氧化鋁/二氧化鈦 電阻式記憶體元件的低功率開關特性探討

Abstract

隨著科技的日益進步，非揮發性記憶體在我們生活中扮演著重要的角色，像是手機、數位相機和筆電，非揮發記憶體在這幾年半導體工業有更多的需求。在現今快閃記憶體為其主流，但是快閃記憶體有其微縮極限，面臨極大的挑戰。非揮發記憶體科技已經擴大發展來達到低功率損耗、高速開關轉換和好的耐受度。電阻式記憶體在下個世代的非揮發記憶體應用擁有好的潛力，因為電阻式記憶體的低開關電壓、高速開關轉換、低功率、高密度的整合和簡單的結構…等等，被認為是在下個世代的非揮發記憶體應用上擁有好的潛力。 此篇論文的研究，我們報告指出不同上電極(鎳，氮化鉭)的影響和以鎳/氧化鋁/二氧化鈦/氮化鉭的電阻式記憶體結構的低功率電阻式開關為0.752毫瓦 (188微安培，4伏特; 2.6微安培 在-5伏特)。電阻式記憶體元件的特性，例如 開/關 電阻比(大於100)， 資料的保存時間(104秒 溫度60度)，合適的脈波的耐受力(50個週期)，電流的分布，和導電物理機制等，在此研究報告上，上電極隨著不同的功函數可能會影響電性。此電阻式記憶體元件指出載子的傳導主要是由載子透過材料的缺陷，像是在電阻式記憶體絕緣層裡的氧空缺，為載子跳躍導電機制。像這樣的低功率開關在未來的微縮記憶體應用上是非常有前景的，是此電阻式記憶體元件的優點。

As the technology development, the nonvolatile memory (NVM) plays an important role in our daily life, such as mobile phones, digital cameras and laptop, have significantly increase the demand for nonvolatile memory (NVM) with the years in semiconductor industry. The flash memory nowadays is considered as the mainstream. However, due to the further scaling limitation, it faces serious challenges. The resistive random access memory (RRAM) shows a great potential for the next generation NVM application, due to its low operation voltage, high-speed switch, low power, high density integration and simple structure, etc. In this study, we report the effect of different top electrode (Nickel, Tantalum Nitride) and a low 0.752mW (188μA at 4V; 2.6μA at -5V) power resistive switching RRAM device with Ni/Al2O3 (6nm)/TiO2/TaN RRAM structure. The RRAM device characteristics, such as on/off resistance ratio (>100), data retention (104s at 60℃), satisfactory pulse switching endurance (50 cycles), current distribution, and conduction mechanism, etc., are investigated. The top electrode with different work function may have influences for the electrical properties. This RRAM device indicates that the carrier transport is dominated by the hopping conduction via material defects such as oxygen-vacancies in this RRAM. Such as low-power switching is a great promise for future scalable memory application, a merit of this RRAM.