SIMULATION OF THE FORMATION OF POROUS-SILICON STRUCTURES

The formation of porous silicon is investigated by the Monte Carlo met hod in a model that takes account of the nonuniformity of the charge d istribution over the silicon-electrolyte interface, hole diffusion, ge neration, and recombination processes, and size quantization. The stru ctures obtained in a computer simulation for various doping levels of the crystalline substrate, temperatures, HF concentrations, and anode current densities are presented. Analysis of nanoporous structures sho ws that the porosity depends on the depth and reveals the presence of a fractal dimensionality on scales of less than 10 nm. (C) 1997 Americ an Institute of Physics.