Electrostatic force microscope


A type of scanning probe microscope.  It is a microscope that scans the probe and measures the electrostatic force which works between the probe and the specimen, and draws images based on the measurements.

The electrostatic force microscope is a kind of scanning probe microscopes and measures the electrostatic force as a physical quantity. It is also called as scanning capacitance microscope. When voltage V is applied between the probe and the measured object, electrostatic force f working between them is proportional to the partial derivative of the energy obtained by multiplying the square of the voltage with capacitance C between the probe and the object, taken with respect to the perpendicular distance z. Hence, f=∂(C・V2/2)/∂z. Therefore, if the voltage is kept a constant value, the capacitance can be obtained from the force generated. At present, measurement with the resolution of 10-21 F at a bandwidth of 1 Hz is possible. Moreover when the probe is grounded and the electrostatic force and the distance are measured, the voltage can be obtained. Such method as providing electric charges and obtaining the change in time from the change of the electrostatic force is also developed. Moreover, by measuring capacitance while varying the bias voltage, the status of dopants, in a semiconductor can also be known. Thus this apparatus is useful to know local electrical characteristics of micro circuitry.


[Related Terms]
Scanning tunneling microscope (STM)