臺灣博碩士論文加值系統

本論文主要探討穿隧式磁阻多層膜電磁特性之研究，運用磁控濺鍍系統製作磁性多層膜，探討鐵磁/反鐵磁系統中的交換偏壓耦合作用，改變不同薄膜厚度並比較其退火前後對多層膜磁特性的影響，並了解在不同溫度下之變化。並透過光微影術、離子蝕刻術來製作磁性穿隧結單元，了解蝕刻後樣品之表面型態，設法解決蝕刻所產生的反鍍現象，並量測其I-V曲線特性及磁阻，探究製程中可能造成元件損害的因素。
發現多層膜結構在室溫下能獲得最大的交換耦合偏壓場約180 Oe，在350 K時，亦能達到90 Oe。而本文利用特殊的蝕刻方式確實能改善蝕刻後樣品的表面型態，但在電性的表現上並不如預期，相信透過更大角度的斜向蝕刻方式，能對其表現大大改善。

This thesis mainly focuses on the research of the characteristics of tunneling magnetoresistance multiplayer. Through magnetron sputtering system to manufacture magnetic multilayer. we can probe into the exchange coupling phenomenon in ferromagnetic/antiferromagnetic system. In the meantime, by using sample with different thickness, we are able to compare the influences on magnetic property of multilayer before and after anneal, and get to know the changes under different temperatures.
Also, through photo-lithography and ion-milling to manufacture MTJ devices, to observe the surface texture and try to resolve the redeposition which is caused by etching process. By measuring the I-V characteristic and magnetoresistance, factors which cause device damages in the fabrication process can be found.
It was discovered that the largest exchange bias of the magnetic multilayer can reach is around 180 Oe at RT. It can also reach 90 Oe at 350K. In this thesis, it’s confirmed that the sample surface texture do get improved by using special etching method. However, it’s electric property will not be as good as expected. We believe the performance can be greatly improved by applying oblique etching method with wider angle.

第一章 緒論…………………………………………………………1
1-1前言……………………………………………………………1
1-2磁性的起源……………………………………………………1
1-3磁阻材料的發展與應用………………………………………3
第二章 理論及文獻探討………………………………………… 8
2-1前言……………………………………………………………8
2-2 交換磁異向性……………………………………………… 11
2-3 交換磁異向性相關模型………………………………………13
2-3-1 一般交換耦合模型……………………………………13
2-3-2 反鐵磁磁壁模型………………………………………16
2-3-3 無序場模型……………………………………………18
2-3-4 Spin-flop 正交界面耦合模型………………………21
2-3-5 Uncompensate界面模型探討…………………………23
2-4 Simmon’s 模型………………………………………………26
2-5 自旋相關穿隧效應……………………………………………32
2-6 Julliere's 模型…………………………………………… 35


第三章 實驗設備與實驗步驟……………………………………40
3-1 前言……………………………………………………………40
3-2 實驗設備………………………………………………………41
3-2-1鍍膜系統……………………………………………… 41
3-2-2離子束蝕刻系統……………………………………… 49
3-2-3超導量子干涉儀……………………………………… 51
3-2-4 原子力顯微鏡…………………………………………53
3-2-5 曝光機…………………………………………………55
3-2-6 掃描電子顯微鏡之應用………………………………57
3-3 樣品製程與量測………………………………………………60
3-3-1 樣品的清洗……………………………………………60
3-3-2樣品的製程…………………………………………… 61
3-3-2-1 交換耦合作用之磁性多層膜製作……………61
3-3-2-2 磁性穿隧結之蝕刻製程………………………62
3-3-3 樣品的量測……………………………………………68
3-3-3-1磁性多層膜交換場偏壓之量測………………68
3-3-3-2 磁性穿隧結之量測……………………………68


第四章 實驗結果與討論………………………………………… 70
4-1 前言……………………………………………………………70
4-2 交換耦合偏壓研究……………………………………………70
4-2-1 不同FeMn厚度……………………………………… 70
4-2-2 不同NiFe厚度……………………………………… 75
4-2-3 不同CoFe厚度……………………………………… 78
4-2-4 討論……………………………………………………81
4-2-5 交換場偏壓與溫度的關係……………………………84
4-3 自旋閥式MTJ蝕刻結果………………………………………85
4-3-1 蝕刻遮罩製作結果……………………………………85
4-3-2 60度側向蝕刻結果……………………………………86
4-3-3 樣品量測結果…………………………………………90
第五章 結論…………………………………………………………… 91
參考文獻……………………………………………………………… 93

【1-1】Lord Kelvin, Philosophic Magazine, (1857).
【1-2】M. N. Baibich, J. M. Broto, A. Fert, F. Nguyenvan Dau, F. Petroff, P. Etienne, G. Creuzet, A. Friederich and J. Chazelas, Phys. Rev. Lett. 61,2472 (1988).
【1-3】Moodera J S, Kinder L R, Wong T M and Meservey R, Phys. Rev. Lett. 74, 3273, (1995).
【1-4】Moodera J S and Mathon G, J. Magn. Magn. Mater. 200, 248, (1999).
【1-5】Parkin S S P et al, J. Appl. Phys. 85, 5828, (1999).
【1-6】de Boeck J and Borghs G, Phys. World 12, 27, (1999).
【1-7】Tehrani S et al, Proc. IEEE 91, 714, (2003).
【2-1】Jagadeesh S. Moodera and Lisa R. Kinder, 4724 J. Appl. Phys. 79 (8), (1996).
【2-2】X F Han Presented at the 8th International Conference on Electronic Materials (IUMRS-ICEM 2002, Xi’an, China, 10–14 June(2002)
【2-3】W. H. Meiklejohn and C. P. Bean, Phys. Rev. 102, 1413 (1956).
【2-4】W. H. Meiklejohn and C. P. Bean, Phys. Rev. 105, 904 (1957).
【2-5】J. Nogués and I. K. Schuller, J. Magn. Magn. Mater. 192, 203 (1999).
【2-6】Ph. Lambin, and F. Herman, Phys. Rev. B 30, 6903 (1984).
【2-7】R.D. Hempstead, S. Krongelb, and D.A. Thompson, IEEE Trans. Magn. 14, 521 (1978).
【2-8】D. Mauri, H.C. Siegmann, P.S. Bagus, and E. Kay, J. Appl. Phys. 62, 3047 (1987).
【2-9】Daniele Mauri, Eric Kay, David Scholl, and J. Kent Howard, J. Appl. Phys. 62, 2929 (1987).
【2-10】A. P. Malozemoff, Phys. Rev. B 35, 3679 (1987).
【2-11】N. C. Koon, Phys. Rev. Lett. 78, 4865 (1997).
【2-12】T. C. Schulthess and W. H. Butler, Phys. Rev. Lett. 81, 4516 (1998).
【2-13】T. C. Schulthess and W. H. Butler, J. Appl. Phys. 85, 5510 (1999).
【2-14】K. Takano, R.H. Kodama, and A.E. Berkowitz, Phys. Rev. Lett., 79, 1130 (1997)
【2-15】J. G. Simmon, J.Appl.Phys.,34 ,P1793 (1963).
【2-16】Tedrow P M and Meservey R, Phys.Rev.Lett, 26, 192 (1971).
【2-17】M.Julliere,Phys.Lett.54A,225(1975)
【2-18】Gary A. Prinz, SCIENCE, 282, (1998).
【2-19】Evgeny Y Tsymbal,Oleg N Mryasov and Patrick R LeClair J.Phys:Condens.Matter 15, R109-R142, (2003).
【3-1】李學丹、萬英超、姜祥祺、和杜元成，真空沈積技術，p65-114
【3-2】李秉傑，科儀新知，第十三卷第四期，p28(1992)
【3-3】Quantum Design，超導量子干涉儀操作手冊
【3-4】http://www.ndl.org.tw/icfab/chinese1/index.htm
【3-5】陳家全、李家維、和楊瑞森，生物電子顯微鏡學，p5-22,p112-131
【3-6】Michael E. Walsh thesis Master of Science in Electrical Engineering at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY August, 2000
【3-7】Robert E. Lee, J. Vac. Sci. Technol. 16(2), Mar. /Apr. 1979
【4-1】V. K. Sankaranarayanan, S. M. Yoon, D. Y. Kim, C. O. Kim, and C. G. Kim, JOURNAL OF APPLIED PHYSICS 96(12), 7428, 2004.
【4-2】C. Tsang, N. Heiman, and Kenneth Lee, JOURNAL OF APPLIED PHYSICS 52(3), 2471, 1981.