本實驗主要對電阻式記憶體(Resistance Random Access Memory)在Reset部分進行物理機制研究。所使用元件為one transistor one RRAM (1T1R)元件。
當我們在進行RRAM (Resistance Random Access Memory)元件量測時，電性量測掃描的電壓間距的改變會影響RRAM的電性，我們使用1T1R元件進行Fast IV量測，給予三角脈衝，固定Reset 電壓與改變升壓速率，將量測到的電壓-電流轉換成能量與元件切換速度的關係，我們發現隨著切換能量的上升，元件切換速度也會隨之上升。從77K到350K的環境溫度改變之下，觀察到元件切換速度會與環境溫度成正相關。
利用Ohmic傳導機制對溫度的關係，計算出阻絲實際的工作溫度，進一步去驗證阻絲溫度高低。
為了使元件特性優化，我們探討LRS(Low resistance state) 與Reset電壓之關係，在Reset電壓與LRS阻值關係中，發現在中間阻值有異常的趨勢。在低阻值與高阻值下，會因為阻絲成長所排的氧離子多寡與距離主導Reset電壓大小。而在中間阻態的異常趨勢，是電流所造成之熱效應的影響範圍主導Reset電壓大小。
另外也探討Reset電壓與HRS(High resistance state) 之關係，在大Reset電壓下，會因為阻絲粗與氧離子被排到距離阻絲的遠近，影響可控制氧離子的多寡，使得HRS的不同。在小Reset電壓下，是因為阻絲細與可控的氧離子少，使得HRS阻值較低。而在中間Reset電壓，是因為電流熱效應所驅動氧離子數目的不同，使得HRS的不同。並計算在大Reset電壓下的能量，發現Reset電壓影響Reset所吸收能量大小進一步去影響到Roff大小。

In this study, we further research the switching mechanism during reset process in one-transistor-one-resistance random access memory (1T1R) devices.
When conducting RRAM measurement, step voltage has a great influence on I-V characteristics. In this thesis, fast-IV measurement has been applied on a 1T1R RRAM to explore relations between input energy and switching speed by use of applying fixed period triangle pulse with different rising time. Experiments results shows as increasing input energy, the resistance switching speed will increase at the same time. In addition, heat effect to RRAM switching speed was also investigated, which was seldom discussed in previous studies.
Environment factors in both high temperature (350K) and low temperature (77K) are investigated. We find the input energy easily dissipates in 77K temperature, making switching speed become slow. However, the input energy accumulates between conducting filament and electrode at 350K temperature, creating higher switching speed. Thus, the relation between input energy and switching speed has been proved. Moreover, we calculated the conduction filament temperature by the relationship between Ohmic conduction and temperature for verified the actual operating temperature during reset process.
In addition, we proposed a model to explain the relationship between low resistance state, LRS and reset voltage. In relatively low and high resistance, the reset voltage was dominated by the quantity and distance of oxygen ions which were generated while set process. Moreover, an abnormal trend between low resistance state, LRS and reset voltage were observed in relatively middle resistance. We found out the abnormal trend between LRS and reset voltage was dominated by current thermal effect.
Furthermore, the relationship between reset voltage and high resistance state (HRS) was further research. Under relatively high and low reset voltage, the resistance of HRS was dominated by the quantity and distance of controllable oxygen ions. On the other hand, the resistance of HRS was dominated by current thermal effect under relatively middle reset voltage.


Key words: Resistance Random Access Memory, Reset process, 1T1R, current thermal effect

論文審定書 i
摘要 ii
Abstract iii
目錄 v
圖目錄 viii
表目錄 xii
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 次世代非揮發性記憶體 3
2-1-1 鐵電式記憶體(FeRAM) 3
2-1-2 磁阻式記憶體(MRAM) 4
2-1-3 相變化記憶體(PCRAM) 5
2-1-4 電阻式記憶體(RRAM) 6
2-2 絕緣體載子傳導機制 8
2-2-1 歐姆傳導(Ohmic Conduction) 9
2-2-2 蕭基發射(Schottky Emission) 10
2-2-3 普爾-法蘭克發射(Poole-Frenkel Emission) 11
2-2-4 跳躍傳導(Hopping Conduction) 12
2-2-5 穿隧(Tunneling) 13
第三章 實驗設備 14
3-1 製程設備 14
3-1-1 多靶磁控濺鍍系統(Multi-Target Sputter) 14
3-2 電性量測設備 15
第四章 1T1R元件量測方法 17
4-1 1T1R元件 17
4-2 電性量測方式 17
第五章 Reset過程能量累積與溫度對電阻切換速度的影響 21
5-1 實驗動機 21
5-2 改變脈衝升壓速率對1T1R元件之影響 24
5-3 在不同溫度下改變脈衝升壓速率對1T1R元件之影響 31
第六章 利用電性量測方法萃取RRAM在操作時電阻絲的溫度 34
6-1 實驗動機 34
6-2 氧化鉿薄膜電阻式記憶體元件製作流程 34
6-3 利用歐姆傳導機制計算阻絲溫度 35
第七章 焦耳熱效應對Reset電壓與LRS的關係與分析 40
7-1 實驗動機 40
7-2 Reset電壓與LRS的關係 41
7-3 實驗結果與討論 45
第八章 焦耳熱效應對Reset電壓與HRS的關係與分析 50
8-1 實驗動機 50
8-2 Reset電壓與HRS的關係與分析 50
8-3 實驗結果與討論 52
第九章 Reset過成所吸收的能量對Reset電壓與HRS的關係與分析 57
9-1 實驗動機 57
9-2 Reset過成所吸收的能量對Reset電壓與HRS的關係與分析 57
9-3 實驗結果與討論 60
結論 62
參考文獻 64

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