Atomic scale control of high-k dielectric ultrathin film grown by atomic layer-by-layer MOCVD with using in situ spectroscopic ellipsometry monitoring

1.采用原子层-层金属有机化学气相沉积（MOCVD）技术制备了有望成为未来小型MOSFET器件高k栅介质的HfO_2薄膜。利用直接安装在沉积室中的椭偏仪，对HfO_2薄膜生长过程进行了实时椭偏测量，为HfO_2薄膜生长过程的优化提供了一种有效的方法。2.利用HfO_2、SiO_2和Hf硅酸盐的光学介电常数计算结果，分析了HfO_2沉积过程中椭偏光谱的时间演化规律。模拟了薄膜生长初期界面层的形成和随后氧化层的形成，这些结果与横截面TEM图像和EDX分析的结果定性一致。3.采用MOCVD方法制备了Pr硅酸盐薄膜。从角分辨X射线光电子能谱分析，在硅/Pr硅酸盐界面的价带偏移和Pr硅酸盐的带隙估计。结合J-V和C-V测量结果，我们可以得出结论：硅酸镨是下一代MOSFET高k栅介质的合适材料之一，其EOT小于1.0nm。

1.HfO_2 ultrathin films which are expected to be alternative high-k gate dielectrics for future miniaturized MOSFET devices are fabricated by the atomic layer-by-layer mete-organic chemical vapor deposition (MOCVD). By using an ellipsometer directly installed to the deposition chamber, we performed in situ real-time ellipsometry monitoring of HfO_2 thin film growth, and showed that this method was useful for process optimization of ultrathin film growth.2.Time evolution of in situ spectroscopic ellipsometry spectra during HfO_2 deposition was analyzed by using the calculated results of optical dielectric constants of HfO_2, SiO_2, and Hf silicate. Formation of interfacial layer at an initial stage of film growth and the following oxide formation are modeled, and these results are qualitatively consistent with the results of cross sectional TEM images and EDX analysis.3.Pr silicate ultrathin films are fabricated by MOCVD. From the angle-resolved X-ray photoelectron spectra analysis, valence band offsets at the Si/Pr silicate interface and band gaps of Pr silicate are estimated. Together with the results of J-V and C-V measurements, we can conclude that Pr silicate is one of suitable materials for high-k gate dielectrics of the MOSFET at the future generation with the EOT of less than 1.0nm.