Texas Instruments Corporation

Hal Edwards

Walter Marvin Duncan

An embodiment of the instant invention is a scanning-probe microscope for measuring the topography of a surface of a sample, the scanning-probe microscope comprising: an XYZ piezo drive (piezo drive 1); a quartz tuning-fork oscillator (fork 2) having a first electrode (electrode 3 or 4) and a second electrode (electrode 3 or 4), wherein the quartz tuning-fork oscillator is attached to the XYZ piezo drive, and wherein the quartz tuning-fork oscillator is oriented such that the tines of the quartz tuning-fork oscillator each lie in the XY plane and their fundamental mode of oscillation vibrates the ends of the tines in the Z direction; a probe tip (probe tip 6) affixed to one of the tines, the probe tip comes to a point in the Z direction and directed away from the XYZ piezo drive; a signal source (source 7) to provide a drive signal to drive the first electrode at a mechanical resonant frequency of the quartz tuning-fork oscillator; a current-to-voltage amplifier (preamp 8) to monitor the electrical current flowing through the second electrode and having an output, wherein the electrical impedance of the quartz tuning-fork oscillator may be measured, and the resonant vibration amplitude of the quartz tuning-fork oscillator is monitored; and wherein the XYZ piezo drive is operable to move the probe tip close to the surface of the sample until the probe tip lightly taps the sample surface thereby decreasing and oscillation amplitude the electrical impedance of the quartz tuning-fork oscillator and wherein the interaction between the probe tip and the sample surface can be used to regulate the distance between the probe tip and the sample surface.

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Garland, TX, United States of America

Hal Edwards