Thermodynamics of silicon carbide nucleation during the carbonization of nanoporous silicon

A nucleation theory is proposed to describe the dynamics of formation of 3C-SiC nanocrystals during the carbonization of nanoporous silicon. A Monte Carlo simulation shows that spherical 3C-SiC nanocrystals form in quantum silicon wires in the first seconds, which coincides with the initial time of fusion of the pore walls. The energy barrier to silicon carbide nucleation is thermodynamically calculated, and the barrier is shown to be overcome due to a change in the pore wall area and, correspondingly, surface energy release. The proposed theory can be used to describe the necessary conditions of formation of 3C-SiC nanocrystals and explains why they do not form in single-crystal silicon.