Patent ID: 7360404

Claim:
A method for examining a sample surface using an atomic force scanning microscope comprising a cantilever with a longitudinal extension along which a measuring tip is disposed, which is located relative to said sample surface by a means for driving and having a spatial position detected with a sensor, and at least one ultrasound generator, which initiates vibration excitation at an excitation frequency between said sample surface and said cantilever, the measuring tip being brought into contact with said sample surface so that said measuring tip is excited to vibrations oriented lateral to said sample surface and perpendicular to said longitudinal extension of said cantilever, torsional vibrations being induced in said cantilever which are detected and analyzed by an evaluation unit, said vibration excitation causing oscillations of said measuring tip including harmonic vibrations relative to the excitation frequency and said vibration excitation includes excitation amplitudes which cause torsional amplitudes within the cantilever with maximum values thereof forming a plateau of resonance spectra despite increasing excitation amplitudes and the resonance spectra which undergoes, in a range of said maximum values of said torsional amplitudes, a widening which is determinable by a plateau width, comprising: using at least one of the plateau of said resonance spectra, a width of the plateau of said resonance spectra and/or a gradient of said resonance spectra for examining said sample surface.