電阻式記憶體被認為是次世代記憶體中最有潛力一，其具有非揮發，極短的寫入與抹除時間，低電壓操作、等優良特性。因此近年來被廣泛的研究，但是其電阻切換機制，仍然沒有一套完整的理論。
因此本研究將針對電阻式記憶體的切換機制作探討，主要利用原子層沉積(ALD)的氧化鉿薄膜作為主動層，並利用Fast IV量測技術，給入一個三角波的正偏脈衝電壓，使電阻式記憶體進行Set過程，當隨著脈衝升壓的時間變長，Set電壓下降，將實驗數據分析，在時間無窮遠時，可以得到一個最小的Set電壓值，稱為Set臨界電壓。另外發現臨界電壓與溫度項無關，且符合Nernst equation。
另外對不同限流Forming的電阻式記憶體，萃取其臨界電壓，可以發現Forming限流與臨界電壓呈負線性相關，根據Nernst equation，發現參與Set反應的氧濃度，會隨Forming限流呈指數上升，其是因為在Forming過程中發生了連鎖反應。
本實驗除了對Set作探討，亦對Reset過程作研究。由於元件的結構為Ti/HfO2/TiN，所以RRAM的切換端可在Ti電極或是TiN電極，藉由Fast IV量測，可以得到時間-電壓-電流，可以求得Reset發生前所需要的能量，藉由不同的脈衝升壓速率，進而得到能量逸散速率，可以發現Ti電極操作端其能量逸散速率比TiN電極端操作的大，其是因為Ti電極散熱速率比TiN電極快，所以能將能量給更大面積的氧原子，使得在DC IV上，可以觀察Ti電極Reset過程有更劇烈的電阻上升速率。

Resistive Random Access Memory (RRAM) is considered as one of the most promising candidate for the next-generation memories due to their excellent properties such as nonvolatile property, fast operation speed, low operation voltage. Even though RRAM has been extensively studied in recent years, there is still no comprehensive theory to clarify the resistive switching mechanism. Therefore this study mainly focuses on the RRAM switching process to better reveal the characteristics involved in this relative blank area.
The active layer (hafnium oxide) of RRAM is deposited by Atomic Layer Deposition (ALD) with a thickness of 10nm. Fast IV test technique is applied to track the set process of RRAM devices using positive triangle wave pulse, from which we find that set voltage decreases with the increase of rising time of the applied pulse. By analyzing the experimental data, critical voltage is defined when the rising time is at infinity. Meanwhile we find that the critical voltage is not relevant to temperature but in accordance with the Nernst equation.
Besides RRAM electro-forming process is thoroughly investigated, from which we find the concentration of oxygen rises exponentially with the increase of forming compliance current. And chain reaction model is proposed to clarify this process.
In this study Reset process is also investigated in addition to the Set process. As the structure of the device is Ti/HfO2/TiN, the resistance switch will occur on Ti or TiN electrode. With help of Fast IV measurement, time-voltage-current relationship can be obtained, from which energy needed before reset can be calculated . What’s more we can find the energy dissipation rate of Ti electrode is higher than that of TiN, measured by vary ramp rate voltage pulse. And this results from faster thermal dissipation rate of Ti electrode, which in turn delivers energy to larger amount of oxygen ions with wider range. And this is also the reason of more drastic rising rate of resistance in reset process near Ti electrode.

目錄
致謝 i
中文摘要 ii
Abstract iii
目錄 v
圖片目錄 vi
表格目錄 viii
第一章 序論 1
1-1前言 1
1-2研究目的與動機 2
第二章 文獻回顧 3
2-1 記憶體簡介 3
2-1-1相變化記憶體(Phase Change RAM， PCRAM) 4
2-1-2 磁阻式記憶體(Magnetic RAM， MRAM) 5
2-1-3 電阻式記憶體(Resistance RAM， RRAM) 6
2-2電阻式記憶體材料 8
2-2-1高分子材料 8
2-2-2鈣鈦礦 8
2-2-3過渡金屬氧化物 10
2-3 絕緣體載子傳輸機制 10
2-3-1歐姆傳導(Ohmic Conduction) 11
2-3-2 蕭基發射(Schottky emission) 12
2-3-3普爾-法蘭克發射( Poole-Frenkel Emission ) 13
2-3-4跳躍傳導（Hopping Conduction） 14
2-3-5穿隧(Tunneling) 15
2-3-6 空間電荷限制電流(Space Charge Limit Current， SCLC) 16
第三章 實驗設備與原理 17
3-1半導體精準電性量測系統 17
第四章 實驗結果與討論 19
4-1 氧化鉿薄膜在不同溫度下萃取Set臨界電壓 19
4-1-1能斯特方程式(Nernst equation) 19
4-1-1 常溫下萃取氧化鉿薄膜Set臨界電壓 20
4-1-2氧化鉿薄膜在不同溫度下萃取Set臨界電壓 24
4-2 不同Forming限流氧化鉿薄膜萃取Set臨界電壓 32
4-3 切換端電極散熱速率影響Reset過程 40
第五章 結論 52
References 53

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