Fabrication of vertically stacked single-crystalline Si nanowires using self-limiting oxidation

Abstract

A simple method for fabricating vertically stacked single-crystal silicon nanowires onstandard bulk silicon wafers is presented. The process uses inductively coupled plasma(ICP) etching to create silicon fins with uneven yet controllable vertical profiles. The finsare then thermally oxidized in a self-limiting process, and the narrow regions arecompletely consumed to create multiple nanowires vertically stacked on each other. It wasfound that the number of nanowires in the vertical stack depends on the number of ICPcycles. A mechanism for the formation of the nanowires is proposed and confirmed withnumerical simulations.