JPH02163601A - Scanning type tunnel microscope - Google Patents

Abstract

PURPOSE:To obtain a concise structure, and also, to improve an S/N ratio and reproducibility at the time of positioning by constituting the microscope so that an objective lens, an STM (scanning type tunnel microscope) detecting element and an I/V amplifier are supported by a moving mechanism. CONSTITUTION:In an arm 9 of a device, an optical microscope 2 and a uniaxial table 20 of one example of a moving mechanism are fixed, and in the table 20, a revolver 3, an STM detecting element 1 and an I/V amplifier 19 are supported. Also, in the revolver 3, an objective lens 4 is attached. Moreover, the table 20 can move in the direction as indicated with an arrow. In such a way, by placing the amplifier 19 in the vicinity of the detecting element 1 and shortening a signal line 11b, an S/N ratio can be improved. Also, since a wiring 11 is brought to only uniaxial movement, a winding mechanism is not required and tension is scarcely applied and the positioning reproducibility of the table 20 can be improved. Moreover, it is unnecessary that the revolver 3 controls a rotation angle, and the automization can also be executed easily.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a scanning tunneling microscope (STM device) that aligns the measurement position of a sample with other measuring means and performs measurement using a scanning tunneling microscope. More specifically, the present invention relates to an STM device that combines an optical observation means and an STM detection section.

[Conventional technology]

The STM device has a resolution on the atomic level,
In recent years, it has begun to be used to observe fine surface shapes in the micrometer range. Although STM devices have high resolution, they are characterized by a narrow maximum observation area of about 101!1 m. For this reason, it is very difficult to align the observation area with the desired location (for example, the edge) of the sample in the STM apparatus.

Precision sample moving table STM equipment (for example, 1930
[
In the case of "Development of the Sample Moving Stage Ima JSTM Device"), rough positioning is performed from the diagonal side, and then the sample is moved slightly using a precision moving table to re-manipulate the STM measurement, and positioning is done through trial and error. I didn't get it. For this reason, it has become necessary to align the desired measurement position of the sample using optical observation means and to align the 37M measurement area to this position.

For this reason, it is possible to combine optical sample observation means and STM to align to the desired measurement position37.
As an M device, the one shown in FIG. 5 is known. In this device, an objective lens 4 and an STM detection unit 1 are supported by a revolver 3 of an optical microscope (hereinafter referred to as the top). Perform alignment using the cross cursor. When the revolver 3 is further turned, the STM detection section 1 comes to be directly above the sample 5, and 37M measurement can be performed.

FIG. 6 shows a cross-sectional view of the STM detection section 1. Probe holder 1
04 is fixed to the fine movement element 101, and the probe 102 is removably screwed and fixed to the probe holder 104.

The cover 103 is screwed onto the support stand 105 and constitutes a block. The support stand 105 of this block is attached to the revolver 3 and is attached to the stand 106 with screws 10.
Suppression is fixed at 7. The influence of the deflection of the tip of the probe 1 (12) and the positional deviation of the tip of the probe due to individual differences can be determined by determining where the STM image is in the tip wound and how much it deviates from the cross cursor, and calculating the amount by that amount. This can be removed by moving the sample 5 on the X, Y table 7.8 and correcting it just before starting the 37M measurement.

[Problem to be solved by the invention]

As mentioned above, in the conventional apparatus, the revolver 3 is equipped with an objective lens 4. An STM detection section 1 is supported. As shown in FIG. 6, the STM detection unit 1 requires a wiring 1)a for driving the fine movement element 101 and a signal line 1)b from the probe 102. By the way, the ST attached to revolver 3
Connect the wiring 1) from the M detection unit 1 to the arm 9 from inside the revolver 3.
．． If it is taken out through the inside of the first order 2, etc., there will be problems such as wiring or blocking the field of view of the light microscope when the revolver 3 rotates. Therefore, these wiring lines 1) are drawn out from one hole 10 of the revolver 3, as shown in FIG. When you turn the revolver 3, the position of the draw-out hole 10 also changes, so the position &! 1) The length also changes. For this reason, a machine v1)2 is required to wind up the wiring 1) and constantly apply tension.

Figure 7 shows the schematic structure. Figure 7 fat is a plan view, +a
+ is a cross-sectional view. The pulley 13 is fixed to the outer ring of the bearing 4. The inner ring of the bearing 14 is fixed with a piece 15, and a John spring 16 is attached inside the piece 15.
One end is fixed. The other end is fixed to the plate 17 on the pulley 13 with a spring presser, giving the pulley 13 a force for winding up the wiring 1).

The wiring 1) is wound around the pulley 13 and pulled out from the center of the plate 17, that is, the rotation center of the pulley 13, so that the length of the wiring 1) does not change thereafter. With this mechanism 12, even if the revolver 3 is rotated, the wiring 1)
can be kept in tension at all times. Note that if tension is not applied, the wiring 1) will hang down and become part of the sample 5, it will block the focal side of the objective lens 4, it will look bad, it will hit the probe 102 at the tip of the STM detector 1, and the probe 102 will bend. Problems such as 1) may be caught. However, applying tension may adversely affect the positioning accuracy of the revolver 3. ■In this configuration, probe 1
The signal line 1)b from 02 is connected to I via the winding mechanism 12.
/■ Since it is connected to the amplifier 19, the length of the signal line 1)b becomes long. Therefore, the impedance becomes high and the S/
N decreases. (2) If the revolver 3 is allowed to rotate freely, the arrangement 'a] 1 will be wound up by the objective lens 4, etc., causing wire breakage, etc. Therefore, it is necessary to provide a rotation stopper to prevent the revolver 3 from rotating more than once. ■There are problems such as difficulty in automation due to the tension applied to the revolver 3 and the regulation of the rotation angle of the revolver 3.

[Means to solve the problem]

In order to solve the above-mentioned problems, an STM was adopted in which an objective lens, an STM detection section, and an I/V amplifier were supported by a moving mechanism.

[Effect]

According to the above configuration, the wiring of the STM detection section can be installed without affecting the measurement, and by moving the - axis table, it is possible to switch between the forward measurement and the 37M measurement. The positional deviation between the leading measurement and the STM measurement can be corrected by using the method described in the conventional technique as is. In this case, when the −-axis table is moved to the forward position or STM position, the position repeatability becomes a correction error, but positioning using clicks, etc. can achieve accuracy equal to or higher than that of a revolver. .

〔Example〕

FIG. 1 shows an embodiment according to the present invention. In the am 9 of the device, the head 2 and a single-axis table 20, which is an example of a moving mechanism, are fixed.
The -axis table 20 supports a revolver 3, an STM detector 1, and an l/V amplifier 19. That is, a mounting base 25 is installed on the -axis table 20, and the STM detection unit 1 is fixed to the mounting base 25 with screws 107. The wiring inside the STM detection section and its mounting are removably electrically connected to the base using terminal pins and sockets. An I/V amplifier 19 is supported on a uniaxial table near the mount 25, and the mount 25 and the I/V amplifier are also electrically connected. An objective lens 4 is attached to the revolver 3. - the axis table 20 is movable in the direction of the arrow and is positioned at two points; one is the first
The state shown in the figure is a state in which the optical axis 21 of the leading part 2 and the central axis 22 of the objective lens 4 at the measurement position are aligned, and the other point is the optical axis 21 and the central axis 23 of the STM detector 1.
is the matching position. The figure shows one example of positioning means. - The shaft table 20 is supported by the arm 9 so as to be slidable in the uniaxial direction by the dovetail 9a and the dovetail groove 20a.

A positioning groove 9b is formed in the arm 9, and click balls 24 are biased in two directions by springs at two locations on the -axis table side, and the click balls are pressed against the grooves for positioning. When performing STM measurement in FIG. 1, a predetermined location on the sample 5 is observed with the objective lens 4, and its position is aligned with the cross cursor in the previous order. Rotate the revolver 3 and move it to the 37M position using the -axis table 20 while setting it in the position where the objective lens is not attached (the position of the hole 10). In this state, X table 7, Y table 8
Then, the position of the deviation amount between the center axis 22 of the objective lens 4 and the center axis 23 of the STM detection unit 1, which has been obtained in advance, is corrected, and an automatic approach is performed until the X table 6 detects the tunnel current. Position correction is as described in the prior art.
According to this configuration, the I/V amplifier J9 can be placed every other side of the srMt* output section 1, the signal line 1)b can be shortened, and the S/N ratio can be improved.

In addition, since the wiring (1) only moves on one axis, there is no need for a winding mechanism and almost no tension is applied.
0 positioning reproducibility can also be improved. Furthermore, the revolver 3 does not need to regulate its rotation angle, and can be easily automated.

FIG. 2 is a side view of a second embodiment of the present invention, and is a uniaxial table 2.
This is a configuration in which the objective lens 4 is directly supported at 0. Figure 3 is a side view of the third embodiment, showing two STM detection units (la,
1b) - This is a configuration mounted on the shaft table 20'. FIG. 4 is a side view of the fourth embodiment, showing a configuration example in which a revolver 3 for an objective lens and a revolver 3a for an STM detection section are mounted on a uniaxial table 20. In this way, if the revolver can be equipped with a large number of STM detectors, the atomic ST
An M detection section and a shape measurement STM detection section can be provided. Furthermore, by providing a plurality of STM detection sections of the same type, if the probe 102 becomes abnormal due to, for example, being hit, it can be easily replaced. In FIG. 4, the wiring 1) is drawn out from the revolver 3a through the center of the rotating shaft of the revolver 3a.

The reason why the wiring 1) cannot be drawn out through the rotating shaft of the revolver in FIG. 1, which shows a conventional example, is that it blocks the optical axis.

〔Effect of the invention〕

As described above, according to this configuration, the STM detection section and the
By shortening the signal line between /V amplifiers, the S/N ratio can be improved. No wiring winding mechanism is required, resulting in a clean structure. No tension is applied to the wiring, making it easier to reproduce positioning. It is very effective, as it improves performance and can be easily automated.

[Brief explanation of the drawing]

Fig. 1 is a side view of the first embodiment of the present invention, Fig. 2 is a side view of the second embodiment, Fig. 3 is a side view of the third embodiment, and Fig. 4 is a side view of the fourth embodiment. , FIG. 5 is a side view showing a conventional example, FIG. 6 is a sectional view of the STM detection section, and FIG. 7 (al is a plan view of the winding mechanism, and FIG. 7 Fbl is a sectional view of the winding mechanism. 1... STM detection unit 3... Nosepiece 4... Objective lens 5... Sample 1)... Wiring 12... T/V amplifier 20... -axis table (moving mechanism) Above

Claims (4)

[Claims] (1) A scanning tunneling microscope (STM) device that performs scanning tunneling microscopy (STM) measurement by aligning the measurement position of a sample with optical observation means, characterized in that the objective lens and the STM detection unit are supported by a moving mechanism that can position them. type tunneling microscope. (2) The scanning tunneling microscope according to claim 1, characterized in that a revolver portion capable of fixing a plurality of objective lenses is supported by a moving mechanism. (3) The scanning tunneling microscope according to claim 1 or 2, wherein a plurality of STM detection sections are supported by a moving mechanism. (4) The scanning tunneling microscope according to any one of claims 1 to 3, wherein a plurality of STM detection units are rotatably and positionably supported by the moving mechanism via a revolver.