氧化鎳雙極性電阻式記憶體之電性分析

Abstract

本論文，我們利用熱蒸鍍法在P-type 矽基板上，度上一層鎳薄膜。將其放入高溫爐氧化，形成氧化鎳薄膜，並利用鋁，做為此結構的上電極，使用AFM以及XRD分析其表面結構以及晶格結構。 本研究分別針對，氧化溫度與氧氣流量此兩種變因，對此結構的雙極電阻式記憶體性質做分析討論。 實驗結果顯示，在提高氧化溫度下，高阻態與低組態的電阻值會隨者溫度上升而上升；在提高流量之下，高阻態與低組態的電阻值會隨者流量上升而下降。而另外粗糙度的提升，會使元件的電阻轉換性質變得更穩定。 電阻式記憶體是目前尚在發展中的一種新的固態電子元件。其主要的目的在於取代 DRAM與FLASH此兩種記憶體，而目前研究上的挑戰是在於穩定性與持久性這兩個問題上。

In this thesis, a resistive random-access memory was fabricated by using the nickel oxide, grown by thermal evaporation followed by an annealing process at different temperatures, as the dielectric layer sandwiched between the p-type silicon substrate and the aluminum contact. Atomic force microscopy and X-ray diffraction analysis were carried out for the investigation on the surface morphology and the crystalline structure of the grown nickel oxide, respectively. It was revealed that the annealing temperature and the oxygen flow were crucial to the electrical property of the nickel oxide layer. From the experimental results, it was found that the values of high-resistive and low-resistive states will increase with the incremental annealing temperature but decrease with the increasing oxygen flow rate at the optimized annealing temperature. It was also observed that the surface morphology is the key factor for stabilizing the operation of the resistive random-access memory. The results indicated that a nickel oxide film with a rougher surface morphology will greatly improve the lifetime and the reliability of the device. Resistive random-access memory is presently a developing subject for solid state devices and aimed to replace dynamic random-access memory and flash memory. The results in this thesis indicate that the stability and persistence of the resistive random-access memory devices will be the fundamental challenges for its future development.