Computer simulations of pore growth in silicon

The dynamics of pore formation in silicon was studied by computer simulation. Porous structures were generated by a Monte Carlo algorithm that controlled the motion of an ensemble of electronic holes on a two-dimensional square lattice. Hole motion was biased to the nearest pore tip in order to simulate local electric-field effects corresponding to the depletion layer setup in n-type silicon. Several morphological characteristics seen in porous silicon were seen in the simulation: highly directional pores, steady-state pore spacing, and a smooth pore front. The pore spacing and the degree of sidebranching depended on the concentration of holes and the magnitude of the bias. The simulation trends are analogous to the pore morphologies seen in n-type silicon.