HIGH-SENSITIVITY INFRARED CHARACTERIZATION OF ULTRATHIN SIO2 FILM BY GRAZING INTERNAL-REFLECTION METHOD

A new kind of high-sensitivity infrared spectroscopy for characterizing SiO2 ultrathin film of 2-10 nm thickness of metal-SiO2-Si structure has been developed by the grazing internal reflection (GIR) method. At a large incident angle of 80 degrees onto the metal-SiO2-Si interface having SiO2 film of 2 nm thickness, a very large absorption of about 90% has been obtained at around 1240 cm-1 corresponding to the Si-O-Si bond. The measured data including the incident-angle dependence agree well with the calculated values analyzed by Fresnel's formula. Moreover, slight absorptions of Si-H and Si-OH have easily been measured as a strong signal change of about 1-7%.