Fabrication of single-crystal Si cantilever array

Abstract

Abstract For the purpose of improvement in resolution of force gradient and mass detection in atomic force microscopy (AFM), we are developing cantilevers measuring a few microns. We succeeded in fabrication of a single-crystal Si cantilever with several microns size and measurement of its mechanical characteristics. A silicon-on-insulator (SOI) wafer was used for the fabrication. Fabrication was based on three anisotropic etching processes by KOH and two local oxidation processes of Si. Without depending on precision of lithography technique, triangular cantilevers measuring a few microns with tetrahedral tips on their ends were fabricated with high uniformity. The thickness of the cantilever could be chosen from 20 to 200 nm. Typical spring constants, resonance frequencies and Q factors of the single-crystal Si cantilevers were 0.01–10 N/m, 1–100 MHz and around 104 in vacuum. The density of the cantilever is up to 1 million cantilevers per cm2. One cantilever can be used for high sensitivity AFM or used in parallel to image a large area with high time efficiency.