MECHANISM FOR THE FORMATION OF POROUS SILICON

A study has been made of how defects and stress in the substrate affec t the uniformity of the formation of porous silicon films during anodi c etching of a silicon substrate in hydrofluoric acid. In regions of a n elevated concentration of defects and stress, there is a transition from a region in which porous silicon is formed to an electropolishing regime. An energy mechanism is ro sed for a local nucleation of voids at a silicon surface.