SU1704191A1 - Method of control over speed of scanning of tunnel microscope and device to implement it - Google Patents

Abstract

The invention relates to tunneling microscopy and can be used in tunneling microscopes, profilometers and measuring instruments. The aim of the invention is to reduce the measurement time. The method consists in the fact that the horizontal scanning speed of the tips on the sample surface depends on the surface relief, so that this speed decreases if the lifting speed of the sample under the tip exceeds the maximum lifting speed of the tip, and increases in the opposite case. The device contains a differentiator 1, a shaper 2 of the signal module, a source 3 of the setup signal, a differential amplifier 4. The signal from the height stabilization system of the tip of the tunnel microscope is fed to the input of the device, and its rate of change is compared with the setpoint signal using a differential amplifier 4. At the output of the limiter 5 a signal is generated that controls the sweep speed, and the frame scan time is not limited by the maximum speed allowed at the worst point of the sample. 2 s. And 2 z. P. f-ly, 3 ill. Yo

Description

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Claims (4)

Claim 1. A method of controlling the scanning speed of a tunneling microscope, including the movement of the tip in the xy plane of the sample in the direction T with the speed of the tip in the ζ direction perpendicular to the plane of the sample, so that a gap is maintained between the tip and the uneven surface of the sample, characterized in that, in order to reduce time measurements, the module of speed support equal to value .7? . ! 1 ‘/ | IVZmSKtJ? ag where VfmaKc. Vzmaxc are the maximum tip speeds in the directions? And ζ, respectively, limited by the speed of the drive, m / s; h (х.у) - ζ - coordinate of the surface of the sample at the point х.у. m: T is a unit vector lying in the plane (x, y) and defining the direction of the velocity of the tip in the plane (xy) at the point xy, m; Eb (xy) is a derivative in the direction [(dimensionless). 2. Device for controlling the scanning speed of a tunneling microscope. containing the first drive for the movement of the tip along the x-axis of the sample plane (xy). the second drive for the movement of the tip along the ζ axis. perpendicular to the plane (xy), the sensor ζ - coordinates of the tip, as well as the speed control of the tip in the plane (xy), characterized in that. that, in order to reduce the measurement time, a series-connected differentiator, a signal module driver, a differential amplifier, an amplitude limiter, as well as a setpoint signal source, the output of which is connected to the second input of the differential amplifier, the input of the differentiator connected to the output of the sensor z are the coordinates of the tip, and the output of the amplitude 5 limiter is connected to the drive of the z-coordinate of the tip. 3. The device according to claim 2, characterized in that, in order to increase the accuracy of measurements when using the piezoelectric drive of the tip, the differentiator is made in the form of a current amplifier, the inputs of which are included in the open circuit of one of the terminals of the piezoelectric drive of the tip for movement along the z axis . 4. The device according to claim 2, characterized in that. that, in order to expand the functionality by obtaining additional information about the roughness parameters of the sample, a signal comparator is introduced into it, one of the inputs of which is connected to the input of the limiter, and the other to the output of the limiter, while the output of the device is the output of the comparator. X * (±) x (t)