Incipient chemical reaction on the scratched silicon {111} surface with ethoxy and hydroxy groups

Incipient reactions on the scratched Si {111} surface with solutions containing KOH, ethanol, and tetraethyl orthosilicate (TEOS) were examined. In situ scratching in the TEOS solution was also carried out for comparison. A remarkable increase in the dangling bond concentration was detected on the scratched silicon surface by ESR. Similar hemispherical gel deposits were observed parallel to the uniformly coated gel film on the scratched sample after etching by an ethanol/KOH solution as well as by in situ etching in an ethanol/TEOS solution. The hemispherical deposition, being localized at the tip of branched cracks where KOH solutions also preferentially attack, indicates that the incipient chemical reaction on the scratched silicon {111} with ethoxy groups preferentially initiates at the crack tip, as a result of siloxane polycondensation after concurrence of competitive adsorption of ethoxy over hydroxy groups at the concentrated dangling bonds.