QUANTITATIVE ANALYSIS OF NITROGEN PROFILES IN ULTRATHIN OXYNITRIDE GATE DIELECTRIC FILMS

1.利用SIMS测量了氮氧化硅超薄薄膜(~2.6 nm)中的氮气深度分布。将结果与高分辨率RBS(HRBS)测量的轮廓进行比较，以查看SIMS在最上面的1-2 nm区域是否能够准确。使用恒定的RSF因子进行SIMS分析，SIMS与HRBS之间的一致性并不令人满意。SIMS低估了较大浓度下的氮浓度，可能是由于基质效应。由观测结果推导出了经验成分相关的RSF因子。用经验RSF因子对SIMS结果进行修正后，除最表层(d&lt；0.3 nm)外，氮的深度分布与HRBS结果吻合得很好。通过对Si(001)进行臭氧和热氧化，然后快速热氮化，制备了超薄的氮氧化硅薄膜。用高分辨率卢瑟福背散射光谱测量了这些薄膜中的氮深度分布。观察到的氮气分布基本相同，在SiO_2/Si界面处有一个峰值，尽管臭氧氧化物中的界面应变比热氧化物中的小得多。这表明，由于氮掺杂引起的界面应变松弛不是导致界面氮积累的原因。

1. Nitrogen depth profiles in ultrathin silicon oxynitride films (〜 2.6 nm) are measured by SIMS. The results are compared with the profiles measured by high-resolution RBS (HRBS) to see if SIMS can be accurate in the topmost 1 - 2 nm region. Using a, constant RSF factor for SIMS analysis, agreement between SIMS and HRBS is not satisfactory. SIMS underestimates the nitrogen concentration at larger concentrations probably due to matrix effects. The empirical composition-dependent RSF factor is derived from the observed results. Correcting the SIMS result with the empirical RSF factor, the nitrogen depth profiles agree with the HRBS results reasonably well except for the very surface region (d < 0.3nm).2. Ultrathin silicon oxynitride films are prepared by ozone and thermal oxidation of Si(001) followed by rapid thermal nitridation. The nitrogen depth profiles in these films are mesured by high-resolution Rutherford backscattering spectroscopy. Observed nitrogen profiles are essentially the same having a peak at the SiO_2/Si interface, although the interfaces strain in the ozone oxide is much smaller than that of the thermal oxide. This indicates that the interface strain relaxation due to the nitrogen incorporation is not responsible for the nitrogen accumulation at the interface.