電阻式記憶體(RRAM)有著結構簡單以及單位面積小的優點，故電阻式記憶體在未來非常適合應用在高密度交錯式二微陣列的結構上，以增加記憶體的密度。再加上非揮發性、低耗能、操作速度快以及低成本等優勢，未來將成為記憶體發展的重要趨勢之一。 本實驗分為三個部分，第一部分對鈦金屬(Ti)使用不同快速熱氧化參數所成長的氧化鈦薄膜(TiOx)，再以鉑(Pt)為上電極形成的Pt/TiOx/Ti二極體元件作電性量測分析，探討快速熱退火對所成長之氧化鈦的影響；第二部分是二維雙氧化層電阻式記憶體(MIIM double-layer RRAM)的部分，分別以氧化鉭(TaOx)或氧化鋁(Al2O3)搭配快速熱氧化之氧化鈦，以Ta或Pt為上電極所形成Ta/TaOx/TiOx/Ti與Pt/Al2O3/TiOx/Ti結構，比較並探討兩者的電性；第三部分則是探討將雙氧化層電阻式記憶體實現在三維結構之電性量測分析。由於快速熱氧化的製程方式能夠讓氧化鈦區域性的在垂直結構電阻式記憶體的側壁上成長，改善側壁覆蓋率(step coverage)不佳的問題；再者，快速熱氧化之製程參數如氧氮比、加熱溫度、加熱時間皆可大範圍調變，若能利用此方法成長出合適的氧化鈦薄膜，也能透過電性分析探討其影響；因此，在本研究中皆使用快速熱氧化的方式成長氧化鈦。 在Pt/TiOx/Ti結構之二極體元件測試的實驗中，我們可以看到以快速熱氧化的方式，能夠成功地成長出具有整流特性的氧化鈦薄膜；另外在平面雙氧化層電阻式記憶體的實驗中，我們可以看到不同電阻轉換層的元件，皆不會受到讀取時的偏壓所干擾(read disturbance)，也都具有相當好的資料儲存能力(retention)；在垂直雙氧化層電阻式記憶體的實驗中，我們可以看到以TaOx/TiOx為氧化層的電阻式記憶體，不論是在資料儲存能力或是讀寫測試方面都有不錯的表現，所以證實快速熱氧化的製程方式能夠實現在三維結構的記憶體上。 ;Resistance Random Access Memory (RRAM) has great potentials in two-dimension (2D) high density crossbar array applications owning to its simple structure and small unit area. Moreover, RRAM has many advantages such as nonvolatile property, low power consumption, high operation speed and low cost. With all these benefits, RRAM become one of the best candidates for next generation nonvolatile memory applications. There are three main sections in this thesis. In the first section, the oxidation of titanium is investigated by rapid thermal oxidation (RTO) with different conditions. After depositing Pt as top electrode, the electrical analysis of this titanium oxide (TiOx) is also performed. In the second section, we investigate the characteristics of 2D MIIM double-layer RRAM with tantalum oxide (TaOx) or aluminum oxide (Al2O3) deposited on RTO TiOx/Ti structure with Ta or Pt as top electrodes respectively. In the third section, we will discuss the characteristic of double-layer RRAM realized in 3D structure. We use RTO method to grow titanium oxide since this method allows the film to grow locally on the vertical sidewall which can improve the poor step coverage of PVD film. Furthermore, the adjustable RTO conditions including different O2/N2 ratio, temperature and oxidation time that give the various result of TiOx. Therefore, it is worth to investigate the influence on RTO TiOx that may plays an important role in the double-layer RRAM system. We have successfully fabricated the titanium oxide diode with rectifying characteristic by using RTO method in the first section. In addition, the 2D Ta/TaOx/TiOx/Ti and Pt/Al2O3/TiOx/Ti double-layer RRAM devices have excellent memory retention and the strong immunity to read disturbance ; the 3D double-layer RRAM devices also has the excellent memory retention and the strong immunity to read disturbance , therefore the TiOx formed by RTO process can be used in the three-dimensional MIIM double-layer RRAM.
