Nanoindentation and contact stiffness measurement using force modulation with a capacitive load-displacement transducer

We have implemented a force modulation technique for nanoindentation using a three-plate capacitive load-displacement transducer. The stiffness sensit ivity of the instrument is similar to 0.1 N/m. We show that the sensitivity of this instrument is sufficient to detect long-range surface forces and t o locate the surface of a specimen. The low spring mass (236 mg), spring co nstant (116 N/m), and damping coefficient (0.008 Ns/m) of the transducer al lows measurement of the damping losses for nanoscale contacts. We present t he experimental technique, important specimen mounting information, and sys tem calibration for nanomechanical property measurement. (C) 1999 American Institute of Physics. [S0034-6748(99)04105-2].