Phase modulation dynamic AFM measurement system based on tuning fork probe

Abstract

In this paper, we design a phase modulation dynamic AFM measurement system based on the characteristics of the novel tuning fork probe. The AFM head based on the tuning fork probe can work cooperatively with the displacement positioning platform driven by the piezoelectric actuators to achieve the feedback in z direction. The large range nanometer positioning stage can be used to scan the sample in x and y directions. With nanoscale resolution, the whole system has a range of 25mm×25mm in horizontal. The measurement data can be traced back to the definition of meter through three embedded laser interferometers. We measure the internal working current of the tuning fork by experiment, and gain the electro-mechanical coupling factor of the probe, and achieve the calibration of AFM head. To guarantee the system’s feasibility, the AFM measuring system accomplishes the measurement of typical grid structure’s surface morphology in phase modulation mode.