Infrared properties of ultrathin oxides on Si(100)

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• 作者：Giustino ; Feliciano ; Pasquarello ; Alfredo
• 关键词：Si/SiO₂ interface ; infrared spectra ; dielectric permittivity
• 刊名：Microelectronic Engineering
• 出版年：2005
• 出版时间：June 17, 2005
• 年：2005
• 卷：80
• 期：Complete
• 页码：420-423
• 全文大小：345 K

文摘

We study the infrared absorption spectra of ultrathin SiO₂ films on Si(100) using a first-principles approach, and adopting a model Si(100)-SiO₂ interface with a realistic transition structure. We calculate both the transverse-optical and the longitudinal-optical infrared absorption spectra across the interface, and show that the red shift of the high-frequency peaks observed experimentally with decreasing oxide thickness originates from the softer vibrational frequencies of the substoichiometric interfacial layer. From the calculated infrared properties, we are able to assess the effect of the frequency softening on the corresponding static permittivity.