氧化鋁/氧化鈦電阻轉化層之電阻式記憶體特性研究

Abstract

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，快閃記憶體為其大宗，但是快閃記憶體有其微縮極限，其中包含高操作電壓、低存取速度等缺點。 非揮發性電阻式記憶體具備低操作電壓、高操作速度、低功率消耗、結構簡單、微縮能力佳等優點，所以，其發展在下一世代非揮發性記憶體備受期待。 採用氧化鋁/氧化鈦作電阻轉化層製備電阻式記憶體元件，并藉由透過改變不同的上電極(鎳、鈦)來討論元件特性，如電流-電壓曲線、資料保存能力、讀寫次數的量測、電流傳導機制等等。鎳的功函數大約為5.2電子伏特，而鈦的功函數大約為4.3電子伏特，藉由不同功函數的上電極可觀察出對電性的影響。可以看出，這種氧化鋁/氧化鈦作電阻轉化層製備而成的電阻式記憶體元件顯示出較好的特性，在下一世代非揮發記憶體應用中具有良好的潛力。

With the technology development, the nonvolatile memory (NVM) plays an important role in our daily life. The flash memory is considered as the mainstream. However, due to the further scaling limitation, it faces serious challenges, such as high operation voltage, low program/erase (P/E) speed, etc. The resistive random access memory (RRAM) shows a great potential for the next generation NVM application, due to its low operation voltage, high P/E speed, low power and simple structure, etc. In this thesis, we propose a RRAM device using Al2O3/TiO2 as the resistive materials, and also investigate the effect of different top electrode (Nickel, Titanium). The RRAM device characteristics, such as I-V curve, data retention, endurance and conduction mechanism, etc., are investigated. The work function of the Nickel (Ni) is about 5.2 eV, while the work function of the Titanium (Ti) is about 4.3 eV. The top electrode with different work function may have influences for the electrical properties. This Al2O3/TiO2 RRAM device exhibits good memory characteristics, showing a great promise in future scalable memory application.