Deep electrochemical trench etching with organic hydrofluoric electrolytes

porous silicon layers etched through openings in an inert masking layer hav e potential applications for producing microstructures in silicon. In order to overcome the isotropic nature of the porous silicon formation process a round the mask edges, optimized organic electrolytes for etching macropores on p-type silicon were employed. New kind of pores (dubbed "trenches") wer e found, which are sensitive to mechanical stress and may prove useful for microstructuring silicon. Systematic experiments are presented which invest igate the stability, the crystal orientation dependence, and limitations of trench formation. (C) 2001 Elsevier Science B.V. All rights reserved.