JPH01213947A - Solid surface evaluating device - Google Patents

Abstract

PURPOSE:To allow the detailed analysis of solid surface structure by forming the device from a scanning type tunnel microscope and an electric field ion microscope, and stripping the adsorbed substance, etc., on the specimen surface by electric field evaporation phenomenon in the mentioned electric field ion microscope when the surface structure is to be analyzed by the scanning type tunnel microscope. CONSTITUTION:A solid surface evaluating device according to existing invention includes No.1 power supply 7 to impress voltage between a needle-shaped specimen 2 and a scanning stylus 3, a current measuring instrument 8 to measure the tunnel current flowing between the specimen 2 and scanning stylus 3, a height measuring instrument 11 to measure variation in the height of the scanning stylus 3, No.2 power supply 13 to impress voltage on the specimen 2, and an observing means 15 to observe the image of the ion ionized right over the surface atoms of the specimen 2. An electric field ion microscope and a scanning type tunnel microscope are arranged so that the images on them can be observed and compared in a single device, and in observing the scanning type tunnel microscope image, adsorbed substance, etc., on the specimen surface is stripped through utilization of the electric field evaporation phenomenon which occurs at the time of observing the electric field ion microscopic image. This enables precise evaluation of the solid surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid surface evaluation device for determining the structure of a solid surface.

[Conventional technology]

Conventionally, field ion microscopes or scanning tunneling microscopes have been used as solid surface evaluation devices.

A field ion microscope applies a voltage to a (cooled) needle-shaped sample, ionizing the imaging gas directly above the atoms on the sample surface.
By projecting these ions onto a fluorescent plate, it is possible to observe an image of atoms on the sample surface.

In addition, in a scanning tunneling microscope, a voltage is applied between the sample and the scanning needle, and the height of the scanning needle is changed to keep the tunnel current flowing between the sample and the scanning needle constant. This device is capable of observing the structure of a sample surface with a resolution below the atomic size by scanning the scanning needle and measuring the scanning distance and change in height of the scanning needle.

[Problem to be solved by the invention]

Field ion microscopes cannot be said to have sufficient resolution to observe individual atoms under all observation conditions.

Although scanning tunneling microscopes are said to pose no problems in terms of this decomposition network, there is no established method for holding the clean surface of a sample in a pile for single-surface observation.

[Means to solve the problem]

The solid surface sensitive device of the present invention includes a first power source that applies a voltage between a needle-shaped sample and a scanning needle, and a current measuring device that measures a tunnel current flowing between the sample and the scanning needle. a vertical movement means for changing the height of the scanning needle according to the surface shape of the sample so as to keep the tunneling current constant; a height measuring device for measuring changes in the height of the scanning needle; and a height measuring device for measuring changes in the height of the scanning needle. a distance measuring device that measures the scanning distance of the scanning needle; a second power source that applies voltage to the sample; a cooler that cools the sample; an observation means for observing an ion image of ions ionized by a vacuum pump for evacuating the inside of a housing housing the scanning needle, the sample, and the observation means; and a gas source for introducing the gas.

[Effect]

In the present invention, the structure of a solid surface can be evaluated more strictly than conventional methods by evaluating the structure of a solid surface using two devices, a scanning tunneling microscope and a field ion microscope, which operate on different principles.

We also discuss maintaining a clean surface, which is an issue when evaluating surface structures using scanning tunneling microscopy.

By field evaporation phenomenon in field ion microscopy.

This problem can be solved by stripping off the adsorbed substances on the surface of the sample.

〔Example〕

Next, one embodiment of the present invention will be explained with reference to the drawings.

Figure g1 is a 10° view showing the configuration of an embodiment of the present invention. In Fig. 1, l is a housing, 2 is a needle-shaped sample, 3 is a scanning needle, and 4 is an actuator # for scanning the scanning needle.
5 is a control device for the actuator 4, 6 is a measuring device for the scanning distance of the scanning needle 3, 7 is a power source that applies voltage between the sample 2 and the scanning needle 3, and 8 is a voltage flowing between the sample 2 and the scanning needle 3. 9 is an actuator for changing the height of the scanning needle according to the shape of the sample 2 so as to keep the tunnel current constant; 10 is a control device for the actuator 9; 11 is a scanning device; a measuring device for the change in the height of the needle 3;
1211 A coarse movement device for moving the scanning needle 3 and the actuator 9, 13 a power source for applying voltage to the sample 2 to observe a field ion microscope image, 14 a cooler for cooling the sample 2, 15 an ion image A fluorescent plate for observing 1
Reference numeral 6 denotes a vacuum pump for evacuating the interior of the housing l, and 17 denotes a gas source for introducing gas into the housing l for ion image observation.

In order to observe the field ion microscope characteristics of the sample 2, the scanning needle 3 and the cutter 4.9 are first moved from above the sample 2 using the coarse movement device 12.

The inside of the casing 1 is evacuated by the vacuum pump 16, the sample 2 is cooled by the cooler 14, and gas is introduced into the casing 1 from the gas source 17.
When a voltage is applied to the sample 2 using the power supply 13, the gas introduced into the housing 1 is ionized directly above the atoms on the surface of the sample 20, and these ions are projected toward the fluorescent plate 15).
One surface atomic image is enlarged and projected onto the fluorescent plate 15.

In addition, when the voltage of the power supply 13 is increased, the atoms constituting the sample 2 are ionized on the sample surface and are evaporated from above the sample 2, which is a field evaporation phenomenon, which removes adsorbed substances on the surface of the sample 20. and a clean surface can be obtained. vacuum pump 1
By maintaining a high degree of vacuum inside the casing 1 in step 6, the surface of the clean sample 2 obtained by field evaporation can be kept clean until the surface of the sample 2 is observed using a scanning tunneling microscope. can be retained.

Next, in order to observe the scanning tunneling microscope image of the sample 2, first the coarse movement device 112 moves the scanning needle 3 and the actuator 4.9.
Move it onto sample 2. A voltage is applied between the scanning needle 3 and the sample 20 by the power supply 7, and the height of the scanning needle 3 is changed by the actuator 9 so as to keep the tunnel current flowing between the scanning needle 3 and the sample 2 constant. ), the scanning needle 3 is scanned, the scanning distance is measured by the measuring device 11, and the height of the scanning needle 3 is measured by the measuring device 6). You can observe the image.

〔Effect of the invention〕

As described above, according to the present invention, field ion microscopic development and scanning tunneling microscopic images can be observed in one device.
By utilizing the field evaporation phenomenon that occurs during field ion microscopy image observation, it is possible to compare the Since the problem can be solved, the solid surface can be evaluated accurately.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In Fig. 1, 1 is a housing and 2 is a needle-shaped sample. 3 is a scanning needle, 4 is an actuator for scanning the scanning needle 3, and 5 is an actuator 40 control device. 6Fi measuring device for the scanning distance of the scanning needle 3; 7 is a power source that applies voltage between the sample 2 and the scanning needle 3; 8 is a device for measuring the scanning distance of the sample 2 and the scanning needle 3.
9 is a measuring device for measuring the tunnel current flowing between the scanning needle 3; 7 is a cutter 9 for changing the height of the scanning needle 3;
11 is a device for controlling the actuator 90, and a device for measuring changes in the height of the scanning needle 3. 12 is a coarse movement device for moving the scanning needle 3 and cutieators 4 and 9; 13 is a power source for applying voltage to the sample 2; 14 is a cooler for cooling the sample 2; and 15 is a firefly for observing ion images. A light plate, 16 is an X air pump, and 17 is a gas source. Agent Patent Attorney Oto Uchihara

Claims (1)

[Claims] a first power supply that applies a voltage between the needle-shaped sample and the scanning needle; a current measuring device that measures a tunnel current flowing between the sample and the scanning needle; A vertical movement means for changing the height of the scanning needle according to the surface shape of the sample, a height measuring device for measuring changes in the height of the scanning needle, a scanning means for scanning the scanning needle, and the scanning needle. a distance measuring device for measuring the scanning distance of the sample, a second power source for applying voltage to the sample, a cooler for cooling the sample, and observing an ion image of ions ionized directly above the surface atoms of the sample. a vacuum pump for evacuating the inside of a housing housing the scanning needle, the sample, and the observation means; and a gas source for introducing gas into the housing for ion image observation. A solid surface evaluation device comprising: