2-SCALE MODEL FOR AGGREGATION AND ETCHING

We propose a dual scale drift-diffusion model for interfacial growth a nd etching processes. The two scales are (i) a depletion layer width D elta W surrounding the aggregate, and (ii) a drift length l. The inter play between these two antithetical scales yields a variety of distinc t morphologies reported in electrochemical deposition of metals, in vi scous fingering in fluids, and in porous silicon formation. Further, o ur algorithm interpolates between existing growth models (diffusion Li mited aggregation, ballistic deposition, and Eden) for limiting values of Delta W and l.