Methods for vertical drift measurements of scanning probe microscopes

Area of Science:

• Scientific instrumentation
• Surface science and metrology

Background:

• Time stability is critical for scanning probe microscope (SPM) applications.
• While closed-loop systems minimize drift, residual lateral and vertical drift persist.
• Existing methods for measuring lateral drift are well-established, but vertical drift measurement is challenging due to coupling effects.

Purpose of the Study:

• To develop and validate a novel method for measuring vertical drift in SPMs.
• To address the challenge of isolating and quantifying vertical drift, considering lateral drift influences.
• To provide a means for evaluating the vertical instability of SPM instruments.

Main Methods:

• A new method based on analyzing scanned topography images is proposed.
• The technique explicitly incorporates the influence of lateral drift into the vertical drift calculation.
• Experimental validation was performed using the developed method.

Main Results:

• The vertical drift of SPM instruments is demonstrated to be non-negligible.
• Vertical drift is found to vary across different pixels within a single scanned image.
• The proposed method successfully revealed and quantified pixel-specific vertical drift.

Conclusions:

• The developed method provides an effective means to measure vertical drift in SPMs.
• Understanding and quantifying vertical drift is essential for improving SPM accuracy and reliability.
• This work highlights the importance of evaluating vertical instrument instability for advanced SPM applications.