Spinodal decomposition versus nucleation and growth mechanism of phase separation in nonstoichiometric silicon oxide films during high temperature annealing

In this work, kinetic mechanisms of phase separation in nonstoichiometric Si oxide (SiOx) films during high temperature annealing are studied theoretically. Analysis of the composition dependence of the Gibbs free energy of SiOx phase is carried out to derive its binodal and spinodal characteristics. The ranges of the values of x corresponding to stability, metastability, and instability of nonstoichiometric Si oxide with respect to phase separation are determined as the functions of annealing temperature and SiOx elastic properties. The composition-temperature regions of the spinodal decomposition and the nucleation and growth mechanisms of phase separation are presented. Obtained results open a way to a development of the kinetic theory of phase separation in SiOx films and formation of Si quantum dots/SiO2 matrix composite structures.