Fabrication of single-crystal silicon nanowires based on surface wet adhesion

Abstract

In this paper, we present a top–down fabrication method of single-crystal silicon nanowires. The method employs the popular photolithography technique and etching-rate dependent on the crystal orientation of single-crystal silicon in KOH solution. Using surface wet adhesion and reduced silicon dioxide etching, nanoscale SiO2 mask line patterns with width from 45nm to 200nm and length up to 120µm are successfully patterned. The interspace between nanoscale SiO2 mask lines is 750nm, which is narrower than the 1.2µm feature resolution of obtainable photolithography process. A mechanism for explaining the creation of nanoscale SiO2 mask lines based on surface wet adhesion due to the capillary force is suggested and discussed. The single-crystal silicon nanowires have been successfully fabricated by transferring the nanoscale SiO2 mask line patterns into the top silicon layer of SOI wafer by KOH anisotropic wet-chemical etching.