Computer modelling of porous silicon formation

Porous silicon formation has been simulated by the finite diffusion length (FDL) model. This considers a dynamic isoconcentration profile from which the aggregating particles begin their random walks. In this paper we report on the isoconcentration profile non-uniformities which increase as the finite diffusion length is increased. The implementation of the FDL model with zero diffusion length generates non-fractal structures with a fractal dimension close to 1. It is found that Eden clusters cannot be generated at zero diffusion length, due to the problem of sinking isoconcentration profile. We conclude that these are limitations that should be considered in the FDL model for improving the understanding of physical phenomena such as formation and morphology of porous silicon.