TIP-SAMPLE INTERACTIONS IN SCANNING FORCE MICROSCOPY USING THE FREQUENCY-MODULATION TECHNIQUE - EXPERIMENTS AND COMPUTER-SIMULATION

The resonance frequency and the damping behaviour of a vibrating canti lever as used in dynamic Scanning Force Microscopy (SFM) is investigat ed with the frequency modulation (FM) technique. The properties of a s ilicon-cantilever/tip vibrating in front of a silicon surface were stu died under UHV conditions as a function of the tip-sample distance. Th e experimental results are compared with a computer simulation. The di fferent characteristic parts of the experimental curves can be interpr eted in terms of attractive and repulsive forces acting on the cantile ver as well as the behaviour of the amplitude control electronics. Usi ng the computer simulation noncontact regimes can clearly be distingui shed from intermittent contact regimes.