title: Multi-MHz micro-electro-mechanical sensors for atomic force microscopy.
abstract: Silicon ring-shaped micro-electro-mechanical resonators have been fabricated and used as probes for dynamic atomic force microscopy (AFM) experiments. They offer resotnance frequency above 10MHz, which is notably greater than that of usual cantilevers and quartz-based AFM probes. On-chip electrical actuation and readout of the tip oscillation are obtained by means of built-in capacitive transducers. Displacement and force resolutions have been determined from noise analysis at 1.5fm/√Hz and 0.4 pN/√Hz, respectively. Despite the high effective stiffness of the probes, the tip-surface interaction force is kept below 1 nN by using vibration amplitude significantly below 100pm and setpoint close to the free vibration conditions. Imaging capabilities in amplitude- and frequency-modulation AFM modes have been demonstrated on block copolymer surfaces. Z-spectroscopy experiments revealed that the tip is vibrating in permanent contact with the viscoelastic material, with a pinned contact line. Results are compared to those obtained with commercial AFM cantilevers driven at large amplitudes (>10nm).
authors.affiliation: LAAS-CNRS, Université de Toulouse, CNRS, 7 avenue du colonel Roche, F-31400 Toulouse, France. Electronic address: bernard.legrand@laas.fr.
authors.forename: Bernard
authors.initials: B
authors.lastname: Legrand
authors.affiliation: CRPP, 115 avenue Schweitzer, F-33600 Pessac, France.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Salvetat
authors.affiliation: IEMN, avenue Henri Poincaré, F-59652 Villeneuve d'Ascq, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Walter
authors.affiliation: IEMN, avenue Henri Poincaré, F-59652 Villeneuve d'Ascq, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Faucher
authors.affiliation: IEMN, avenue Henri Poincaré, F-59652 Villeneuve d'Ascq, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Théron
authors.affiliation: CBMN, allée Geoffroy Saint Hilaire, Bât. B14, F-33600 Pessac, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Aimé
keywords: Atomic force microscopy (AFM); Block copolymers; High frequency AFM probe; Micro electromechanical resonators; Micro electromechanical systems (MEMS)