A Top-Down Fabrication Process for Vertical Hollow Silicon Nanopillars

Hollow silicon nanopillars (HSiNPs) have been fabricated from a single crystal silicon wafer by a series of standard top–down microfabrication processes, specifically by an ambient temperature Bosch process using the nanosphere beads as the mask. The dimensions of the hollow silicon nanopillars can be tuned with an outer diameter in the range of hundreds of nanometers and inner diameter from 70 to 700 nm. The density of the HSiNPs can be as high as
$1.3 \,\, \times \,\, 10^{8}$
/cm
²
and their height-to-width aspect ratio can be as high as 20. The ratio of the wall thickness to the outer diameter of the HSiNPs can be tuned from 1/3 to 1/16. This process could be adapted or modified to fabricate hollow nanopillars from different semiconductors, oxides, and metals, thereby offering a generic method for fabricating hollow nanopillars. [2016-0021]