Structure Analysis of Thermal Oxide Films of Silicon by Electron Diffraction and Infrared Absorption

Abstract

Electron diffraction data have been used to obtain the radial distribution functions of thermal oxide films of silicon. Influence of multiple scattering of electrons on the intensity was taken into consideration, and a method of correcting for this effect was proposed. The Si–O, O–O, and Si–Si distances were determined to be 1.62, 2.60, and 3.1 Å, respectively. The angle of Si–O–Si bond was estimated to be 147±10°. The shape of an infrared absorption spectrum of the oxide film in a wave number range between 400 and 1,300 cm -1 was similar to that of fused silica. The atomic arrangement in the film is a three-dimensional random network consisting of SiO 4 tetrahedra. Such an atomic arrangement is compared with that of fused silica.