ISSG及其氮化工艺对NBTI效应的改善

本文在对ISSG工艺特性简单分析的基础上讨论了ISSG氧化物薄膜的可靠性问题。讨论了ISSG工艺及其相关的氮化工艺对NBTI的改善原理。数据表明ISSG工艺及其相关的氮化工艺对NBTI效应有明显的改善作用。由于原子氧的强氧化作用，ISSG工艺中最终得到的氧化物薄膜体内缺陷少，界面态密度也比较小，氧化物薄膜的质量比较高。ISSG氮化工艺与传统炉管氧化物薄膜的氮化工艺的主要区别在于N所集中的位置不一样。ISSG工艺氮化是把等离子态的N^＋注入到多晶硅栅和SiQ2的界面，不会增加SiQ2和Si衬底的界面态，从而可以显著改善NBTI效应。而传统炉管氧化物薄膜的氮化是用NO或者N2O把N注入到SiQ2和Si衬底的界面，这样SiQ2和Si的界面态就会增加，从而增强NBTI效应。

ISSG Process and Its Improvement on Negative Bias Temperature Instability

We discuss the reliability performance of ISSG （ In-Situ Steam Generation ） gate oxide and analyze the mechanism of NBTI （ Negative Bias Temperature Instability ） improvement by the nitridation process. The ISSG process and the correlated nitridation can significantly reduce the NBTI effect on gate oxide. Due to the strong oxidation of oxygen atoms, the gate oxide produced by the ISSG process has less defects and interface-state densities. The quality of the ISSG gate oxide is better than that of the furnace gate oxide. For the nitridation process in ISSG, nitrogen concentrates at the poly-oxide interface, which can reduce NBTI effect. For the nitridation process in a furnace, nitrogen instead concentrates at the gate oxide-substrate interface, which enhances NBTI effect.