以硝酸氧化金屬鉿技術製備氧化鉿/二氧化矽堆疊結構之介電層的穩定度分析

Reliability of HfO2/ SiO2 Stacked Structure with Dielectrics Prepared by Nitric Acid Oxidation of Hafnium Metal

張錦昇(Chin-Sheng Chang)

指導教授 ： 胡振國

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.03120

摘要

本篇論文主要探討在低溫硝酸氧化備製氧化鉿/二氧化矽堆疊結構之介電層的穩定度。 在文章中，我們將比較二氧化鉿與二氧化矽這兩種材料。首先，先沉積一層薄鉿金屬在有二氧化矽當緩衝層的P型矽基板上，接著利用硝酸氧化的方法備製出我們需要的二氧化鉿。 為了比較氧化鉿/二氧化矽的特性，二氧化矽被成長出來當對照組。在比較中，我們得知在相同等效氧化層厚度下之氧化鉿/二氧化矽的漏電流比純二氧化矽結構來的低。接著，我們討論氧化鉿/二氧化矽與二氧化矽的一些基本特性，包括:電容與電流對電壓特性和介面特性。 另外，我們將漏電流可以區分為正偏壓與負偏壓兩塊區域，發現電流在負偏壓會跟面積成正比，但在正偏壓的飽和電流則是與周長成正比。此外，二氧化鉿/二氧化矽的穩定性和非理想特性也在本論文中進一步討論。 我們用定電壓測試去分析漏電流的變化和介面特性的好壞，發現二氧化鉿/二氧化矽對電子抓陷的能力較二氧化矽來的強。此外，我們用邊緣電場效應來深入解釋飽和電流的變化現象。實驗顯示出二氧化鉿/二氧化矽有不穩定性被偵測到，而二氧化鉿/二氧化矽的電子抓陷現象的影響是需進一步深入探討的。最後我們提出一些建議供未來改善參考.

關鍵字

高介電值材料 ； 二氧化鉿 ； 硝酸氧化 ； 邊緣電場效應 ； 定電壓測試

並列摘要

In this work, the reliability of the HfO2/SiO2 stacked structure with dielectrics prepared by nitric acid oxidation(NAO) at low temperature is investigated and discussed. Two material dielectrics of HfO2 and SiO2 are compared in this work. First, a thin hafnium metal was deposited on the grown SiO2-IL on p-substrate and then the HfO2 were formed by NAO. In order to compare the characteristic of HfO2/SiO2, the conventional SiO2 dielectric was formed. It is found that the leakage current density of the HfO2/SiO2 is lower than SiO2 at same EOT. The fundamental characterization, such as capacitance characteristics, current-voltage characteristics and the interfacial properties of the HfO2/SiO2 and SiO2 will be discussed. It is found that the leakage current can be described by the negative bias region and positive bias region. The current at negative gate bias is proportional to the device area, but the saturation current at positive gate bias region is proportional to the edge perimeter. In addition, the reliability and non-ideal characteristics of the HfO2/SiO2 will are also discussed. We use CVS test to analyze the variations of leakage current and dielectric property, and it is found that the ability of charge trapping of HfO2/SiO2 is larger than SiO2. Moreover, the fringing field effect was considered to explain the variation of saturation current in more detail. It’s shown that the unstable factors of HfO2/SiO2 are of interest. The impact of the electron trapping phenomena observed in HfO2/SiO2 needs to be explored in detail. Finally, we proposed some suggestions for future work.

並列關鍵字

High-k dielectrics ； HfO2 ； Nitric acid oxidation ； Fringing field effect ； Constant voltage stress

參考文獻

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