ABSTRACT
This chapter evaluates ion beam treatment onto porous silicon (PSi) wafers in view of an additional decrease of their thermal conductivity (TC) due to partial or total amorphization of the material. It investigates the "response" of PSi targets to ion irradiation dominated by electronic slowing-down processes. A scanning electron microscopy (SEM) image of PSi fabricated in this way is presented. The PSi formed is of dendritic silicon quasi-columns, with a diameter on the order of 10 nm perpendicular to the wafer surface, and separated by pores. These quasi-columns remain monocrystalline and retain the crystalline orientation of the substrate. This morphology is typical of the so called mesoporous structure of PSI. The amorphization is assumed to result from the following mechanism: the PSi small ramification melt due to electronic interaction, as can be explained by the thermal spike model, and lose their crystallinity during re-solidification.
