Two- and three-dimensional microstructures produced by electrochemical etching of silicon

This work reports on the fabrication of two- (2D) and three-dimensional (3D) microstructures starting from the macropore formation by electrochemical etching of n-type silicon. We describe some critical effects of the etching process that act as sources of degeneration to the otherwise perfect pore pattern. We also give the solutions to improve the pore uniformity and produce high-aspect-ratio macropores with good structural characteristics. The obtained macroporous structures can be further processed to produce high-aspect-ratio pillars, instead of pores. Besides, by modulating the etching current we have also induced periodicity in the third dimension. Possible applications of the presented structures are discussed.