ELECTRON-DIFFRACTION STUDY OF AMORPHOUS SILICON-OXIDE FILMS

Amorphous silicon oxide films have been examined by high energy electron diffraction using the sector-microphotometer method of data collection common to gas phase electron diffraction. This data was analyzed with a least-squares procedure that is designed to minimize extraneous detail in the radial distribution function obtained by the Fourier sine transform of the interference function. The results of this analysis for thin film SiO2 show that the overall bonding topology of the thin film agress well with that of bulk (vitreous) SiO2 examined by X-ray diffraction. The experimental short distance parameters for the films whose composition was determined to be ∼SiO1.3, SiO, and SiO0.8 are found to be consistent with those expected for a mixture of tetrahedrally bonded amorphous Si and SiO2 phases in which the scale of the Si-like and SiO2-like regions is of the order of a few basic tetrahedral units. This result is in agreement with previous examinations of SiO powder by X-rays and a previous examination of thin silicon oxide films by electron diffraction. © 1979.