本論文中，主要以氧化鎵作為非揮發性電阻式記憶體的電阻轉換層，主要是因為鎵原子時常用來作為電晶體、感測器、太陽能電池的材料，且氧化鎵對氧濃度的改變也非常敏感，並探討不同上電極及氧空缺濃度對其電性的影響，且加入其他氧化鎵系列氧化物改善其記憶體特性。
首先，我們探討氧化鎵電阻式記憶體在金屬上電極為鋁、鈦及鉑，鉑作為下電極的情況下，不同氧空缺濃度對其造成的影響，為此，我們透過X射線光電子能譜(XPS)分析氧化鎵系列氧化物其中的氧空缺濃度，也以穿透式電子顯微鏡(TEM)分析不同上電極與電阻轉換層的介面，確認此介面對電阻式記憶體的電性影響。結果顯示這些製備完成的元件，在直流操作下，有著雙極性特性，其中，鋁電極記憶體開關比最大可達7個數量級，鈦電極記憶體有著超過300次電阻轉換次數的最佳耐久度，但開關比卻會逐漸退化，而鉑電極記憶體則有不超過100次的耐久度。另外這些元件在室溫、0.1伏特讀取電壓下，保持高低阻態各10k秒的穩定記憶能力。
此外，為得知氧空缺濃度梯度方向，我們製作兩種相反氧空缺濃度梯度方向之Al/ZnO/Ga2O3/Pt及Al/Ga2O3/ZnO/Pt 記憶體，發現Al/ZnO/Ga2O3/Pt在氧空缺濃度梯度的幫助下，得到更穩定、更耐久的電阻轉換特性，在雙極性的直流操作下，耐久度可超過4000次，並在室溫、0.1伏特讀取電壓下，保持高低阻態各10k秒的穩定記憶特性。
最後我們研究兩層間插入具有豐富氧空缺含量之氧化鋅鎵，提供氧空缺之外也減少氧空缺的移動距離，另外，也製作兩阻不同材料實現的氧空缺濃度梯度之電阻式記憶體作為比較，發現電阻轉換將因為氧空缺濃度梯度及較短距離的氧空缺移動而更易達成，元件表現更加穩定外，也得到更小的操作電壓，意味著不僅電極及電阻轉換層材料，有著氧空缺濃度梯度漸變及較短距離的氧空缺移動之電阻轉換層結構也是改善電阻式記憶體特性的重要方法之一。

In this thesis, Ga2O3 is mainly used as the switching layer of resistive non-volatile random-access memory. This is because gallium atoms are often used as materials of transistors, sensors, and solar cells. And gallium oxide is sensitive to the concentration change of oxide. So, we discuss the effects of different top electrodes and oxygen vacancy concentrations on its electrical properties, and other gallium oxide series oxides were added to improve its memory characteristics.
First, we investigate the effect of different oxygen vacancy concentration when the gallium oxide RRAM uses aluminum, titanium, and platinum as top electrode, platinum as bottom electrode. We analyze the oxygen vacancy concentration of gallium series oxide through XPS, and analyze the interface of the top electrode and RS layer through TEM to confirm the effect of this interface on the electrical properties of RRAM. The results indicate that under DC operation, the fabricated devices is at bipolar mode. Among them, the devices of aluminum TE have on/off ratio up to 7 orders. The devices of titanium TE have endurance more than 300 times, but there are gradual degradation on the on/off ratio. The devices of platinum TE have endurance less than 100 times. And all these devices, at room temperature, can maintain stable high resistance state (HRS) and low resistance state (LRS) respectively for 10k seconds at 0.1V reading voltage.
Then, to know the direction of the gradient of oxygen vacancy concentration, we fabricated two opposite directions of the gradient of oxygen vacancy concentration as Al/ZnO/Ga2O3/Pt and Al/Ga2O3/ZnO/Pt. It is found that Al/ZnO/Ga2O3/Pt performs more stable and enduring on the resistive switching property, and in bipolar mode, under DC operation, it has endurance more than 4000 times, and can maintain stable high resistance state (HRS) and low resistance state (LRS) respectively for 10k seconds at 0.1V reading voltage.
Finally, we investigate the effect of inserting zinc gallium oxide with enriched oxygen vacancies in the bilayer RRAM to shorten the oxygen vacancy migration distance. In addition, two resistive memories with oxygen vacancy concentration gradients realized by different materials were also fabricated for comparison. It is found that resistance switching will be more easily achieved due to oxygen vacancy concentration gradient and shorter distance of oxygen vacancy migration. The results indicate that not only electrode and RS layer materials, the structure with gradual oxygen vacancy concentration gradients and shorter distance oxygen vacancy migration is one of the methods to improve the performance of RRAM.

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