5 MHz, 2 N/m piezoresistive cantilevers with INCISIVE tips

Abstract

Piezoresistive atomic-force-microscope (AFM) cantilevers with sensitivities of (ΔR/R)/angstroms = 1.1×10-5, displacement resolutions of 2×10-3 angstroms/√Hz, mechanical response times of less than 90 ns, and stiffnesses of 2 N/m have been fabricated from a silicon-on-insulator (SOI) wafer using a novel frontside-only release process. To reduce mass, the cantilevers utilize novel INCISIVE (IN-plane, CrystallographIcally-defined-SIlicon, VariablE aspect-ratio) tips with radius of curvature of 40 angstroms. The cantilevers have been used in an experimental AFM data storage system to read back data with an areal density of 10 Gb/cm2. Some cantilever designs have sufficient displacement resolution to detect their own thermal vibration in air. The INCISIVE tips also have applications to other types of sensors.