Role of spinodal decomposition in the structure of SiOx -: art. no. 245202

On the basis of recent calculations we propose that SiOx fulfills the condition for spinodal decomposition. With this in mind we investigated the nanostructure of room temperature, radiofrequent magnetron plasma sputtered SiOx films over the entire composition range 0less than or equal toxless than or equal to2, applying x-ray photoelectron spectroscopy and infrared analysis. We have found that the majority structure of the materials indeed resembles more or less a phase separated mixture, consisting of (small) a -Si regions and (small) SiO2 regions with Si-SiO3 tetrahedra at the interfaces between the two distinct regions. This structure presumably comes into existence by the operation of the process of spinodal decomposition in the deposition process. This does not seem to hold for sites, where also H (as a minority component in the film) is bonded. We propose that the nanostructure of hydrogenated silicon suboxides is different from that of the nonhydrogenated equivalent material.