ANODICALLY GROWN POROUS SILICON STRUCTURE - FORMATION MECHANISMS

It is experimentally shown, in porous silicon formation, that there is an increase in dissolution rate at fluorine-covered sites of the sili con surface due to the presence of excess electrons coming from the ox idation of molecular hydrogen at hydrogen-covered sites. The increase in dissolution rate in the presence of excess charge at the fluorine-c overed sites is investigated theoretically by a semi-empirical Hartree -Fock calculation which shows that this spatially variable dissolution generates the porous silicon structure.