先進電阻式與鐵電式憶阻器元件

Abstract

本論文主要分為兩個大部分，第一部分探討電阻式憶阻器的製備與操作流程，我們藉由觀察結晶材料與非結晶材料的性質比較，發現利用結晶性材料的單層氧化物電阻式憶阻器，雖然需要較大的操作電壓，但是有較高的操作次數。為了降低操作電壓並且提升操作次數，我們額外加入電漿處理、並利用退火創造晶粒成長，大大的提升氧化物憶阻器的操作次數，以及有效利用增加氧空缺數目降低操作電壓，這也為後續發展電阻式憶阻器奠定了基礎。 本論文的第二部份注重在鐵電式憶阻器的製備與操作流程，我們藉由觀察不同底電極介面的影響，觀察並分析出可以最佳化鐵電薄膜鐵電性的介面條件，並製作超薄鐵電薄膜，並藉由後續包含XPS材料分析、UV-Vis吸收能譜並結合Simmon tunneling model理論公式，觀察鐵電穿隧接面理論與實驗數值是否一致，為後續相關的鐵電穿隧接面憶阻器特性觀察，打下良好的基礎。

This thesis focuses on the synthesis and the characteristic of memristors. The thesis is divided into two main parts. Part 1 puts emphasis on the resistive switching memristors. We demonstrate that crystalline materials are more stable rather than amorphous materials. Although the operation voltage is a little higher in crystalline memristors, the endurance of crystalline memristors is much higher than the amorphous materials. To improve the unfavorable operation voltage, we develop the annealing process and plasma treatment, which effectively lower SET/RESET voltage. In addition, we design a novel structure to mitigate the depletion of oxygen vacancies. Thus, overall endurance increases to 106 cycles and shows excellent performance in multibits operation. Part 2 focuses on the memristors based on the resistive switching in ferroelectric thin films. We first try to prepare stable ferroelectric and CMOS-compatible ultrathin film with a thickness ~3 nm. We design bottom electrode with a rough interface and a specific orientation, which has a significant impact on the ferroelectricity of thin films. Also, we analyze the potential profile of the metal-ferroelectric-metal structure by XPS and UV-Vis techniques. The current-voltage characteristics of the metal-ferroelectric-metal structure match well to the tunneling theory, indicating that ferroelectric tunneling junction is the fundamental mechanism in resistive switching in ferroelectric thin films.