Fabrication and metrology of electromagnetically actuated microcantilever arrays for biochemical sensing

Abstract

Since their first applications in atomic force microscopy (AFM) micro-and nanocantilevers have been using as a very versatile tool for nanotechnology for over two decades.Their applications cover fields of micro-and nanomanipulation, micro-and nanocalorimetry, force and mass sensing. Variety of methods and techniques for actuation and detection of cantilevers' motion have been proposed and widely used, each exhibiting its advantages and drawbacks. In this paper we present architecture of the microcantilever whose deflection is actuated electromagnetically by the Lorentz force. Optical beam deflection (OBD) method was used to observe the beam static and resonance displacement. We also present characteristics of the proposed system and describe numerous applications in modern biochemical diagnostics. These include biosensing, mass change detection, nanometer range manipulation and force measurements with the resolution of several piconewtons. In the presented experiments an array of rectangular silicon cantilevers fabricated using double side micromachining was used. A layer of gold was deposited on the top side of the microcantilevers creating a current line for actuation, a reflective pad at the apex, and a substrate for thiol-based self-assembled monolayers (SAMs).