Crystallographic aspects of pore formation in gallium arsenide and silicon

Abstract

Abstract The structure of porous layers formed in n-type GaAs is characterized and compared with the more familiar structure of porous n-type Si. Pores in n-type GaAs run in 〈111〉a directions and have triangular or hexagonal cross-sections; their size and degree of branching depend on the doping level and current density. The characteristic differences between porous GaAs and porous Si are explained by a model in which we consider the bonding configuration of atoms on steps. Kinks and terraces on the interior of the pore and the spatial ditribution rate-limiting electrochemical reactions.