A study of buried channel formation in oxidized porous silicon

Abstract

We have studied the formation of buried, hollow channels in oxidized porous silicon produced by a process based on focused high-energy ion irradiation of low resistivity, p-type silicon. This is followed by electrochemical anodization and various oxidation stages, all of which may influence the channel size, shape and roughness. We have identified several mechanisms by which the irradiation fluence can alter the channel size and shape, and studied the dependence on anodization current density and oxidation temperature. A low anodization current density combined with high temperature oxidation results in hollow channels in oxidized porous silicon being shrunk to dimensions of about 50 nm. Highly smooth, symmetric channels are produced using viscous flow of the oxidized porous silicon during high temperature oxidation.