TAPPING MODE ATOMIC-FORCE MICROSCOPY USING ELECTROSTATIC FORCE MODULATION

We have developed a simple tapping mode in atomic force microscopy usi ng a capacitive electrostatic force. In this technique, the probe-to-s ample distance is modulated by the capacitive force between tip and sa mple induced by a sinusoidal bias applied to the conductive probe inst ead of a conventional mechanical vibration. The electrostatic force ve rsus distance curve of the probe indicates that it is necessary to use a rather stiff cantilever to prevent the snapping of the tip into the surface due to the adhesive force at the surface. We have succeeded i n obtaining topographic images of a conductive surface as well as a so ft polystyrene sample with a low tracking and lateral force through th is method. (C) 1996 American Institute of Physics.