ELECTROSTATIC FORCE MICROSCOPE IMAGING ANALYZED BY THE SURFACE-CHARGEMETHOD

The electrostatic force acting between the probe of the force microsco pe and the sample surface is theoretically investigated by using the s urface charge method. The actual shapes of the probe (an etched tungst en wire) and the sample (gratinglike electrodes) which are used in the experiments are considered to calculate the electrostatic forces quan titatively. It is shown that the macroscopic probe has to be taken int o account for the force measurement. However, only the top part of the probe is responsive for the measurement of the force gradient. The im aging properties through the detection of the electrostatic force are also investigated experimentally by using the dynamic (ac) mode force microscope. The potentiometric and topographic effects on the imaging are discussed on the basis of theoretical calculations and the experim ental results.