Abstract

Irradiation of semiconductors with intense femtosecond laser-pulses has recently been demonstrated to provide a versatile means for the fabrication of new materials. Crystalline semiconductors subject to locally intense excitation conditions undergo a transformation: the atomic structure becomes instantaneously disordered and new compounds are “locked in” as the substrate re-crystallizes. Applying this technique to silicon wafers in SF₆ ambient, a highly sulfur doped, optically opaque and hundreds of times more light sensitive surface layer has already been demonstrated (black silicon). Additionally, periodic nano- and microstructures appear on the surface of the wafer that lead to a strong scattering of incident light. This versatile technique can be extended to other technologically important materials to modify local material properties and create doping profiles with micrometer resolution as well as to study laser-induced periodic structures.

© 2011 Optical Society of America