液相沉積氧化矽薄膜沉積機制及其電特性之研究

Abstract

本論文主要探討室溫液相沉積氧化矽薄膜(LPD)的沉積機制以及室溫液相 沉積二氧化矽膜的導電機制,同時並開發其可行之應用.首先,我們研究沉 積溫度,加水量以及矽晶片表面處理條件對於二氧化矽膜的沉積速率及成 長潛伏期的影響.結果發現,當沉積溫度升高或者是加水量增大將會使得二 氧化矽膜的沉積速率增快及縮短成長潛伏期;另外,矽晶片表面處理條件對 於二氧化矽膜成長潛伏期的影響,則主要是決定在矽晶片表面的不同原子 鍵結,當表面鍵結有OH鍵時,二氧化矽膜成長潛伏期則相當短,而當表面鍵 結有Si-F及Si-N鍵時,二氧化矽膜成長潛伏期則相當長.其次我們研究室溫 液相沉積二氧化矽膜的導電機制.結果發現,由於當液相沉積二氧化矽膜的 厚度增大時,由電流密度-電場特性曲線所求出的等效能障高度亦隨之下 降,其導電機制可利用Si-rich氧化膜的導電機制來解釋;同時並研究其可 靠性,結果發現,當氧化層薄化之後,其可靠性也隨之增強.最後,利用以上 結論,我們提出新的當沉積室溫液相沉積二氧化矽膜時所需要的前置氧化 層形成法,我們利用快速熱處理技術來成長前置氧化層取代傳統利用將矽 晶置入HCl+H2O2溶液中所成長的前置氧化層.結果發現,此方法具有相當優 良的電特性及可靠性. In this thesis, we study the deposition mechanism, the electrical characteristics and the electrical conduction mechanism of the thin liquid-Phase-Deposited oxide. And then to develop the application of the thin LPD oxide films. First,we investigate the effect of the deposition temperature, the quantity of H2O addition, and the Si wafer pretreatment on the deposition rates and incubation times of LPD oxidedeposition. The results reveals that the increase of the deposition temperature or the increase of the quantity of H2O addition would resultin higher deposition rateand shorter incubation time. Moreover, the main effect of Si wafer pretreatment on LPD oxide proces is the incubation time which is dominated by the different surface bonding atoms. When the Si surface is constructed of OH bonds, the incubation time is very short. However, when the Si surface is constructed of Si-F or Si-N bonds, the incubation is very long. Then we investigate the electrical conduction mechanism of the thinLPD oxides. The results reveal that as the LPD oxide thickness increase, the effective barrier height decreases which determined from the I-E characteristics. The conduction mechanism of the LPD oxides could be explained by the conduction mechanism of the Si-rich oxides. We also study the electrical reliability ofthe LPD oxides. The results reveal that the thinner oxides shoe better electrical characteristics and reliability.Finally, using the above discussion, we proposed a novel pad oxide formation method by RTP technology to replace the conventional method by immersing the Si wafer in HCl+H2O2 solution. The results reveal that proposed method shows better electrical characteristics and reliability.