The impact on image formation of inevitable tip bending with modern high resolution atomic force microscopy probes

The majority of atomic force microscopy (AFM) applications rely on tracking and analysing the cantilever motion while assuming the tip is a solid attachment. This assumption is insufficient for accurate imaging with very high aspect ratio (>10 : 1) probes, where tip bending, in addition to cantilever deflection, can significantly distort the morphological image. Here, using quantitative imaging on reference nanostructures and experimental calibration of the tip stiffness, we show that tip bending plays an important role for a range of tested popular commercial AFM probes, even those with relatively low tip aspect ratio, and results in greater than 10 nm errors in measured sample topography in the presence of sufficient tip-sample interaction forces. These effects can be significantly altered by changing the imaging environment. We propose that tip bending should be properly considered in all AFM applications and included in image analysis pipelines to ensure accurate topographic characterisation.