電阻式記憶體之多功能應用

Functional applications based on resistive switching memory

康振方(Chen-fang Kang)

指導教授 ： 曾雪峰

國立臺灣大學/電機資訊學院/光電工程學研究所/博士(2015年)

https://doi.org/10.6342/NTU.2015.01323

摘要

電阻隨機存取存儲器（Resistive random access memory）具備優越的可擴展性，低功耗和高速。但從材料科學角度，探討最佳電阻隨機存取存儲器的材料仍然是實際應用中不可或缺的。在這項工作中，一種新的材料铋錳氧（BiMnO3）進行了記憶體的電性研究，包括開關性能，穩定性和耐力測試。此外，該記憶體轉態原理歸因於材料內部金屬導電納米燈絲的形成與破壞已經被證實。更重要的是，利用交叉桿結構單一奈米燈絲形成/破壞的功率消耗低至3.8 / 20 fJ。同時利用铋錳氧首次對ZT的主動增益提出一種通用的方法（從0.35到1.08）。通過各種材料的電阻轉態在沒有任何額外的製造工藝情況下發現可提高熱電轉換品質。利用導電納米燈絲的形成和破壞可切換熱電轉換品質。這項研究有助於了解電阻式記憶體的操作機制以至於不同領域的相關應用包括低功率記憶體元件，高密度元件和熱電元件應用。

關鍵字

奈米燈絲 ； 操作能量 ； 超低功率 ； 記憶體 ； 熱電轉換效率增益 ； 複雜氧化物

並列摘要

Resistive random access memory (RRAM) is one of the most promising candidates as a next generation nonvolatile memory (NVM), owing to its superior scalability, low power consumption and high speed. From the materials science point of view, to explore optimal RRAM materials is still essential for practical application. In this work, a new material (Bi, Mn)Ox (BMO) is investigated and several key performance characteristics of Pt/BMO/Pt structured device, including switching performance, retention and endurance, are examined in details. Furthermore, it has been confirmed by high-resolution transmission electron microscopy that the underlying switching mechanism is attributed to formation and disruption of metallic conducting nanofilaments (CNFs). More importantly, the power dissipation for each CNF is as low as 3.8/20 fJ for set/reset process, and a realization of cross-bar structure memory cell is demonstrated to prove the downscaling ability of proposed RRAM. The pursuit of improving the figure of merit of thermoelectric efficiency (ZT) in thermoelectric materials has been an ongoing endeavor for the past decades. We for the first time show a straightforward, and generic approach for a drastic enhancement of ZT (from 0.35 to 1.08 in (Bi, Mn)Ox (BMO) thin films, for example) via the resistive switching process applied for a variety of materials without any additional materials and manufacturing processes. Using formation and disruption of conductive nanofilaments with ~10 nm in diameter, a switchable and stable ZT (switched from 0.18 to 1.08 in BMO with origin ZT of 0.35, for example)) can be electrically controlled, which is confirmed by the transmission electron microscopy. This study paves a new way for enhancing/controlling ZT factor in the future thermoelectric development at mass production scale. These distinctive properties have important implications for understanding switching mechanisms and implementing ultralow power-dissipation and thermoelectric device based on RRAM.

並列關鍵字

Nanofilament ； Operating energy ； Ultralow power ； Memory ； Thermoelectric ZT enhancement ； Complex metal oxide

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