Optical and bonding model for non-crystalline SiOx and SiOxNy materials

Optical data for non-crystalline SiOx materials are presented and analyzed for the energy region 1 to 26 eV. The results indicate that amorphous substances of all intermediate compositions between Si and SiO2 can be formed and that these materials are not simple mixtures of particles of Si and SiO2 but rather the two atom species are blended on an atomic scale. The basic units of this structure are Si tetrahedra (perhaps highly distorted) of the type Si(SiyO4−y) in which the distribution of atoms for all y = 0 to 4 is statistical for any given atom ratio. Further it is found that the optical properties of these layers are determined by the presence and grouping of SiSi and SiO bonds and that clusters of like bonds of the dimension of a Si(Si4) or Si(O4) tetrahedra have optical properties comparable to those exhibited by amorphous silicon or quartz respectively “in bulk”.