Tapping-mode atomic force microscopy and phase-imaging in higher eigenmodes

Tapping-mode atomic force microscopy (TM-AFM) is a powerful tool to study s oft biological samples. Higher eigenmodes of the vibrating cantilever offer enhanced signal and smaller time constants increasing the sensitivity of t he tapping probe as compared to conventional TM-AFM. The first five eigenmo des of a upsilon-shaped silicon cantilever were investigated with respect t o their suitability for imaging. Stable imaging was possible in the first a nd third modes. Phase imaging in the third mode was extremely sensitive to surface inhomogeneities and surface contamination particles not visible in standard TM-AFM. (C) 1999 American Institute of Physics. [S0003-6951(99)012 22-X].