電阻式記憶體（Resistive Random Access Memory，ReRAM）是近年來被開發的新興記憶體，被期待能夠取代快閃記憶體。本研究成功製造了以TiN/TiOx/WOx/W為基本結構的燈絲型電阻式記憶體，並從兩個方向探討了電阻式記憶體的可靠度問題：成型溫度與上部電極材料。我們在TiN/TiOx/WOx/W元件上評估成型溫度與所需電壓之間的相關性，然後進行包括循環耐久性（Cycling endurance）和數據保持性（Data retention）的可靠度測試，最後提出了一個模型來解釋結果。
ReRAM的導電機制與上部電極和金屬氧化物層密切相關。我們接著用Pt代替TiN做為TiN / TiOx / WOx / W ReRAM元件的上部電極，以闡明頂部電極材料與可靠性之間的關係。我們進行了循環耐久性等可靠性試驗。對於TiOx / WOx RRAM，以Pt做為上部電極的元件相較於以TiN做為上部電極的元件而言具有更好的特性。耐久性已經成功地從100個週期增加到超過3000個週期，此外寫入電流也明顯被降低了。

In this study, we successfully fabricated the RRAM device with TiN/TiOx/WOx/W structure and explored the reliability issue in two directions：forming temperature and top electrode material. The forming voltage and temperature for creating the first filament in the RRAM device are found having impacts on RRAM reliability. The correlation between the forming temperature and the required voltage was evaluated on the TiN/TiOx/WOx/W RRAM devices, and then the reliability tests including cycling endurance and data retention were performed. Finally, A model was proposed to explain the results.
Moreover, the conduction mechanism of the RRAM is closely related to the top electrode and the metal oxide layer. The top electrode of the TiN/TiOx/WOx/W RRAM device was replaced by Pt to elucidate the relationship between top electrode material and the reliability. The reliability tests such as cycling endurance were performed. For TiOx/WOx RRAM, Pt top electrode devices exhibited better characteristic than TiN top electrode devices. The endurance has been increased successfully from 100 cycles to more than 3000 cycles, and the write current was also reduced.

摘要---------------------------------------------I
Abstract-----------------------------------------II
誌 謝--------------------------------------------III
Contents-----------------------------------------IV
List of Figures----------------------------------VI
List of tables-----------------------------------VIII
Chapter 1 Introduction---------------------------1
Chapter 2 Literature-----------------------------3
2-1 Introduction of memory-----------------------3
2-1.1 Volatile memory----------------------------3
2-1.2 Non-volatile memory------------------------4
2-2 Emerging non-volatile memory-----------------5
2-2.1 Ferroelectric RAM--------------------------5
2-2.2 Magnetic RAM-------------------------------6
2-2.3 Phase change RAM---------------------------7
2-2.4 Resistance RAM-----------------------------7
2-3 Resistance random-access memory--------------8
2-3.1 Material of resistance layer---------------8
2-3.2 Mechanism of resistance switching----------11
Chapter 3 Experiments and procedures-------------25
3-1 1Mb test chip fabrication--------------------25
3-2 Experiment procedure-------------------------27
3-2.1 Forming performance------------------------27
3-2.2 Reliability analysis-----------------------27
3-2.3 Top electrode effect-----------------------27
Chapter 4 Results and discussion-----------------33
4-1 ReRAM operation------------------------------33
4-1.1 Forming------------------------------------33
4-1.2 SET and RESET------------------------------34
4-2 Impact of high forming temperature-----------35
4-2.1 Forming voltage and performance------------35
4-2.2 Endurance----------------------------------37
4-2.3 Retention----------------------------------37
4-2.4 Model of filament--------------------------38
4-3 Impact of different top electrode------------39
4-3.1 Operation----------------------------------40
4-3.2 TiN top electrode--------------------------40
4-3.3 Pt top electrode---------------------------41
Chapter 5 Conclusion and Future work-------------52
5-1 Conclusion-----------------------------------52
5-2 Future work----------------------------------53
Reference----------------------------------------54

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