The fabrication of porous silicon structures

Porous silicon structures are formed by electrochemical etching of silicon in HF solutions. The selective dissolution of silicon results in the formation of a porous structure with a characteristic morphology dependent on the dopant type and concentration, the applied voltage, and the electrolyte composition. The physical properties of these structures span a wide range with typical pore dimensions of about 30 AA up to 1 mu m and porosities in the range of 0.1 to 0.9 depending on the etching conditions.