Nanomachining of (110)-oriented silicon by scanning probe lithography and anisotropic wet etching

Abstract

We have demonstrated that silicon nanostructures with high aspect ratios, having similar to 400 nm structural height and similar to 55 nm lateral dimension, may be fabricated by scanning probe lithography and aqueous KOH orientation-dependent etching on the H-passivated (110) Si wafer. The high spatial resolution of fabricated features is achieved by using the atomic force microscope based nano-oxidation process in ambient. Due to the large (110)/(111) anisotropic ratio of etch rate and the large Si/SiO2 etch selectivity at a relatively low etching temperature and an optimal KOH concentration, high-aspect-ratio gratings with (111)-oriented structural sidewalls as well as hexagonal etch pit structures determined by the terminal etch geometry can be obtained. (C) 1999 American Institute of Physics. [S0003-6951(99)03242-8].