Fabrication of high-aspect-ratio nanotips integrated with single-crystal silicon cantilevers

This work presents a novel fabrication technique for an atomic force microscope (AFM) nanotip. The high-aspect-ratio silicon nanotip on a single-crystal silicon cantilever was manufactured using inductive coupling plasma (ICP) anisotropic etching and XeF 2 isotropic silicon etching processes. The cantilever shape was defined and the high-aspect-ratio silicon nanotip structure was fabricated by ICP anisotropic deep silicon etching (∼50–80 µm deep). Nanotip sharpening and single-crystal Si cantilever undercutting were achieved simultaneously via two-step XeF 2 isotropic silicon etching. The final structures were observed by a scanning electron microscope (SEM) and the diameter of the nanotip was about ∼30 nm. This process is simple, easy to use, CMOS post-process-compatible and suitable for the future IC integrated AFM nanotip applications.