Etch-free formation of porous silicon by high-energy ion irradiation...

In this study, porous silicon was fabricated without any chemical etching by self-ion implantation of crystalline Si performed at high temperature and at high fluences. The irradiated silicon samples, which
remained crystalline under high temperature ion irradiation, exhibited an increased porous fraction with
increasing sample temperature at a given fluence, up to the maximum tested temperature of 650 C.
Extremely high ion fluences of at least 2  1018 ions/cm2 were necessary to produce significant void
growth. Comparisons between the porous silicon structures and irradiation-induced porous networks
in Ge, GaSb, and InSb are made, and differences in the formation conditions for these porous networks
are discussed.