Jon R. Pratt, John A. Kramar, Gordon A. Shaw, Lee Kumanchik
We describe the electrical and length measurements necessary to realize micronewton forces in a fashion consistent with the International System of Units (SI). We first discuss instrumentation and procedures required to accurately characterize an electrical force. This topic is discussed within the context of the National Institute of Standards and Technology (NIST) electrostatic force balance, a primary reference instrument system where comparisons between deadweight and electrostatic forces have been performed at the level of several micronewtons. We share recent results obtained with this instrument that demonstrate agreement between electrical and deadweight forces that are consistent with the uncertainties in mg mass artifacts, which are a few parts in 105. Extending these measurement principles to a microscale device, we propose a method to apply electrostatic forces directly to a conductive atomic force microscope probe. We describe procedures to measure the capacitance gradient between such a probe and a conductive substrate, and how this quantitative information might be used to produce an SI traceable, insitu calibration of the force sensitivity of the device.
Proceedings of the 2006 SEM Annual Conference & Exposition
June 4-7, 2006
St. Louis, MO, USA
2006 SEM Annual Conference & Exposition
atomic force microscopy, cantilever spring constant measurement, standard references and practices