The researchers etched a pattern of notches into a silicon wafer and deposited a layer of silicon nitride on top. The notches set up stresses within the nitride layer that cause it to crack in line with the underlying wafer's crystal structure, which acts as a guide.

The nano-cracks could serve as channels for lab-on-a-chip type applications such as single-molecule sensing. Electron beams are currently used to etch atomic-scale patterns, but this is time-consuming and expensive. By contrast, cracks form instantaneously, according to the scientists.