三元材料(鋯、釔、氧)閘極介電層效應之研究

Abstract

本論文利用共濺鍍的方式將鋯摻雜於氧化釔層，並且進行550 ℃、700 ℃和850 ℃的快速熱退火，接著將鋁電極沉積上去就會形成Al/ZrN/Y2O3/Y2O3+Zr/p-Si和Al/ZrN/Y2O3+Zr/Y2O3/p-Si兩種結構，所沉積的氧化層厚度為7 nm。 研究結果指出，當摻雜Zr在上層的時候，透過XRD圖看出結晶的程度要來的比Zr在下層要來的嚴重，代表Zr有抑制氧原子擴散的效果，從AFM也顯出出Zr在上層的面粗糙度也較差。在電性部分，Zr在上層者造成整體的漏電流會較大。最後在蕭基發射漏電流機制方面，透過相同直流濺鍍瓦數以及相同退火溫度的試片作比較分析，發現當Zr摻雜在下層時有較高的能障。顯示出造成較低漏電流的結果有可能之主要因素是由於有較高的能障。

In this study, zirconium (Zr) was doped into the Y2O3 layer through co-sputtering before rapid thermal annealing (RTA) at 550 ℃, 700 ℃, and 850 ℃and Al electrode formation. Two structures were formed: Al/ZrN/Y2O3/Y2O3+Zr/p-Si and Al/ZrN/Y2O3+Zr/Y2O3/p-Si. When Zr was doped on the upper layer, the crystallization was more significant than when Zr was doped on the bottom layer, as shown in the X-ray diffraction (XRD) diagram. This result showed that Zr can suppress oxygen diffusion. Additionally, the atomic force microscopy (AFM) data also showed that the surface roughness was worse when Zr was doped on the upper layer. With regard to electrical properties, the overall leakage increased when Zr was doped on the upper layer (i.e. Al/ZrN/Y2O3+Zr/Y2O3/p-Si). Finally, regarding the Schottky emission mechanism, we compared and analyzed the samples of the same DC power and same annealing temperature. We found that the barrier height was higher when Zr was doped on the bottom layer (i.e. Al/ZrN/Y2O3/Y2O3+Zr/p-Si). The higher barrier height may be the dominant factor to result in a lower leakage current.