A unique solid-solid transformation of silver nanoparticles on reactive ion-etching-processed silicon

Processes that combine nanoparticle suspensions with micromechanical or microelectronics platforms can reveal new phenomena unique to nanoscale objects. We report that silver nanoparticles react with silicon wafers that have been patterned by reactive ion etching (RIE) in SF(6)/O(2) plasma. This reaction results in the localized deposition of silver on the patterns. Through the modification of the reaction conditions, the reaction mechanism was explored. Redeposition of the sputtered RIE products is suggested as the key to this transformation. The new silver deposition process was utilized to localize the growth of gold nanoparticles and silicon nanowires on the vertical sidewalls of patterns in silicon, demonstrating a simple route to the fabrication of overhanging nanoscale objects.