二氧化鉿電阻式記憶體之微縮特性研究

The research of scaling down in HfO2 RRAM

曾柏憲(Bo-Shian Tzeng)

指導教授 ： 周正堂 ； 李耀仁

國立中央大學/工學院/化學工程與材料工程學系/碩士(2012年)

摘要

電阻式記憶體(RRAM)可以說是目前最簡單結構的記憶體，而由於結構簡單所以非常適合用來微縮。再配合原有的非揮發性、快速存取能力、低耗能、低成本、保存資料能力佳的優勢，使得在未來新時代記憶體中備受矚目。如果再使用3D結構來增加密度，那電阻式記憶體在發展高密度元件有著非常強大的潛力。
而為了探討電阻式記憶體的微縮性，本實驗利用Ni/HfO2/Si的Contact hole以及Crossbar的結構，並使用不同的電極大小來微縮，而發現在這些結構中在小尺寸都會有Forming fail以及Reset fail的現象，但也了解使用比較薄的介電層由於降低Vforming可以有效的提升元件的可靠度，也了解到機台限流其實並不可靠，由於機台本身的限制，會有overshoot current，為了避免此現象一定要用1D1R或1T1R的結構才可避免。另外在記憶體中發現可以藉由限流來分離氧空缺燈絲(OF)以及金屬燈絲(MF)，而在使用氧空缺的燈絲時，會具有低功率操作的特性，再配合不同的電極，可以讓原本會出現DBIE現象的元件可以順利微縮。

關鍵字

二氧化鉿 ； 微縮 ； 電阻式記憶體

並列摘要

Resistance Random Access Memory (RRAM) is the most simplified structure of memory, and it can be easily scaled down. RRAM has many advantages such as non-volatile property, high speed operation, low power consumption, low cost, and high data density. RRAM is the best candidate for high density device in the next generation.
In this study, we used Ni/HfO2/Si as contact hole and crossbar structure, and used different electrode sizes to scale down. But it showed “forming fail” and “reset fail” in tiny scale. Nevertheless, using thicker TMO can reduce Vforming and enhance reliability in the device. At the same time, we also realized that the instrumental compliance was not fully dependable, so it had overshoot current which could damage the device. We must use 1D1R or 1T1R structure to avoid the overshoot current. Besides, the device can use different compliance to separate the oxygen filament (OF) and metal filament (MF). When using the OF mode with different top electrode materials, it had lower power consumption. So we can reduce “forming fail” and “reset fail” probability.

並列關鍵字

oxygen vacancy ； scaling down ； filament ； RRAM ； HfO2

參考文獻

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