JP3229913B2 - Tip moving mechanism of scanning tunneling microscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe moving mechanism in which a scanning tunnel microscope (hereinafter, referred to as STM) probe has an improved approach to a sample.

[0002]

2. Description of the Related Art A conventional STM probe approach will be described with reference to FIGS. In FIG. 2, a probe holder 3 to which a probe 2 is attached is fixed to a PZT 4, and the PZT 4 is fixed to a base 5 using a screw shaft or the like. A motor drive mechanism (not shown) is provided on the base 5 so that the base 5 can move in the direction of arrow A in the figure and approach the sample. A bias voltage is applied between the probe 2 and the sample. In this state, the probe 2 approaches the sample 1 until a tunnel current is detected by the motor driving mechanism.
When the tunnel current is detected, the motor stops, and instead, the scanning drive of the probe 2 by the PZT 4 is controlled. P
Since the moving range of the ZT 4 is several hundreds of nm, the approach of the probe 2 to the sample 1 by the motor drive is not sufficient if the operation accuracy (for example, vibration) is not sufficient because the surface of the sample 1 has irregularities. The needle 2 hits the sample.

[0003] Such a conventional probe moving mechanism will be described in detail with reference to FIG. FIG. 3A is a side view, and FIG.
(B) is a cross-sectional view. The probe holder 3 holding the probe 2 is screwed to the PZT 4, and the PZT 4 is screwed to the holder 6. The holder 6 is movable in the direction of arrow A by a motor drive mechanism (not shown).
Are provided on both sides at the rear end thereof, are constantly pulled away from the sample by two springs 10 attached to the base 8, and are coupled with the motor drive mechanism in the direction of arrow A of the holder 6, ie, in the approach direction, the anti-approach direction. Is balanced. When the probe 2 approaches the sample direction, the holder 6 rolls on two rollers 12, both ends of which are rotatably supported by bearings 13 on the base 8. The upper surface of the holder 6 is in contact with the two rollers 11, 11 attached to the roller holder 7 supported by the support 9, and the upper surface also rolls.
At this time, the play in the direction of arrow B (lateral direction) is restricted by the cylindrical portion of the holder 6 and the tapered surfaces at both ends of the roller 12, and the play in the direction of arrow C (vertical direction) is held by the roller holder 7 and the support 9. Is regulated by the two rollers 7.

[0004]

However, in the method of rolling on a roller as shown in FIG. 3, the bearing of the roller may act as a vibration source, causing the probe to vibrate and hit the sample surface. Since the dimensional accuracy of the contact portion between the cylindrical portion and the tapered surface of the roller is not sufficient, and the backlash in the direction of arrow B is large, the probe hits the sample surface. Also,
Rolling by rollers does not move smoothly, requires a mechanism and space for bearings and rollers, and increases the number of parts. The present invention is to solve the above problems, while preventing the probe from hitting the sample due to vibration at the time of approach, smoothing the movement,
It is another object of the present invention to provide a probe moving mechanism of a scanning tunneling microscope capable of reducing the number of parts and reducing cost, size, and weight.

[0005]

SUMMARY OF THE INVENTION The present invention provides a scanning drive mechanism for scanning and driving a probe, and a moving mechanism for moving a holder on which the scanning drive mechanism is mounted on a base to move the probe toward and away from the sample. In the probe moving mechanism of the scanning tunnel microscope equipped with the above, a triangular groove parallel to the holder axis direction is formed on the lower surface of the holder, and the triangular groove is engaged with a rail provided on the base to slide the holder on the base. The holder is moved, and the lateral movement of the holder is regulated by engagement of the triangular groove with the rail. The present invention also provides a triangular groove and a planar groove formed on a lower surface of a holder, the triangular groove being parallel to the holder axial direction, and each groove being engaged with a rail provided on the base to slide the holder on the base. Characterized in that the horizontal movement of the holder is restricted by the engagement between the holder and the rail. Further, the present invention is characterized in that the rail has a half-moon cross section.

[0006]

According to the present invention, in the STM apparatus, the approach operation of the probe to the sample is changed from rolling movement to sliding movement, so that the vibration is greatly reduced, and the probe is prevented from hitting the sample. By eliminating the need for a mechanism or space for holding the rollers and rollers, it is possible to achieve cost reduction, downsizing, and weight reduction.

[0007]

An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, the same reference numerals as those in FIG. 2 have the same contents, and a detailed description thereof will be omitted. The probe 2 is held by a probe holder 3, and the probe holder 3 is attached to a PZT 4,
Are fixed to the holder 6, respectively. The holder 6 can be moved in the direction of arrow A by a motor drive mechanism (not shown), and the holder 6 is constantly pulled in the direction away from the sample by the spring 10, and is balanced in the approach direction and the anti-approach direction together with the movement by the motor drive mechanism. Is the same as in the case of FIG.

In the present invention, a triangular groove 6 is provided on the lower surface of the holder 6 on which the PZT 4 is mounted in parallel with the holder axial direction.
a, a flat groove 6b is formed, and rails 20 and 21 having a semicircular cross section fixed to the base 8 are engaged with the respective grooves, so that the holder 6 slides on the rail.
The rail has a half-moon shape in order to facilitate processing, but it is needless to say that the rail may have a shape other than the half-moon shape. The reason why only one is a triangular groove and the other is a planar groove is to restrict the lateral movement of the holder with the triangular groove and to facilitate the alignment of the planar groove, but both are triangular grooves. Also, the shape is not necessarily a triangular groove, and may be any shape as long as the shape can restrict lateral movement of the holder. If the rotation of the holder 6 is suppressed by the engagement between the upper roller 11 and the roller holder 7, the sliding movement by the engagement between one groove and the rail is also possible. When approaching the sample with such a moving mechanism, the holder 6 slides on the semi-moon-shaped rails 20 and 21 fixed to the base. In order to reduce friction during sliding, the holder 6 is mirror-polished at the contact surface with the rail, and
21 is subjected to Teflon coating or Kanigen plating containing Teflon particles. In this moving mechanism,
The rattling in the direction of the arrow B is regulated by the triangular groove 6a with which the rail 20 is engaged, and the rattling in the direction of the arrow C is similar to the case of FIG. Is regulated by the two rollers 11 held by the rollers. Since the sliding movement is used in this manner, the movement becomes extremely smooth, and collision of the probe with the sample due to vibration is prevented.

[0009]

As described above, according to the present invention, an approach by rolling on a roller held by a bearing is described.
By changing the approach to sliding movement on a rail with low friction treatment, the movement of the approach becomes smoother, the collision of the probe with the sample due to vibration during the approach is eliminated, and the number of parts is greatly reduced. The cost can be reduced, and the space for holding the bearings and the rollers is not required, so that the size and weight can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a sample moving mechanism of the present invention.

FIG. 2 is a diagram illustrating an approach of a probe to a sample.

FIG. 3 is a diagram illustrating a conventional sample moving mechanism.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... sample, 2 ... probe, 3 ... probe holder, 4 ... PZT, 6
... Holder, 6a Triangular groove, 6b Plane groove, 7 Roller holder, 8 Base, 9 Support, 10 Spring, 11
Rollers, 20, 21, ... rails.

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 13/10-13/24 G12B 21/00-21/24 G01B 7/34 G01R 1/06 H01J 37/28 G01B 21 / 30

Claims (3)

(57) [Claims] 1. A scanning tunnel microscope comprising: a scanning drive mechanism for scanning and driving a probe; and a moving mechanism for moving a holder on which the scanning drive mechanism is mounted on a base and moving the probe toward and away from the sample. In the probe moving mechanism, a triangular groove parallel to the holder axis is formed on the lower surface of the holder.
Scanning characterized in that the triangular groove is engaged with a rail provided on the base to move the holder on the base, and the horizontal movement of the holder is regulated by engagement of the triangular groove with the rail. Tip moving mechanism of tunnel microscope. A scanning drive mechanism for scanning and driving the probe;
Move the holder with the inspection drive mechanism on the base
And a moving mechanism to move the probe close to and away from the sample.
In the probe moving mechanism of the scanning tunneling microscope, a triangular groove and a plane groove parallel to the holder axis direction are formed on the lower surface of the holder.
Each groove with a rail provided on the base.
Slide the rudder on the base,
Engagement restricts lateral movement of holder
A probe moving mechanism for a scanning tunnel microscope. 3. A rail having a half-moon shape in cross section.
The probe moving mechanism according to claim 1 or 2, wherein