Atomic force microscope cantilever calibration using a focused ion beam.

Area of Science:

• Materials Science
• Nanotechnology
• Metrology

Background:

• Accurate determination of atomic force microscope (AFM) cantilever spring constants is critical for quantitative nanoscience.
• Established methods like the Cleveland added mass technique suffer from uncertainties in mass estimation.
• The focused ion beam (FIB) offers precise material manipulation capabilities.

Purpose of the Study:

• To develop a modified calibration method for AFM cantilever spring constants.
• To reduce uncertainty in the added mass technique by precisely controlling mass removal.
• To validate the new method and assess its impact on cantilever performance.

Main Methods:

• Modification of the Cleveland added mass technique using a focused ion beam (FIB).
• Precise removal of a defined volume from AFM cantilevers with known density.
• Extensive testing to verify method assumptions and compare with other calibration techniques.

Main Results:

• Achieved typical uncertainties between 7% and 10% for silicon cantilevers with spring constants > 0.7 N/m.
• Demonstrated that FIB modification does not impair the cantilever's data acquisition capabilities.
• Identified practical improvements for other calibration methods and insights into FIB-modified cantilevers.

Conclusions:

• The FIB-based mass reduction technique provides a more accurate calibration for AFM cantilevers.
• This method is applicable to various AFM cantilevers, especially silicon ones, for high-precision measurements.
• The technique is valuable for nanoscience research requiring pristine AFM tip conditions.