臺灣博碩士論文加值系統

近年來資訊業及電子科技的發展迅速，記憶體成為今日科技不可或缺的重要部分，由於電阻式記憶體(RRAM)具有讀寫速度快、結構簡單、單元面積小、密度高、低電壓驅動、低耗電、高操作週期及非揮發性等優點，而且運作只需搭配一個電晶體形成1T1R的結構，所佔的體積小因此使得電阻轉換記憶體成為學界、業界研究的新目標，許多研究團隊競相投入研發，文獻日益增加，研究的材料也越來越廣泛，從最早的Pr1-xCaxMnO3 (PCMO)到其他的鈣鈦礦材料，以及單元氧化物。電阻式記憶體(RRAM)是利用脈衝電壓使薄膜改變電阻值，但由於電阻轉換效應的機制尚無定論，因此尋找出電阻轉換機制以及材料特性對於電阻轉換的影響都是研究的大方向。
本論文主要探討二氧化鋯(ZrO2)這種材料在電阻轉換上的現象，用電子槍蒸鍍方式鍍制兩種不同厚度的薄膜(30 nm)及(60 nm)，再用镍(Ni)和鈦(Ti)分別鍍製兩種不同的上電極，形成Ti/ZrO2/TaN和Ni/ZrO2/ TaN兩種不同的結構。隨後再改變不同的退火溫度300oC、400oC兩種溫度下熱處理五分鐘，藉由不同退火溫度改變其結晶性，進而探討其差異性。本文以 電流－電壓測量（I－V sweeping），觀察其電阻轉換行為，進而探討不同上電極和退火溫度對電阻特性的影響。結果發現藉由熱處理可以改善生成電壓(Forming Voltage)及操作電壓，並且以Ni/ZrO2(30 nm)/TaN退火400oC後有最好的電阻轉換特性。

In recent years, the rapid development of electronic technology. Memory to become an indispensable technology today, resistive random access memories (RRAM) have attracted much attention for their simple structure, low power consumption, high speed operation, and high density integration. These advantages makes several research groups are rushing to research and development.From the earliest PCMO to other perovskite materials, and unit oxides. Resistive RAM (RRAM) is the use of pulse voltage changes the film resistance .However, the mechanism of resistance switching effect conclusive yet, so find out the resistive switching mechanism and material properties for conversion of resistance are the general direction of research.
We discussion the resistive switching characteristics of ZrO2 RRAM. We used the Deal E-Gun to deposition of two different thickness film(30nm,60nm).Then we deposited Ni (Nickel) and Ti (Titanium) two different top electrodes formation of Ti/ZrO2/TaN and Ni/ZrO2/TaN two different structures. After, these device to do heat treatment at two temperatures(300oC,400oC) for five minutes, Change the crystallization by different annealing temperature, then to study their differences.
In this paper, we used current to voltage measurements (I-V sweeping), to observe the resistance switching behavior, and then discuss the different top electrode to resistance characteristics influence, and we find that the sample Ni/ZrO2(30 nm)/TaN with annealing 400oC device exhibits better resistive switching characteristics.

中文摘要..........................................................I
英文摘要..........................................................II
致謝.............................................................III
目錄.............................................................IV
表目錄............................................................VII
圖目錄............................................................VIII
第一章 前言
1-1 簡介…………………………………………………………………………………………………………..............1
1-2 研究動機…………………………………………………………………………………………………..............1
第二章 文獻回顧
2-1記憶體總類的介紹……………………………………………………………………………………..............2
2-1-1相變化記憶體（OUM－ovonic unified memory）………………….….........2
2-1-2 鐵電記憶體(FeRAM) …………………………………………………………………………............3
2-1-3 磁阻式記憶體（MRAM－magnetroresistive RAM）……………............3
2-1-4 電阻式記憶體(RRAM)……………………………………………………………………………...........4
2-2 電阻轉換現象…………………………………………………………………………………………….............4
2-2-1名詞解釋………………………………………………………………………………………………….............5
2-2-2 Current compliance(限制電流)…………………………………………………………..........5
2-2-3 unipolar 和bipolar 特性…………………………………………………………………............5
2-3 電阻式記憶體材料種類……………………………………………………………………………...........6
2-3-1 單元金屬氧化物……………………………………………………………………………………...........6
2-3-2鈣鈦礦(perovskite)結構……………………………………………………………………...........7
2-4傳導機制(Conduction mechanisms) ……………………………………………………… .......7
2-4-1蕭基發射（Schottky emission）………………………………………………………..........7
V
2-4-2 穿遂效應（Tunneling effect）………………………………………………………..........8
2-4-3 空間電荷限制電流（Space-charge-limited-current ,SCLC）…….... 8
2-4-4 普爾－法蘭克發射（Poole-Frenkel emission）……………………………....... 8
2-4-5 離子傳導（Ionic conduction）………………………………………………………….........9
2-4-6 本質傳導（Intrinsic conduction）…………………………………………………........9
2-4-7歐姆傳導(Ohmic conduction) …………………………………………………………….........9
2-5 電阻轉換效應機制(Resistive switching mechanisms) ………………………....9
2-5-1氧移動機制(Oxygen movement mechanism) …………………………………………......9
2-5-2燈絲理論(Filament model)...................................10
2-5-3電荷trapping和detrapping………………………………………………………………...........12
2-6 介電崩潰機制………………………………………………………………………………………………..........12
第三章 實驗流程
3-1實驗步驟名詞解釋……………………………………………………………………………………..........22
3-1-1 RCA…………………………………………………………………………………………………...........22
3-1-2溼式氧化(Wet oxidation) ………………………………………………………….......22
3-1-3雙電子鎗蒸鍍法(Dual E-Gun) ……………………………………………………………....23
3-1-4退火…………………………………………………………………………………………………………........23
3-2 試片製備……………………………………………………………………………………………………........23
3-2-1基板與底電極………………………………………………………………………………………….........23
3-2-2薄膜鍍製…………………………………………………………………………………………………..........23
3-2-3退火條件…………………………………………………………………………………………………..........24
3-2-4上電極鍍製……………………………………………………………………………………………….........24
3-3 薄膜量測……………………………………………………………………………………………………...........24
3-3-1電流-電壓量測（I-V curve）……………………………………………………………….......24
第四章 結果與討論
VI
4-1-1轉換電壓的比較……………………………………………………………………………………...........25
4-1-2厚度影響………………………………………………………………………………………………............25
4-1-3漏電流曲線分析……………………………………………………………………………………...........26
4-1-4電流對電壓(I-V sweeping)在各條件之綜合比較………………………………......26
第五章 結論
未來展望
參考文獻

[1] Sang H. Yoon and Dong-Joo Kim, "Effect of substrate on the preferred orientation of ZnO films by chemical solution deposition," Journal of Crystal Growth (2007).
[2] 葉林秀、李佳謀、徐明豐等。"磁阻式隨機存取記憶體技術的發展—現在與未來，"物理雙月刊 廿六卷四期 (2004)。
[3] W. Zhuang, W. Pan, B. D. Ulrich et al., "Novell Colossal Magnetoresistive thin film nonvolatile resistance random access memory (RRAM)," International Electron Devices 2002 Meeting, Technical Digest, 193 (2002).
[4] D. Hsu, J. G. Lin, and W. F. Wu, "Resistive switching effects in Nd0.7Ca0.3MnO3 manganite," Journal of Magnetism and Magnetic Materials (2007).
[5] D. S. Shang, L. D. Chen, Q. Wang et al., "Asymmetric fatigue and its endurance improvement in resistance switching of Ag-La0.7Ca0.3MnO3-Pt heterostructures," Journal of Physics D-Applied Physics 40 (17), 5373-5376 (2007).
[6] C. C. Lin, B. C. Tu, C. H. Lin et al., "Resistive switching mechanisms of V-doped SrZrO3 memory films," Ieee Electron Device Letters (2006).
[7] C. C. Lin, B. C. Tu, J. S. Yu et al., "Resistive switching properties of SrZrO3-based memory films," Japanese Journal of Applied Physics (2007).
[8] C. Y. Lin, C. Y. Wu, C. Hu et al., "Bistable resistive switching in Al2O3 memory thin films," Journal of the Electrochemical Society 154 (9), G189-G192 (2007).
[9] C. Rohde, B. J. Choi, D. S. Jeong, S. Choi, J. S. Zhao, C. S. Hwang, “Identification of a determining parameter for resistive switching of TiO2 thin films”Appl. Phys. Lett (2005).
[10] J. J. Yang, M. D. Pickett, X. M. Li, ”Memristive switching mechanism for metal/oxide/metal nanodevices," Nature Nanotechnology,vol.3, 2008.
[11] A. Sawa, T. Fujii, M. Kawasaki et al., "Hysteretic current-voltage characteristics and resistance switching at a rectifying Ti/Pr0.7Ca0.3MnO3 interface," Applied Physics Letters 85 (18),4073-4075 (2004).
[12] H. Sim, D. J. Seong, M. Chang et al., "Excellent Resistance Switching Characteristics of Pt/Single-crystal Nb-Doped SrTiO3," IEEE (2006).
[13] B. P. Andreasson, M. Janousch, U. Staub et al., "Resistive switching in Cr-doped SrTiO3: An X-ray absorption spectroscopy study," Materials Science and Engineering B-Solid State Materials for Advanced Technology 144 (1-3), (2007).
[14] C. Y. Liu, C. C. Chuang, J. S. Chen et al., "Memory effect of sol-gel derived V-doped SrZrO3 thin films," Thin Solid Films 494 (1-2), 287-290 (2006).
[15] R. Oligschlaeger, R. Waser, R. Meyer et al., "Resistive switching and data reliability of epitaxial (Ba,Sr)TiO3 thin films," Applied Physics Letters 88 (2006).
[16] D. Hsu, J. G. Lin, and W. F. Wu, "Resistive switch in geffects in Nd0.7Ca0.3MnO3 manganite," Journal of Magnetism and Magnetic Materials 310 (2), 978-980 (2007).
[17] D. S. Shang, L. D. Chen, Q. Wang et al., "Asymmetric fatigue and its endurance improvement in resistance switching of Ag-La0.7Ca0.3MnO3-Pt heterostructures," Journal of Physics D-Applied Physics 40 (17), 5373-5376 (2007).
[18] R. Waser, M. Aono, "Nanoionics-based resistive switching memories”,Nature Materials (2007).
[19] Y. Sato, K. Kinoshita, M. Aoki et al., "Consideration of switching mechanism of binary metal oxide resistive junctions using a thermal reaction model," Applied Physics Letters 90 (3) (2007).