JPH0650706A - Fine movement mechanism of scanning tunneling microscope - Google Patents

Abstract

(57) [Abstract] [Purpose] In the fine movement mechanism of the STM, in three piezoelectric elements arranged in orthogonal three-dimensional directions, even if each piezoelectric element expands and contracts and the probe moves, the effect in the other two directions Do not receive Further, the precision of the probe movement amount by the fine movement mechanism is improved. [Structure] Piezoelectric elements 2A and 2B for scanning a probe 3 arranged so as to face the sample measurement surface along with the support member 8 along the measurement surface, and a piezoelectric element 2C for finely moving in the axial direction thereof. The three piezoelectric elements are coupled to the support member in a positional relationship orthogonal to each other, and at the coupling points between each of the piezoelectric elements and the support member, there is high rigidity that does not cause deformation in the operation direction of each piezoelectric element. It is configured to dispose the coupling members 10A to 10C having low rigidity in which deformation easily occurs in the operation directions of the other two piezoelectric elements orthogonal to the operation direction. The coupling member has, for example, a two-tiered parallel plate structure. Further, control means 2 for controlling the amount of movement of the piezoelectric element
5 and the displacement detecting means 20z1 to 20z4, 23 attached to the portion of the coupling member having low rigidity, and a feedback control system is provided for controlling the operation of the piezoelectric element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine movement mechanism of a scanning tunnel microscope, and more particularly to a scanning tunnel microscope used for observing, measuring or manipulating an extremely fine atomic level object by utilizing a tunnel current. And a tripod type fine movement mechanism suitable for changing the position of the probe and adapted to accurately move the probe position to a desired position.

[0002]

2. Description of the Related Art A scanning tunneling microscope (hereinafter referred to as "STM") is used, for example, for measuring atomic level irregularities on a sample surface. In STM, the probe facing the sample is
It is arranged with its axis perpendicular to the sample surface.
When this probe measures the sample surface, a tunnel current flowing between the tip of the probe and the sample surface is used. The position of the probe is adjusted so as to approach the sample surface at a fine distance on an atomic level in order to allow a constant tunneling current to flow between the two substances. The fine adjustment mechanism adjusts the position of the probe.

In order to maintain a constant distance between the sample surface and the probe, the fine movement mechanism of the probe keeps the constant distance by moving the probe in the height direction (Z direction) according to the unevenness of the sample surface. And a piezoelectric element for scanning for moving the probe in a direction (X, Y direction) parallel to the sample surface. With this fine movement mechanism, the probe is moved along the sample surface while maintaining a constant distance from the sample surface, and the unevenness state of the sample surface is measured based on the control amount required for movement control of the probe. .

There are various kinds of STM probe fine movement mechanisms, as described in the literature "Precision Positioning Technology", Minoru Izawa, Industrial Research Society (1989), Tables 1 and 2 on page 250.
Among them, the tripod format is widely used in STM. An example thereof is shown in FIG.

In FIG. 9, reference numeral 1 is a base member for fixing the fine movement mechanism to the main body. The base member 1 is attached to the main body such as the coarse movement mechanism of the STM by using a fixing means (not shown). 2A, 2B, and 2C are rod-shaped piezoelectric elements. In FIG. 9, two piezoelectric elements 2A and 2B located in front of the base member 1 are actuators for scanning the probe 3. The piezoelectric elements 2A and 2B have their axial directions orthogonal to each other. The piezoelectric element 2C arranged at the rear position of the base member 1 is an actuator for finely moving (advancing / retracting) the probe 3 in its axial direction.
Each of the piezoelectric elements 2A, 2B, 2C is formed of a structure in which piezoelectric elements are laminated so that a required amount of expansion / contraction occurs. The base member 1 has a substantially L-shape as a whole, and a piece 1 for supporting and fixing the lower ends of the piezoelectric elements 2A and 2B to the front edge.
a and 1b are formed, and an upright piece 1c for supporting and fixing the rear end of the piezoelectric element 2C is formed at the rear edge.

Piezoelectric elements 2A, 2B, 2C in the base member 1
In the arrangement state, the piezoelectric elements 2A and 2B are arranged such that their expansion and contraction directions are orthogonal to each other, the axial direction of the piezoelectric element 2C is the same as the axial direction of the probe 3, and the piezoelectric element 2C expands and contracts. The directions are orthogonal to the expansion and contraction directions of the piezoelectric elements 2A and 2B. In FIG. 9, reference numerals 4A to 4C are power supply lines that supply a driving voltage to each of the piezoelectric elements 2A to 2C.

The probe 3 is arranged so that its tip end faces the front side in FIG. 9, and is fixed to the probe mounting portion 5 with a screw 6. The probe 3 and the probe mounting portion 5 are formed of a conductive member. The line 7 connected to the probe attachment part 5 is
It is a power supply line for applying a voltage for flowing a tunnel current to the probe 3. The tunnel current flows between the probe and the sample when the distance between the probe 3 and the measurement surface of the sample reaches a predetermined fine distance at the atomic level.

As other configurations of the STM, a voltage source for generating an applied voltage, a detection circuit for detecting a tunnel current flowing through the probe 3, and a probe circuit for the sample measurement surface in order to keep the tunnel current flowing constant. Configuration of electrical system such as a probe position control circuit unit for adjusting the distance to a constant value, a scanning unit for scanning the probe along the sample measurement surface, and a calculation unit for collecting and processing data regarding the position change of the probe 3. With elements. Illustrations of these components are omitted because they have little relation to the main part of the present invention.

Reference numeral 8 is a support member for supporting the probe mounting portion 5, and the support member 8 is formed of an insulator. Piezoelectric element 2
The other end of each of A to 2C is coupled to the lower surface of the support member 8. The probe mounting portion 5 is fixed on the support member 8 with an adhesive. The function of the support member 8 is to electrically disconnect between the probe mounting portion 5 through which the tunnel current flows and the piezoelectric elements 2A to 2C that expand and contract under the action of the drive voltage.

[0010]

The problem of the tripod type fine movement mechanism shown in FIG. 9 will be described with reference to FIGS. 10 and 11. Corresponding to the expansion and contraction directions of the piezoelectric elements 2A, 2B, 2C, three axes X, Y, which are orthogonal to each other as shown in FIG.
Define each direction of Z. In the above positional relationship, when the piezoelectric element 2C is expanded and contracted to move the probe 3 in the Z direction, the probe 3 also moves in each of the X and Y directions.

FIG. 10 and FIG. 11 are views showing the states of the probe 3 before and after deformation when the piezoelectric element 2C is expanded, as viewed from the side. It is assumed that the axial direction of the probe 3 is parallel to the Z direction before the piezoelectric element 2C extends. In this state, the distance between the probe 3 and the sample surface can be known accurately. Next, assume that the piezoelectric element 2C extends in the Z direction by a predetermined amount. In this case, the support member 8 supporting the probe mounting portion 5 tries to move to the left due to the extension of the piezoelectric element 2C, but since the lower portion thereof is supported by the other two scanning piezoelectric elements 2A and 2B. , Piezoelectric element 2
Bending deformation occurs in A and 2B. As a result, the head portion including the supporting member 8 changes its posture so as to be inclined by θ as shown in FIG. 11. By this change in posture, the probe 3
11 is displaced by ΔZ in the Z direction and is displaced by Δh in the vertical direction in FIG. In FIG. 11, a point P1 is the tip position of the probe 3 before deformation.

In the above case, since the piezoelectric elements 2A and 2B are inclined by 45 degrees with respect to the paper surface, the displacements in the X and Y directions are Δh / (2 ^1/2 ).

As is apparent from the above description, the piezoelectric element 2C
When the probe 3 is moved in the Z direction by the above, there is a problem that the tip of the probe is displaced in the X direction and the Y direction. In the actual measurement on the sample measurement surface, the probe 3 always finely moves in the Z direction so as to trace the unevenness of the sample surface due to the expansion and contraction of the piezoelectric element 2C. As a result, the tip of the probe 3 is
X regardless of the XY scanning operation by the piezoelectric elements 2A and 2B.
It moves slightly in the Y and Y directions. Such a minute movement in each of the X and Y directions due to the movement of the probe 3 in the Z direction causes an error in the XY coordinate value, which becomes a distortion element of the obtained STM image.

Also, when either of the piezoelectric elements 2A and 2B is expanded or contracted, the tip of the probe 3 causes a minute displacement in a direction other than the originally desired direction by the same action as described above. That is, when the piezoelectric element 2A is moved in the X direction,
At the tip of the probe, a slight displacement occurs in the Y and Z directions by Δh. When the piezoelectric element 2B is moved in the Y direction, the tip of the probe is slightly displaced by Δh in each of the X and Z directions.

Further, as a general problem, in the case where each piezoelectric element of the probe fine movement mechanism is driven to move the probe in a desired direction, conventionally, a desired amount of movement is accurately generated in the probe. It was unclear whether or not there was. Therefore, it has been conventionally demanded to improve the accuracy of the probe movement amount by the fine movement mechanism.

In view of the above problems, the first object of the present invention is to provide one of the three piezoelectric elements provided for moving the probe in each of the three-dimensional directions orthogonal to each other. Even if it expands and contracts and moves the probe in one direction,
It is to provide a fine movement mechanism of an STM that is not affected by the influence in the remaining two directions and does not cause displacement.

A second object of the present invention is to provide a fine movement mechanism of an STM having a control system for improving the accuracy of the probe movement amount by the fine movement mechanism by utilizing the constitution for achieving the above first purpose. Especially.

[0018]

A fine movement mechanism of an STM according to the present invention includes a probe arranged so that its tip faces a measurement surface of a sample while being supported by a support member, and a support member. Three piezoelectric elements provided with two piezoelectric elements for scanning the probe supported along with the support member along the measurement surface and piezoelectric elements for similarly finely moving the probe in its axial direction. However, it has a configuration in which the respective operation directions are coupled to the support member in a positional relationship orthogonal to each other, and there is no deformation in the operation direction of each piezoelectric element at the location where the three piezoelectric elements are coupled to the support member. It has high rigidity that does not occur,
It is configured to dispose a coupling member having low rigidity in which deformation easily occurs in the operation directions of the other two piezoelectric elements orthogonal to the operation direction.

In the above structure, preferably, the coupling member has a parallel plate structure having a deformability in a first direction and a parallel plate structure having a deformability in a second direction orthogonal to the first direction. Are overlapped with each other in the expansion / contraction operation direction of the corresponding piezoelectric element.

In the above structure, preferably, the connecting member has a two-stage parallel plate structure.

In the above construction, preferably, the control means for controlling the operation amount of the piezoelectric element and the displacement detecting means attached to the portion of the coupling member having a low rigidity are provided, and the displacement amount output from the displacement detecting means is adjusted. By inputting such a detection signal to the control means, a feedback control system is provided for controlling the operation of the piezoelectric element.

In the above structure, preferably, the displacement detecting means is a bridge circuit composed of a strain gauge arranged on the deformable surface of the coupling member.

[0023]

In the fine movement mechanism of the STM according to the present invention, the joint between each piezoelectric element and the probe supporting member has a high rigidity in the operating direction of the piezoelectric element, such as a two-stage parallel plate structure. , By interposing a coupling member having low rigidity in the operation directions of the other two piezoelectric elements orthogonal to this operation direction, the probe is moved in one necessary direction, and displacement is made in the other directions. I tried not to generate it. This makes it possible to accurately move the tip of the probe in a desired direction.

Further, by utilizing the structure of the above-mentioned coupling member, a predetermined number of strain gauges or the like are provided in the deformed portion which is easily deformed,
Moreover, a bridge circuit is assembled using this strain gauge, and when the coupling member is deformed, the deformation amount is detected and the probe movement amount is detected. By utilizing the configuration of this detection circuit and returning the detection signal of the detection circuit to the control means for controlling the expansion / contraction operation of the piezoelectric element, a feedback control system is configured. This improves the accuracy of the probe movement amount due to the operation of the fine movement mechanism.

[0025]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a perspective view of a fine movement mechanism of an STM according to the present invention, which is a view similar to FIG. 9 described above, and FIG. 2 is a side view of the fine movement mechanism. In FIG. 1, the same reference numerals are given to the elements described in FIG. Further, as shown in FIG. 1, each direction of three axes X, Y, and Z orthogonal to each other is defined.

Reference numeral 1 is a base member, 2A, 2B and 2C are rod-shaped piezoelectric elements for fine movement, and 3 is a probe. The base member 1 is a member for fixing the fine movement mechanism to the main body. Each piezoelectric element 2A, 2B, 2C expands and contracts in the axial direction by controlling the magnitude of the applied voltage. The operation amount of the expansion / contraction operation is a minute amount for moving the probe 3 corresponding to the atomic level unevenness of the measurement surface of the sample. For each piezoelectric element, the axial direction in which the expansion / contraction effect occurs is the operating direction of the piezoelectric element. Each piezoelectric element is formed by stacking a large number of element elements having a small amount of expansion and contraction. Probe 3
Is a conductive needle.

The probe 3 is arranged so that its tip faces the measurement surface of the sample (not shown) and faces the measurement surface. The probe 3 is fixed at its base end to the probe mounting portion 5 by using a screw 6. The probe mounting portion 5 is formed of a conductive member. The line 7 connected to the probe mounting portion 5 is connected to the probe 3
This is a power supply line that applies an applied voltage for causing a tunnel current to flow through. 8 is a support member for fixing the probe mounting portion 5,
It is a member that supports the probe 3. One end of each of the piezoelectric elements 2A to 2C is coupled to the corresponding portion of the lower surface of the support member 8 via coupling members 10A to 10C.

The two piezoelectric elements 2A and 2B are connected to the probe 3 in the X direction.
The piezoelectric element 2C is an actuator for scanning in the Y direction, and is an actuator for finely moving the probe 3 in its axial direction (Z direction) in order to adjust the distance between the probe 3 and the sample. The piezoelectric elements 2A and 2B move the tip of the probe 3 parallel to the sample measurement surface. The piezoelectric element 2C is arranged so that its axial direction is parallel to the axial direction of the probe 3. The piezoelectric element 2A has its operation direction oriented in the X direction, the piezoelectric element 2B has its operation direction oriented in the Y direction, and the piezoelectric element 2C has its operation direction oriented in the Z direction. The three piezoelectric elements 2A to 2C are arranged so that their operation directions are orthogonal to each other.

In the base member 1, the piece 1 at the front edge thereof
a and 1b fix and support the lower ends of the piezoelectric elements 2A and 2B, respectively, and the trailing edge piece 1c fixes and supports the rear end of the piezoelectric element 2C. As described above, the other ends of the piezoelectric elements 2A to 2C are respectively coupled to the corresponding positions on the lower surface of the support member 8 via the coupling members 10A to 10C. In the arrangement state of the piezoelectric elements 2A to 2C in the base member 1, the axial direction of the piezoelectric element 2C is the Z direction, and the piezoelectric element 2
A and 2B are arranged so that their axial directions are orthogonal to each other in the XY plane and orthogonal to the axial direction of the piezoelectric element 2C. In FIG. 1, 4A to 4C are piezoelectric elements 2A to 2C.
It is a power supply line that supplies a drive voltage to each of C.

The working relationship between the above-mentioned coupling members 10A to 10C, the coupling members 10A to 10C and the piezoelectric elements 2A to 2C will be described in detail.

FIG. 4 shows an example of the structure of the connecting member 10A as a representative. The structures of the coupling members 10B and 10C are basically the same. In FIG. 4, the coupling member 10A has a so-called parallel plate structure, and in particular, the illustrated example shows a two-stage parallel plate structure. Coupling member 10A
Has its lower surface fixed to the end of the piezoelectric element 2A on the support member 8 side, and its upper surface 11 fixed to the lower surface of the support member 8. The coupling member 10A is in the X direction, that is, the piezoelectric element 2A.
Parallel flat plate structure part 1 provided in two layers in the direction of expansion and contraction of
It has 2a and 12b. In the parallel plate structure portion 12a, two thin flat plates 13 are formed in parallel, and the parallel plate structure portion 12
In b, two thin flat plates 14 are formed in parallel. Flat plate 1
3 is arranged so as to be orthogonal to the Y direction, and the flat plate 14 is arranged so as to be orthogonal to the Z direction. In the coupling member 10A, the flat plate 13 and the flat plate 14 are formed so as to be orthogonal to each other. In FIG. 4, 15 is an end rigid body portion, and 16 is an intermediate rigid body portion. The coupling member 10A having such a structure is integrally formed.

Based on the above structure, the connecting member 10A is
It does not deform in the X direction, has high rigidity, is easily deformed flexibly in the Y direction due to the deformation characteristics of the parallel plate structure 12a, and is deformed in the Z direction due to the deformation characteristics of the parallel plate structure 12b. easy. In other words, the connecting member 10A
Has a high rigidity in the X direction, which is the expansion / contraction direction of the piezoelectric element 2A, and a low rigidity that is easily deformed in the Y and Z directions orthogonal to the X direction.

The structures of the coupling members 10B and 10C are the same. The difference is that the direction in which the deformation action occurs is different by changing the arrangement posture at each installation location. That is, the coupling member 10B coupled to the piezoelectric element 2B has high rigidity in the Y direction, which is the expansion / contraction direction of the piezoelectric element 2B, and is orthogonal to the Y direction in the X and Z directions.
In the direction, it has a low rigidity that is easily deformed. The coupling member 10C coupled to the piezoelectric element 2C is the piezoelectric element 2C.
It has high rigidity in the Z direction, which is the direction of expansion and contraction, and low rigidity in which it is easily deformed in the X and Y directions orthogonal to the Z direction. Each of the coupling members 10A to 10C is
It is placed at a corresponding installation location so as to produce the above deformation characteristics.

Although the connecting members 10A to 10C are integrally formed in the illustrated example, they are parallel plate structure portions 12a and 12c.
It is also possible to form b as a separate member and connect the intermediate rigid body portions.

In the structure in which the support member 8 supporting the probe 3 is supported by the piezoelectric elements 2A to 2C, the coupling member 10 is used.
Since A to 10C are provided so as to be supported, the following action occurs in the operation of the fine movement mechanism. For example, it is assumed that the piezoelectric element 2C performs an extension operation as shown in FIGS. The piezoelectric element 2C operates to extend in the Z direction. At this time, since the coupling member 10C has a high rigidity in the Z direction, the force due to the extension of the piezoelectric element 2C is accurately transmitted to the support member 8 and the probe 3, and the probe 3 corresponds to the extension of the piezoelectric element 2C. It moves exactly in the Z direction. On the other hand, the displacement of the probe 3 in each of the X and Y directions hardly occurs because the deforming action described above occurs in the coupling members 10A and 10B. That is, as shown in FIG. 3, when the piezoelectric element 2C extends in the Z direction, the coupling member 10B coupled to the piezoelectric element 2B is parallel-deformed in the Z direction by the parallel plate structure portion above the coupling member 10B, and each of X and Y. Almost no displacement occurs in the direction. The same action occurs with the coupling member 10A coupled to the piezoelectric element 2A. Therefore, the tip of the probe 3 generates a desired displacement only in the Z direction by the extension operation of the piezoelectric element 2C, and does not generate a displacement in the X and Y directions. In this way, the probe 3 can be precisely moved in the axial direction thereof, that is, in the height direction when viewed from the unevenness of the sample measurement surface.

Regarding the other coupling members 10A and 10B,
When the corresponding piezoelectric elements 2A and 2B extend, they function as members having high rigidity in the extension direction, and easily deform when external force is applied in the other two directions orthogonal to the extension direction. Functions as a member.

In the above-mentioned embodiment, the fine movement mechanism using the piezoelectric element as the means for finely moving the probe 3 in the axial direction or the means for scanning the probe 3 has been described, but other actuators having the same operation function are provided. The configuration of the present invention can be applied to the fine movement mechanism. Further, as an example of the connecting member, it is desirable to use a two-stage parallel plate structure, but other mechanical elements having similar functions can also be used.

Next, another embodiment of the present invention will be described with reference to FIGS. In this embodiment, in the configuration of the above-described embodiment, strain gauges are provided at predetermined positions of the coupling members 10A to 10C, and when deformation occurs in the coupling member due to expansion and contraction of the corresponding piezoelectric element, the deformation is prevented. It is configured to utilize the piezoelectric element to measure the amount of movement.

5 and 6, the coupling member 10B is shown as an example. The coupling member 10B has the parallel plate structure portions 12a and 12b as described above. The lower surface of the coupling member 10B is fixed to the piezoelectric element 2B, and the upper surface thereof is fixed to the lower surface of the support member 8. Illustration of the piezoelectric element 2B and the support member 8 is omitted for convenience of description. Strain gauges 20z1, 2 are provided on the outer surface of the front side flat plate 14 of the parallel flat plate structure portion 12b in FIG.
0z2 is attached, and strain gauges 20z3 and 20z4 are attached to the outer surface of the opposite flat plate 14. This mounting relationship is apparent from FIG. Parallel plate structure 12b
By accurately detecting the displacement amount in the Z direction when a force in the Z direction is generated and the parallel plate structure portion 12b of the coupling member 10B is deformed by using the four strain gauges 20z1 to 20z4 arranged in the. You can

In order to detect the displacement amount of deformation using the four strain gauges 20z1 to 20z4, the detection circuit shown in FIG. 7 is used. In this detection circuit, four strain gauges 20z1-2
A bridge circuit is formed by 0z4, a required voltage is applied to the bridge circuit by a power source 21, and an output voltage is taken out from an output terminal of the bridge circuit via an amplifier 22. According to this detection circuit, for example, when the coupling member 10B is deformed in the state as shown in FIG.
z1 and 20z3 will expand, and strain gauges 20z2 and 20z4 will contract. As a result, in the bridge circuit shown in FIG. 7, the lance is broken and a voltage proportional to the amount of displacement can be taken out from the output terminal with high sensitivity. Thus the probe 3
When the piezoelectric element 2C for adjusting the distance between the sample and the sample surface is extended, a small amount of movement of the probe 3 in the Z direction is applied to the strain gauges 20z1 to 2z arranged in the parallel plate structure portion 12b of the coupling member 2B.
It is possible to measure accurately using 0z4.

With the same configuration, four strain gauges are also arranged in the parallel plate structure portion 12a of the coupling member 2B to form a bridge circuit, and when a force in the X direction is generated and deformation occurs,
It is configured to detect the amount of displacement due to this deformation. 5 and 6, two of the four strain gauges 20x1 and 20x2 are shown.

Further, with respect to the other coupling members 10A and 10C, a strain gauge and a detection circuit for detecting the displacement amount constituted by the strain gauges are provided in the same configuration as that of the coupling member 10B.

By utilizing the detection circuit shown in FIG. 7, the control system of the piezoelectric element 2 shown in FIG. 8 can be constructed. The piezoelectric element 2 is any of the piezoelectric elements 2A to 2C described above. Reference numeral 23 denotes the detection circuit shown in FIG. 7, which corresponds to the piezoelectric element 2. Detection circuit 23
As described above, includes the bridge circuit 24, the power supply 21, and the amplifier 22. The output of the detection circuit 23, that is, the detected signal is supplied to the controller 25.

The controller 25 has a function of controlling the expansion / contraction operation of the piezoelectric element 2, and sends a necessary control signal to the piezoelectric element drive power supply 26. The piezoelectric element driving power supply 26 outputs a voltage corresponding to the input control signal, applies the voltage to the piezoelectric element 2, and expands / contracts the piezoelectric element 2 to a required length.

In the above control system, when the piezoelectric element 2 expands and contracts based on the control signal, the displacement amount due to the expansion and contraction is detected by the detection circuit 23 and input to the controller 25. The controller 25 compares the displacement amount detected by the detection circuit 23 with the initially set control target amount, and further outputs a control signal so that the difference becomes 0.
Output to 6. Thus, in the control system, feedback control is performed, and control for accurately moving the probe 3 to the target position is performed.

Since the above fine control mechanism is provided in the fine movement mechanism of the probe,
It is possible to eliminate the influence of the hysteresis characteristic and non-linearity which the piezoelectric element 2 originally has in the voltage / expansion / contraction amount characteristic, and it is possible to improve the accuracy of the displacement amount generated in the fine movement mechanism.

[0047]

As is apparent from the above description, the present invention has the following effects. In the fine movement mechanism of the probe, between the probe support member and the three piezoelectric elements whose operation directions are orthogonal to each other, each piezoelectric element has a high rigidity in the operation direction and the other two piezoelectric elements orthogonal to the operation direction. Since a coupling member with low rigidity is provided in the direction of movement of the element, the probe can be moved only in the necessary direction when the piezoelectric element is expanded and contracted, and it can be displaced in other directions. Can be prevented from occurring. As a result, an error does not occur in the movement of the probe by each piezoelectric element of the fine movement mechanism, and a highly accurate STM image that does not include distortion can be obtained.

In the structure in which the coupling member is provided in the fine movement mechanism of the probe, the displacement detecting means is provided by utilizing the deformed portion of the coupling member. Therefore, a feedback control system is used in the control system for controlling the operation of the piezoelectric element. This can be realized, and the amount of movement of the probe by the piezoelectric element can be accurately controlled.

[Brief description of drawings]

FIG. 1 is a front perspective view of a fine movement mechanism of a scanning tunnel microscope according to the present invention.

FIG. 2 is a side view showing a state before the extension operation of the fine movement mechanism according to the present invention.

FIG. 3 is a side view showing a state after the extension operation of the fine movement mechanism according to the present invention.

FIG. 4 is an enlarged perspective view showing an example of a coupling member.

FIG. 5 is a perspective view showing another embodiment of the coupling member.

FIG. 6 is a side view of a coupling member according to another embodiment.

FIG. 7 is a circuit diagram showing a displacement amount detection circuit using a strain gauge.

FIG. 8 is a configuration diagram showing an example of a feedback control system of a fine movement mechanism according to the present invention.

FIG. 9 is a perspective view of a conventional fine movement mechanism.

FIG. 10 is a side view showing a state before the extension operation of the conventional fine movement mechanism.

FIG. 11 is a side view showing a state after the extension operation of the conventional fine movement mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base member 1a-1c ... One part 2, 2A-2C ... Piezoelectric element 3 ... Probe 4A-4C ... Power line 5 ... Probe attachment part 8 ... Support member 10A-10B ... Coupling member 12a, 12b ... Parallel plate Structure part 13, 14 ... Flat plate 20z1-20z4 ... Strain gauge 23 ... Detection circuit 24 ... Bridge circuit 25 ... Controller

Claims (5)

[Claims] 1. A probe arranged such that its tip faces a measurement surface of a sample, a support member for supporting the probe, and the probe supported by the support member on the measurement surface. Two actuators for scanning along and an actuator for finely moving the probe in the axial direction are provided, and the three actuators are coupled to the support member in a positional relationship in which respective operation directions are orthogonal to each other. In the fine movement mechanism of the scanning tunnel microscope, each of the three actuators has a high rigidity in the operating direction of each actuator at the joint between the supporting member and the other two actuators. A fine movement mechanism of a scanning tunneling microscope characterized in that a coupling member having low rigidity is arranged in the movement direction of the actuator. 2. The fine movement mechanism of the scanning tunneling microscope according to claim 1, wherein the coupling member is deformed in a parallel plate structure having a deformability in a first direction and in a second direction orthogonal to the first direction. A fine movement mechanism of a scanning tunneling microscope, characterized in that the parallel plate structure portion having ease is formed by being overlapped in the driving direction of the corresponding actuator. 3. The fine movement mechanism of the scanning tunneling microscope according to claim 2, wherein the coupling member has a two-stage parallel plate structure. 4. The fine movement mechanism of the scanning tunneling microscope according to claim 1, further comprising a control means for controlling an operation amount of the actuator, and a displacement detection means attached to a portion of the coupling member having low rigidity. A fine movement mechanism of a scanning tunnel microscope, wherein a feedback control system of the actuator is configured by inputting a detection signal relating to a displacement amount output from a displacement detection means to the control means. 5. The fine movement mechanism of the scanning tunneling microscope according to claim 4, wherein the displacement detecting means is a bridge circuit configured by a strain gauge arranged on the deformable surface of the coupling member. Fine movement mechanism of scanning tunneling microscope.