DETECTING APPARATUS OF VERY SMALL DISPLACEMENT, PIEZOELECTRIC ACTUATOR HAVING THIS DETECTING APPARATUS AND SCANNING PROBE MICROSCOPE HAVING THIS PIEZOELECTRIC ACTUATOR

摘要

PURPOSE:To correctly detect a very little amount of displacement with good accuracy thereby to measure the shape of the surface of a sample more minutely and correctly by measuring a reference sample at an atomic level which changes its state every predetermined distance. CONSTITUTION:A voltage of an opposite polarity corresponding to the difference of a tunnel current flowing between a scanning probe 14 and a sample 12 from a reference valve is impressed to a piezoelectric actuator 16, so that the distance between the probe 14 and sample 12 is kept constant. A bias voltage is impressed between a position detecting probe 22 and a reference sample 26 by a power source V2, and therefore a tunnel current flows therebetween. The displacement amount of the probe 14 scanning the surface of the sample 12 is output by the vertical movement of the probe 22 along the surface of the sample 26 in accordance with the displacement of the actuator 16, and measured on the basis of the waveform of the tunnel current.