The Kelvin probe force microscope (KFM) is a useful tool that measures
the surface potentials of both conducting and nonconducting materials
. Recently, we have succeeded in improving the accuracy of potential m
easurements and increased the lateral resolution of the topographic im
age. Furthermore, Z axis servo control was improved to prevent the tip
from coming into contact with the sample surface during scanning. Fin
ally, the force gradient between the tip and the sample became steeper
during the acquisition of the topographic image due to the inactivati
on of the modulation AC voltage. As a result, the potential resolution
was less than 1 mV and the lateral resolution of the topographic imag
e was improved to as high as 10 nm.