Silicon monoxide role in silicon nanocluster formation during Si-rich oxide layer annealing – Monte Carlo simulation

A kinetic Monte Carlo model of silicon nanocluster (Si-nc) formation during high temperature annealing of Si suboxide layers was suggested. The model takes into account, along with silicon and oxygen atom diffusion, the processes of silicon monoxide creation and dissociation. It was demonstrated that the presence of SiO in the system results in an increase of Si-nc critical nuclear size and can accelerate nanocluster growth. It was found that Si-ncs were formed only in the SiOx layer with x < 1.8. Three stages of Si-nc aggregation were revealed: silicon cluster nucleation, coalescence of neighbor Si-ncs, and slow enlargement of separately located clusters. Annealing of the SiO2 film containing nonstoichiometric SiOx layers resulted in Si-nc or cavity formation depending on temperature. The type of the process was determined by ratio between SiO dissociation and evaporation rates.