Uniform Si nanostructures grown by oblique angle deposition with substrate swing rotation

Slanted nano-columns and square nano-springs made of amorphous silicon (a-Si) were fabricated on bare Si and patterned substrates by oblique angle deposition with a back-forth substrate swing rotation mode. Scanning electron microscopy was used to characterize the grown nanostructures. The tilt angle of slanted nano-rods is determined by the incident angle of deposition flux and the azimuthal swing rotation angle of a substrate. The controlled substrate rotation affects the uniformity and the shape of the nanostructures. On the patterned substrate, the broadening of the size of individual nano-columns is greatly reduced and the nano-columns are not connected as they grow. A simple model based on decomposing the deposition flux is used to describe the effect of substrate rotation on tilt angle, uniformity, and the top-end shape of nanostructures. The feasibility of fabricating separated and well aligned nanostructures by our swing rotation method provides an effective and controllable way to fabricate nano-devices.