DESIGN AND CALIBRATION OF A SCANNING FORCE MICROSCOPE FOR FRICTION, ADHESION, AND CONTACT POTENTIAL STUDIES

We present the design and calibration of a scanning force microscope w hich can be used to study friction, adhesion, and contact potential di fferences between the cantilever tip and surface. The microscope uses a modular design where the laser, cantilever/sample holder, reflecting minor, and detector are mounted directly on an optical table. The las er, reflecting mirror, and detector are mounted on translation and rot ation stages. With this design the components can be rearranged to cal ibrate the Z piezo motion as a function of applied voltage. Using the detector micrometers, the detector response (voltage-to-distance relat ionship) can be determined after each series of measurements. The cant ilever/sample holder is constructed such that the components are mater ial matched and thermally compensated from a common reference point. T his design feature minimizes thermal drift of the instrument. The inst rument can be used in a contact scanning mode where both normal and la teral deflections of the cantilever are measured. In addition, the ins trument can be used in frictional force studies, force curve mapping o f the surface, and contact potential measurements. We present examples of each, including a detailed account of the instrument design and ca libration. (C) 1995 American Institute of Physics.