Compact two-dimensional coarse-positioner for scanning probe microscopes

We report on the design and fabrication of a compact two-dimensional xy-positioner for scanning probe microscopes. This positioner uses three piezoelectric bimorphs in flexing or length-change mode by appropriate selection of electrodes and voltage polarities. One end of these bimorphs is fixed to a rectangular metal frame while on each of the free ends two sapphire disks are fixed which can slide against the polished plates of a platform movable in the xy-plane. For moving the platform by one step, the bimorphs are deformed sequentially in one mode and they are brought back to their undeformed state simultaneously. The motion of the positioner has been tested with an optical microscope and a homemade scanning tunneling microscope.