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標題: | 以陽極氧化技術在矽及碳化矽基板上備製超薄閘極介電層之研究 Investigation of Anodic Oxidation Technique for the Preparation of Ultra-thin Gate Dielectrics on Si and SiC Substrates |
作者: | Kai-Chieh Chuang 莊凱傑 |
指導教授: | 胡振國 |
關鍵字: | 高介電系數閘極氧化層,陽極氧化,碳化矽,金氧半太陽能電池,頻率色散, High-k gate dielectrics,anodization,SiC,MOS solar cell,frequency dispersion, |
出版年 : | 2010 |
學位: | 博士 |
摘要: | This dissertation was focused on the anodic oxidation (anodization) process. First, the anodization is used to improve the electricsl characteristics of high-k Al2O3 on Si substrate. Second, we grow SiO2 on n-type 4H-SiC substrate by anodization.
An anodic field was added in aqueous nitric acid for the improvements of high-k Al2O3 on Si in both current density and reliability. After being annealed in furnace at 650℃ in N2, Al2O3 with equivalent oxide thickness (EOT) of 24-25Å are prepared. It was found that the leakage current, breakdown field, and stress induced leakage current were much improved without sacrificing the interfacial property. This improvement can be ascribed to the compensation oxidation process. On the other hand, MOS solar cells with different Al2O3 thickness are investigated. The best case can achieve an efficiency of 7.2% when the incident light intensity equals 5 mW/cm2. Also, room-temperature anodization is introduced to prepare ultra-thin SiO2 on n-type 4H–SiC. Both the interfacial layer and carbon cluster are not observed. The capacitance equivalent thickness (CET) is about 27-48 Å, and the breakdown field of the grown oxide is higher than 5 MV/cm. The hysteresis of capacitance-voltage curves can be negligible. The positive current conduction is mainly dominated by the Schottky emission, while negative-biased current is limited by carrier generation-recombination. Furthermore, the frequency parameters of anodization were investigated. It is shown that the SiO2 on n-type 4H–SiC substrate by scanning frequency anodization has higher oxide breakdown field and better interfacial properties than that by DC anodization. It is suggested that both the bulk and interface traps in the oxide can be compensated since the scanning frequencies are in close proximity to the response times of interface states. The energy conveyed from the scanning frequency can rebuild the defect bonds in the interfacial region. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/46749 |
全文授權: | 有償授權 |
顯示於系所單位: | 電子工程學研究所 |
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