臺灣博碩士論文加值系統

在對於讀取寫入速度需求日益增加的未來，可變電阻式記憶體(Resistive random-access memory, RRAM)無疑是一個具有相當發展潛力的下一代記憶體選擇，RRAM具有相當優異的讀取寫入速度、極佳的讀寫壽命、低寫入電壓以及低能量耗損，並且其電極-絕緣層-電極簡單的的三明治結構，對其未來微縮化以及堆疊層數有很大的優勢。本研究使用物理化學性質相當穩定的二氧化鈦以及氧化鋅，嘗試使其形成複合薄膜並形成較多的氧空缺，用以探討此方法是否能增加其電阻轉換效應。
本研究使用旋轉塗佈法將醋酸鋅-異丙醇鈦塗佈於基板上，並分別改變退火溫度、混和比例、退火時間，分別使用SEM觀察薄膜表面及橫截面，並以AFM對其表面粗糙度以及黏滯力、硬度做比較，再使用EDS對膜面做表面元素分析後，在表面鍍上一層白金作為上電極，使用Probe Station量測其I-V曲線觀察其電阻轉換效應，最後取用各變因最佳之參數製成最終樣品。
由實驗結果得知，在相同條件下，不同的混和比例的確會造成不同程度的電阻轉換效應改變，而退火溫度以及退火時間影響的則是反應副產物殘留的多寡。在各項最佳參數的最終樣品中，其最高的電阻轉換開關比來到了2.8x103，相較於對照組ZnO提高了200倍；TiO2則是近千倍。而相較於文獻則是比ZnO高50倍，比TiO2高了10倍上下，可以說是相當顯著的提升。而使用XPS對其O1s鍵節能做分析，其氧空缺達到了約18%的高佔比，側面驗證了此方法的確可以增加氧空缺並增加電阻轉換效應。

In the future, as the demand for faster read and write speeds increases, Resistive Random-Access Memory (RRAM) undoubtedly emerges as a next-generation memory option with significant development potential. RRAM possesses excellent read and write speeds, outstanding read/write endurance, low write voltage, low energy consumption, and its electrode-insulator-electrode sandwich structure is simple, providing significant advantages for future miniaturization and stacking. This study utilizes titanium dioxide (TiO2) and zinc oxide (ZnO), which exhibit stable physical and chemical properties, to form a composite thin film and generate more oxygen vacancies in order to investigate whether this method can enhance its resistive switching effect.
The study employs the spin-coating method to coat zinc acetate and isopropyl alcohol on a substrate, with varying annealing temperature, mixing ratio, and annealing time. The surfaces and cross-sections of the films are observed using scanning electron microscopy (SEM), while atomic force microscopy (AFM) is used to compare surface roughness, viscosity, and hardness. Energy-dispersive X-ray spectroscopy (EDS) is used to analyze the surface elements of the films, followed by the deposition of a platinum layer as the top electrode. The resistive switching effect is observed by measuring the I-V curves using a probe station. Finally, the optimal parameters for each variable are selected to fabricate the final samples.
Based on the experimental results, it is observed that different mixing ratios indeed lead to varying degrees of resistive switching effect under the same conditions, while annealing temperature and time influence the amount of residual reaction by-products. Among the final samples with the best parameters, the highest resistive switching ratio reaches 2.8x10³, which is 200 times higher compared to the control group (ZnO), and nearly a thousand times higher compared to TiO2. It represents a significant improvement, around 50 times higher than ZnO and approximately 10 times higher than TiO2, as reported in the literature. X-ray photoelectron spectroscopy (XPS) analysis of the O1s energy reveals an oxygen vacancy proportion of approximately 18%, providing additional evidence that this method can indeed increase oxygen vacancies and enhance the resistive switching effect.

摘要 i
Abstract ii
目錄 iii
圖表目錄 vi
第一章 介紹 1
1.1 前言 1
1.1.1 鐵電隨機存儲記憶體(Ferroelectric Random Access Memory ,FeRAM) 2
1.1.2 相變化存儲記憶體(Phase-change Memory ,PCM) 2
1.1.3 磁阻式隨機存儲記憶體(Magnetoresistive Random Access Memory ,MRAM) 2
1.1.4 可變電阻式隨機存儲記憶體(Resistive random-access memory, RRAM) 3
1.2 可變電阻材料 3
1.2.1 燈絲理論(Filament Theory) 4
1.2.2 可變電阻轉換特性 5
1.2.2.1 單極性(Unipolor) 5
1.2.2.2 雙極性(Bipolor) 5
1.2.3 薄膜傳導機制 6
1.2.3.1 歐姆傳導(Ohmic Conduction) 6
1.2.3.2 蕭基發射(Schottky Emission) 6
1.2.3.3 法蘭克-普爾發射(Frenkel-Poole Emission) 7
1.2.3.4 跳躍傳導(Hopping Conduction) 8
1.2.3.5 穿隧傳導(Tunneling) 8
1.2.3.6 空間限制電流傳導(Space Charge Limited Conduction,SCLC) 9
1.3 二氧化鈦及氧化鋅 9
1.3.1 二氧化鈦(Titanium Dioxide,TiO2) 9
1.3.2 氧化鋅(Znic Oxide,ZnO) 10
1.4 研究動機及文獻回顧 10
第二章 儀器介紹與工作原理 12
2.1 旋轉塗佈機(Spin coater) 12
2.2 電磁加熱攪拌器(Hot plate/magnetic stirrer) 12
2.3 掃描式電子顯微鏡(Scanning Electron Microscope, SEM) 13
2.3.1 掃描式電子顯微鏡之光學系統 13
2.3.2 電子槍(electron gun) 14
2.3.3 電磁透鏡(condenser lens) 15
2.3.4 掃描式電子顯微鏡之偵測訊號 17
2.4 X光能量散佈分析儀(Energy Dispersive X-ray Spectrometer,EDS) 19
2.4.1 EDS儀器介紹 19
2.4.2 工作原理及架構 20
2.5 原子力顯微鏡(Atomic force Microscope,AFM) 20
2.5.1 儀器原理 20
2.5.2 儀器架構 22
2.6 X光粉末繞射儀(X-ray Power Diffraction, XRD) 23
2.6.1 儀器原理 23
2.6.2 低掠角X光繞射法 23
2.6.3 定性與定量分析 24
2.7 X光電子能譜儀(X-ray Photoelectron Spectroscopy, XPS) 24
2.7.1 儀器原理 24
2.7.2 儀器架構 25
2.8 電性量測系統(Probe station) 25
第三章 實驗試劑、方法與元件製備 26
3.1 實驗試劑 26
3.2 實驗方法與元件製備 27
3.2.1 配製醋酸鋅-異丙醇鈦溶液 27
3.2.2 薄膜與電性量測樣品製備 27
第四章 結果與討論 28
4.1 不同退火溫度對TiO2摻雜ZnO薄膜的影響 28
4.1.1 SEM表面以及橫截面外觀變化 28
4.1.2 EDS元素分析 30
4.1.3 AFM表面分析 30
4.1.4 I-V量測 33
4.2 不同摻雜比例對氧化鋅-二氧化鈦薄膜的影響 34
4.3 退火時間對氧化鋅-二氧化鈦薄膜的影響 38
4.3.1 表面及橫截面外觀變化 38
4.3.2 EDS元素分析 39
4.3.3 I-V量測 40
4.4 500℃退火溫度、20%摻雜濃度、3小時退火時間 42
4.4.1 C-AFM電流分佈 42
4.4.2 XPS 元素鍵結分析 43
4.4.3 I-V 量測 44
4.5 Potential diagram 44
第五章 結論 45
第六章 參考資料 46

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