電界効果トランジスタゲートスタック絶縁膜形成機構と絶縁破壊機構統合モデルの研究

利用同步辐射实时x射线光电子能谱（XPS）研究了Si（001）表面的快速温度氧化动力学，同时观察了氧化过程中SiO2的生长速率和界面应变。结果表明，冷却温度使SiO2的生长速率提高了5.0倍。通过扩展统一的Si氧化反应模型，可以很好地解释SiO2的氧化生长动力学，其中氧化生长速率dRSiO2/dt与界面应变的增加成正比。这表明，在低温下，氧化物新生长的地方周围容易发生进一步的氧化，导致SiO2/Si界面形貌粗化。采用XPS、紫外光电子能谱和扫描隧道显微镜对Si（001）和Si（111）表面生长的极薄氧化层的热分解动力学进行了实验研究，从分解诱发应变的角度阐明了孔隙成核和生长反应机制。观察到，在孔洞成核过程中，应变Si原子的数量与氧化物分解的数量成正比地增加。这是通过使用提出的分解模型来解释的，其中在累积空洞区域的外围存在应变的下冲剖面，并且下冲应变的大小与空洞的数量成比例地增加。在以上研究的基础上，验证并进一步扩展了由氧化物生长和氧化物分解组成的统一硅氧化反应模型。

The rapid temperature oxidation kinetics on Si(001) surfaces was investigated by real-time X-ray photoelectron spectroscopy (XPS) using synchrotron radiation to observe the SiO2 growth rate and interfacial strain simultaneously during oxidation. It was observed that the SiO2 growth rate was enhanced 5.0 times by cooling temperature. The SiO2 oxide growth kinetics is interpreted well by extending the unified Si oxidation reaction model, where oxide growth rate dRSiO2/dt is in proportion to the increase of the interfacial strain. This implies that further oxidation is prone to occur around the place where oxides are newly grown at low temperature, leading to a roughening of the SiO2/Si interface morphology. The thermal decomposition kinetics of very thin oxide layers grown on Si(001) and Si(111) surfaces were investigated experimentally by XPS, ultraviolet photoelectron spectroscopy and scanning tunneling microscopy to clarify the void nucleation and growth reaction mechanisms from a viewpoint of the decomposition-induced strain. It was observed that the amount of strained Si atoms increased in proportion to the amount of oxide decomposed during the void nucleation. This was interpreted by using a proposed decomposition model, where there is an undershoot profile of the strain at the periphery of the accumulated void area and the magnitude of the undershoot strain increased in proportion to the amount of vacancies.Based on the above studies, the unified Si oxidation reaction model consist of both the oxide growth and oxide decomposition was verified and further extended.