DIFFERENT TYPES OF PORE STRUCTURE IN POROUS SILICON

A morphology of pores formed in silicon by its anodic polarization in a hydrofluoric acid has been studied using scanning tunneling microscopy (STM). The results obtained show that the pore structure, as yielded from the STM measurements, may be ordered or fibrouslike depending on the anodic current applied to obtain the porous silicon layers. This dependence is interpreted in terms of the theoretical model assuming the pore growth through a virtual passive layer formation at the pore bottoms and its dissolution.