性的曲線,以供後續進一步的研究確定此類似鐵電的性質是否為真正的鐵電特性。


    The electric field control of magnetism has drawn a lot of attention due to the need of reducing writing current densities on MRAM devices.
    This thesis focus on tuning FePt for ordering and (001) preferred orientation. On Si / SiO¬2 ¬ substrates, we tune the rapid thermal annealing process and FePt composition and introduce FeOx as capping layer or underlayer. We obtain ordering in FePt films of thickness 2, 3, and 4.5 nm with (001) preferred orientation. The reduction of FeOx to Fe on rapid thermal annealing process promotes the diffusion of Fe and Pt atoms, which leads to a better (001) preferred orientation. The perpendicular anisotropy is suit for analogous Hall measurement, which is often needed after device patterning and further spin Hall angle measurement.
    FePt on Pt 5 nm electrode also achieve perpendicular anisotropy by inserting ultrathin SiO2 insertion layer. The insoluble SiO2 insertion layer will diffuse through gran boundaries of FePt during rapid thermal annealing process and also promote the diffusion of Fe and Pt atoms. That leads to a lower ordering temperature.
    The RRAM characteristic of SrTiO3 dielectric layer is also tested. With different forming process, SrTiO3 can achieve unipolar switching and bipolar switching. The ferroelectric like IV curves also been observed. Further examination is needed to ensure the properties of SrTiO3 is ferroelectric or not. The cycling test and retention test shows stable RRAM characteristic of SrTiO3.

    第 1 章 前言 1 第 2 章 背景 3 2.1.1鐵鉑的性質 3 圖 2 2鐵鉑在不同成分下的結構圖 4 2.1.2快速熱退火 4 2.1.3鐵鉑連續膜 5 2.1.4 SiO2插入層 6 2.2電場控制 6 2.3 RRAM 10 第 3 章 第三章 實驗設備與分析儀器 13 3.1高真空濺鍍系統 13 3.2 X-射線繞射分析 ( X-ray diffraction) 14 3.3原子力顯微鏡 ( Atomic Force Microscope ) 15 3.4震動樣品磁測儀 ( Vibrating Sample Magnetometer ) 16 3.5聚焦式極化磁光柯爾效應儀 ( Focused Polar magneto-optical Kerr effect ) 17 3.6 快速真空退火爐 (Rapid Thermal Annealing) 18 3.7 黃光微影製程 (Photolithography) 19 第 4 章 第四章 實驗結果與討論 20 4.1鐵鉑薄膜磁性質調控 4.1.1 快速真空退火溫度之影響 20 4.1.2 氧化鐵覆蓋層之影響 21 4.1.3 氧化鐵覆蓋層之退火溫度調控 21 4.1.4 電壓控制下的異常霍爾量測 23 4.1.5 鐵鉑薄膜厚度之降低 24 4.1.6鉑底電極 27 4.1.7 二氧化矽插入層 28 4.2鈦酸鍶的電阻轉變 30 4.2.1 鈦酸鍶的單極及雙極轉變 30 4.2.2鈦酸鍶的形成過程 31 4.2.3 鈦酸鍶的類鐵電行為 32 4.2.4 鈦酸鍶的循環測試及記憶測試 33

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