嵌入奈米顆粒γ-APTES薄膜多層次電阻切換特性之研究

本論文主要在研究有機材料3-氨基丙基三乙氧基矽氧烷(γ-APTES)為基材作用層，嵌入奈米顆粒材料後之電阻式記憶體切換特性。我們研究多種奈米顆粒包含SiO2、TiO2、SiO2+ZnO、TiO2+ZnO混合 γ-APTES 材料，以FTO玻璃當作底電極，Al則當作頂電極，使用半導體參數分析儀Agilent-4156B量測I-V電流-電壓特性曲線，探討在混合各種不同奈米顆粒複合有機材料之電阻式記憶體切換特性與各切換模態電阻累積分佈，並觀察UV光對I-V電流-電壓曲線的影響。我們發現以γ-APTES基材為作用層元件皆表現多層次電阻態的切換特性，混合SiO2與TiO2單一種奈米顆粒，可改善部分元件的切換特性，其中以混合SiO2 奈米顆粒的作用層在部分的元件中高低電阻態相差達7個數量級，然而混合多種奈米顆粒反而會使電阻切換特性變差，UV光也沒有明顯作用。利用燈絲理論為基礎的模型可以將實驗結果解釋得很好。在實驗中我們發現大部分的元件經過多層次電阻切換的操作後皆趨於高電阻模態無法再切換，我們猜測是導通的電流產生退火效應將導通的燈絲路徑阻斷。我們相信多層次電阻切換特性主要源於γ-APTES富含氧空缺的材料結構，而適量的SiO2 奈米顆粒可以提供鍵結減少氧空缺的數量，大幅提高高低電阻態差值，而電流熱效應會破壞氧空缺形成的路徑使元件停留在高阻態。另外我們分析所有元件的各層次的模態電阻值累積分佈，發現並沒有非常明確的不連續分佈現象，這個結果似乎顯示目前我們尚無法找出適當的製程，製作一致性燈絲分佈的γ-APTES基材作用層。

關鍵字

多層次；電阻式記憶體； 3-氨基丙基三乙氧基矽氧烷；奈米顆粒

並列摘要

The master thesis aimed to study the resistance switching characteristics of memristor using nanoparticle-embedded γ-APTES as active layer. Effects of adding individually one type of nanoparticles, or simultaneously two types of nanoparticles including SiO2, TiO2, SiO2+ZnO and TiO2+ZnO were investigated. Al as top gate and FTO glass as bottom gate were used for conducting electrodes for all the memristors. Current-voltage measurements and cumulative distribution of resistance state values analyses were made on the devices utilizing an Agilent 4156B. The UV light effects on the IV characteristics were also evaluated. Experimental results showed that by embedding different nanoparticles (SiO2, TiO2) individually into γ-APTES, all the memristors exhibited multi-level resistive switching behaviors and the switching characteristics were improved for some of the devices. With SiO2 nanoparticles embedded in the porous network structure of γ-APTES, 7 orders of magnitude of ratio of the high resistance and low resistance states was observed in some memristors. However, poor resistive switching properties were obtained in the devices with simultaneously adding two types of nanoparticles (SiO2+ZnO, TiO2+ZnO). The illumination of UV light has no effects on the improvement of resistance switching. A model of multi-level resistive switching based on filament theories can well explain our experimental results. After multi-level switching operations, we found that most of the devices tended to be in the high resistance state, and were not able to switch back to the low resistance level. It was believed that the multi-level resistive switching behaviors were attributed to the oxygen vacancy rich γ-APTES material, and the amount of SiO2 nanoparticles could provide chemical bonding with γ-APTES to reduce the number of oxygen vacancy, resulting in a substantial increase in the level difference between high and low resistance states. The current thermal effect during switching operation might destroy the conducting path formed by the oxygen vacancy, and the devices retained the high-resistance state. We also analyzed the cumulative distribution of the resistance values at all level states of the memristors. The results showed that the values of the resistance state distribution were not discrete. It seems that we are not yet able to find the suitable process for the fabrication of the γ-APTES-based active layer with a consistent filaments distribution.