A moving window correlation method to reduce the distortion of scanning probe microscope images

Area of Science:

• Materials Science
• Nanotechnology
• Instrumentation

Background:

• Scanning probe microscopy (SPM), including scanning tunneling microscopy (STM) and atomic force microscopy (AFM), relies on piezoelectric actuators for surface scanning.
• Open-loop operation of piezoelectric actuators introduces nonlinearities, primarily hysteresis and drift, which degrade positioning accuracy and image quality.

Purpose of the Study:

• To develop and present a novel method for quantifying hysteresis in piezoelectric actuators.
• To improve the accuracy of surface scans generated by SPM instruments.
• To reduce image distortions caused by actuator nonlinearities.

Main Methods:

• A moving window correlation method is proposed to analyze trace and retrace profiles.
• Correlation is performed between data within imposed windows on both profiles to identify corresponding pixel pairs.
• The method identifies pixel pairs at the same physical position along the fast scanning axis (x).
• Calculated x-distances between pixel pairs are used in a correction scheme.

Main Results:

• The moving window correlation method effectively quantifies hysteresis in piezoelectric actuators.
• The proposed correction scheme successfully reduces image distortions.
• Improved positioning accuracy is achieved through the correction of nonlinearities.

Conclusions:

• The moving window correlation method offers a viable solution for addressing hysteresis in piezoelectric actuators.
• This technique enhances the reliability and accuracy of SPM imaging.
• The findings contribute to the advancement of high-resolution surface analysis techniques.