Piezo stack fabrication and characterization for scanning probe microscopy*

A scanning probe microscope (SPM) must accurately move a tiny sensor across a macroscopic distance to approach within a few nanometers of a sample surface. A typical SPM employs a stepper motor composed of piezoelectric shear actuators, in which individual piezo plates are combined in stacks to increase their total shear. Although pre-fabricated piezo stacks are commercially available, they are typically costly, especially when custom dimensions are required to fit a novel microscope design. Here we describe a procedure to reliably fabricate arbitrary-sized stacks of soft lead zirconate titanate (PZT) piezo ceramic plates. To verify the reproducibility of our procedure, we designed a capacitance sensing unit that can measure the shear of each stack with 50 nanometer accuracy . We confirm our capacitive characterization with a Michelson interferometer.