An analysis of the radial distribution function of SIOx

A theory is presented for the short-range order (sro) in the SiOx alloy system for 0⩽x⩽2. The parameters of the sro are taken to be fixed by the properties of amorphous Si and SiO2, except that the probability of an Si atom having (i−1) oxygen neighbors is left as a free parameter, Ci(x), for i=1 through 5. The areas of the first three peaks in the radial distribution function (RDF) of SiOx are calculated as a function of x and Ci(x). It is shown that the RDF can be used to differentiate between the two models proposed for the sro in SiOx namely the SiSiO2 mixture model and the random bonding model. In the case of SiO powder, a mixture model at the atomic level is found to be consistent with the RDF. It is suggested that accurate RDF's of SiOx films, which are not currently available, would be useful in determining the sro of the alloy system. The present theory may be extended to analyze the GeOx and SnOx alloy systems.