Electroless etching of Si with IO3 – and related species
1 Department of Chemistry, West Chester University, West Chester, PA, 19383, USA
2 Present address: Chemistry Department, Exelon Corporation, Plant Services Building, 1848 Lay Road, Delta, PA, 17314, USA
Nanoscale Research Letters 2012, 7:323 doi:10.1186/1556-276X-7-323Published: 20 June 2012
We have previously derived seven requirements for the formulation of effective stain etchants and have demonstrated that Fe3+, Ce4+, and VO2+ + HF solutions are highly effective at producing nanocrystalline porous silicon. Here, we show that Cl2, Br2, I2, ClO3–, BrO3–, IO3–, I–, and I3– induce etching of silicon when added to HF. However, using the strict definition that a pore is deeper than it is wide, we observe little evidence for porous layers of significant thickness but facile formation of pits. Iodate solutions are extremely reactive, and by the combined effects of IO3–, I3–, I2, and I–, these etchants roughen and restructure the substrate to form a variety of structures including (circular, rectangular, or triangular) pits, pyramids, or combinations of pits and pyramids without leaving a porous silicon layer of significant thickness.