氮化矽閘極薄氧化層之研究

Abstract

本論文介紹一種新的方法來成長高品質的氮化矽閘超薄氧化層，我們先利用化學氣相沉積一層3.0 nm 的氮化矽薄膜，在乾氧的環境下氧化不同時間，我們發現在這種方式下成長的氮化矽閘極氧化層具有極低的介面井陷密度 (interface-trap density)，其值低於-3×1010 eV-1cm-2。當氧化的時間越長時，氮化矽的介電常數會下降 (K = 4.4~4.7, 比純二氧化矽略高)，且介面井陷密度有逐漸減低的趨勢，其原因為氧分子在高溫下可以穿透極薄的氮化矽層而形成氮氧化矽的緣固。且隨著氧化時間的增加，介電層中氧的含量亦增加。

We have developed a new method of growing high-quality nitride gate dielectric by a simple process using direct thermal oxidation in dry O2 ambient of chemical vapor deposited silicon nitride. A massive improvement in oxynitride integrity is evidenced by the low interface-trap density which is under 3×1010 eV-1cm-2. The interface-trap density decays with the increase of oxidation time of 30A CVD nitride. From the measured capacitance, we can find that the equivalent oxide thickness increases as the K value (which is 4.4 ~ 4.7, a little higher than the one of pure oxide) declines. This is because more oxygen is introduced into the thin nitride film at high temperature during a longer period of oxidation time. CHAPTER II EXPERIMENTAL………………………….3 CHAPTER III RESULTS AND DISCUSSION…………….6 CHAPTER IV CONCLUSIONS…………………………...11 REFERENCES……………………………………………...12 TABLES………………………………..…………………….17 FIGURES……………………………………..………….…..22