JPH01223783A - Fine movement device - Google Patents

Abstract

PURPOSE:To reduce interference in a Z-axis due to in-plane driving without increasing wiring and an in-plane driving power source in a device by a method wherein the poling direction of electrodes facing each other among four or two split electrodes for in-plane scanning is reversed and push-pull operation is performed by applying the same signal. CONSTITUTION:After a cylinder is made of piezoelectric material, an electrode is attached to the outer wall and an inner electrode G is attached to the inner wall. The voltage is applied across the inner electrode G and outer electrode with the temperature of the cylinder made of a piezoelectric material raised to the Curie point, and processing (poling) for aligning the direction of piezoelectric particles is carried out. In this poling, the poling directions of facing electrodes are changed by reversing the direction for applying voltage between X and X' and between Y and Y', with respect to the four split electrodes X, Y, X' and Y'. By applying X-axis driving voltage both to X and X', and applying Y-axis driving voltage both to Y and Y', push-pull driving can be carried out on this fine movement device. In other words, when an equal voltage is applied to X and X', the X' electrode part shrinks if the X electrode part extends, so that the respective electrodes extend and shrink in a reverse direction to each other. This prevents a probe 1 from moving vertically even though in-plane driving is carried out so that interference in the direction of the Z-axis (DELTA=0) can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fine movement element using a piezoelectric element, and more particularly to a cylindrical fine movement element used in a scanning tunneling microscope (hereinafter referred to as STM).

[Summary of the invention]

The present invention is a cylindrical piezoelectric element that performs fine movement by performing circular arc motion by expanding and contracting a pattern portion.The present invention relates to a fine movement element that performs push-pull drive by simultaneously expanding and contracting in opposite directions using two electrodes. A fine movement element characterized by performing push-pull operation with the same drive signal by reversing the direction.

[Conventional technology]

Conventionally, a fine movement element made of a cylindrical piezoelectric element shown in FIG. 2(a) and FIG. On the outside is a patterned outer electrode Z.

It consists of five electrodes: X, There is.

[Problem that the invention seeks to solve]

In a piezoelectric element, a voltage of opposite polarity to the poling direction (
When a reverse voltage is applied, the piezoelectric element in the electrode portion expands in a direction perpendicular to the poling direction. In the conventional fine movement element as described above, for example, when a reverse voltage is applied to the inner chamber PiAG and the outer electrode X, as shown in FIG. ΔX, Z in the direction
ΔZ displacement in the direction.

In STM, as shown in FIG. 4, the deep needle 1 and the sample 3 are scanned in the in-plane direction using the X and Y electrodes 5.7 of the fine movement element 4. The distance between the sample 3 and the deep needle 1 is kept constant by expanding and contracting the fine movement element 4 in the Z-axis direction using the electrode Z9 so that the tunnel current flowing by applying a voltage between them becomes constant. The surface roughness of the sample 3 was measured.

However, in the normally used one-sided electrode drive, that is, one X-axis drive electrode and one Y-axis drive electrode are used to scan the deep needle 1 in the in-plane direction with respect to the sample 3 (for example, one X-axis drive electrode and one Y-axis drive electrode are used). In the in-plane drive method (using only the Y and Y electrodes 7), only one drive power source is required for the It appears as a vertical movement of 1. This results in the measurement result presenting a tilted image for a flat sample. Furthermore, since this vertical movement is absorbed by tracking in the Z-axis direction, the actual measurement range in the Z-axis is reduced. These problems become more noticeable when scanning a large area.

In order to solve the above problem, push-pull drive has also been considered. This method is shown in Figure 4, as shown in Figure 6.
), doubling the in-plane scanning dose tAA n p compared to
Axis scanning signal A and Y-axis scanning signal B are sent directly to the X and Y machines.
The X and Y electrodes are input to the ANP via an inverter, and a signal voltage is applied to all the in-plane scanning electrodes. However, in this format, the number of wirings to the fine movement element increases, reducing the degree of freedom in device design, and furthermore, the low noise Amp doubles, leading to problems such as a cost amplifier.

[Means for solving problems]

The present invention solves the above-mentioned problems by reversing the poling direction of one of the opposing electrodes of the in-plane scanning electrode and connecting each electrode with respect to the conventionally used cylindrical PZT. without increasing the number of Anp for in-plane scanning.
In addition, push-pull drive can be performed without increasing the number of wires within the device.

[Effect]

According to the present invention, by applying the same signal to opposing electrodes whose poling directions are reversed, both electrodes expand and contract in opposite phases, so that a push-pull operation can be performed.

〔Example〕

A first embodiment according to the present invention is shown in FIG. 1(a) and FIG. 1+b+. This fine movement element is made by creating a cylinder using a piezoelectric material, and then having an electrode in the shape shown in Figure 1(b) on the outside and a first electrode on the inside.
The inner electrode G shown in Figure (al) is attached, and then, with the temperature of the cylinder of piezoelectric material raised to the Curie point, a voltage is applied between the inner tiG and each outer electrode to adjust the orientation of the piezoelectric particles (poling). However, in the poling process, the voltage direction to be applied was divided into four electrodes X, Y,
Regarding Y, by reversing X and X and Y and Y, the poling direction of each opposing electrode is changed. Push-pull driving can be performed by applying an X-axis drive voltage to the fine movement element in common to X and X, and a Y-axis drive voltage to common to Y and Y. That is, when the same voltage is applied to X and X, when the X electrode portion expands, the X electrode portion contracts, and the respective expansion and contraction directions can be made to move in opposite directions. For this reason, the seventh
As shown in the figure, even if in-plane driving is performed, there is no vertical movement of the probe l, and interference in the two-axis directions can be suppressed (Δ2=0>).

In this case, compared to FIG. 5 which shows a conventional drive example, both electrodes are driven, so even if the same voltage value is applied,
The amount of movement ΔX in the Y) direction is doubled to 2ΔX.

〔Effect of the invention〕

As described above, according to the present invention, by reversing the polling direction of the opposing electrodes of the 4-part electrode for in-plane scanning or the 2-part electrode and applying the same signal to perform the push-pull operation, the wiring inside the device can be adjusted. , it is possible to reduce interference with the Z-axis due to in-plane driving without increasing the power supply for in-plane driving, and the scanning area can also be increased, which is very useful industrially.

[Brief explanation of the drawing]

Figure 1 ta+ is a cross-sectional view of cylindrical PZT showing the present invention.
Figures (bl is the outer electrode development/connection diagram of the present invention, Figure 2 fa
1 is a cross-sectional view of a conventional cylindrical PZT, FIG. 2 tbl is an outer electrode development/connection diagram, FIG. 3 is an operation diagram explaining the operation of the conventional cylindrical PZT, and FIG. 4 is a conceptual diagram explaining STM. Fifth
The figure is an explanatory diagram showing the problems of the conventional method, and Figure 6 is the conventional PZT.
FIG. 7 is an explanatory diagram showing the push-pull driving method of the present invention. l...Deep needle 2...Cylindrical PZT X, Y, Z...Symbol indicating the scanning direction of electric scratching■,
○・・・A symbol indicating the polling direction or more Applicant: Seiko Electronics Co., Ltd.

Claims (1)

[Claims] A fine movement element made of a cylindrical piezoelectric element, characterized in that it performs push-pull drive by partially reversing the poling direction.