Scanning probe microscope and method for obtaining topographic image, surface potential image, and electrostatic capacitance distribution image

摘要

A scanning probe microscope used for obtaining a surface topographical image, a surface potential image and an electrostatic capacitance distribution includes a probe having a tip attached to a lever, an oscillator for oscillating the probe in close proximity to a specimen, a displacement detector for detecting the probe oscillations and outputting a displacement signal in accordance therewith, a positioning device for relative positioning of the probe tip with respect to the specimen in the X and Y directions and for controlling the distance between the probe tip and the specimen in the Z direction, an AC voltage source for applying an AC voltage between the probe to oscillate the probe at a composite frequency having components at and 2 , a DC voltage source for applying a DC voltage between the probe and the specimen to maintain the amplitude component of the probe oscillation at zero to enable the calculation of a surface potential of the specimen in accordance with the DC voltage and to enable the calculation of an electrostatic capacitance between the specimen and the probe in accordance with the 2 amplitude component of the probe oscillation, and a display device responsive to the phase difference between an output of the oscillator and the displacement signal for indicating when the probe collides with the surface of the specimen.