JPH08285519A - Observing method of sample surface and probe used therefor - Google Patents

Abstract

PURPOSE: To obtain a probe for observation of a sample surface which can be manufactured inexpensively by a simple method and, moreover, which scarcely contains impurity and has high resolution and also a method which makes it unnecessary to control the vertical motion of the fore end of the probe and enables direct observation of the sample surface only by making the probe scan in the horizontal direction in a state wherein the fore end thereof is simply brought into contact with the sample surface. CONSTITUTION: A method wherein a probe 1 to the fore end of which an ultrafine particle 1a having piezoelectric properties is fitted is made to scan in the horizontal direction in a state wherein it is brought into contact with a sample surface, a voltage or a current generated from the ultrafine particle 1a in accordance with a pressure applied thereto by indentations of the surface of a sample S is detected and the surface of the sample S is observed on the basis of it, is obtained. Besides, the probe for observation of the sample surface which is useful as the probe for this method for observation of the sample surface, STM, AFM, MFM, etc., and is prepared by fitting the ultrafine particle of a diameter 5-100nm, preferably 5-50nm, to the fore end thereof is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of observing a sample surface, and more particularly, to a method for horizontally scanning a sample with a probe having piezoelectric ultrafine particles attached to its tip in contact with the sample surface. It relates to a method of directly observing a surface.
Furthermore, the present invention relates to such a sample surface observing method and a probe made of ultrafine particles useful as a probe for a scanning tunneling microscope, an atomic force microscope, a magnetic force microscope and the like.

[0002]

2. Description of the Related Art In the early 1980s, a scanning tunneling microscope (hereinafter abbreviated as STM) was developed as an apparatus capable of observing a solid surface with atomic resolution. ST
M is a microscope for three-dimensionally observing the structure of the sample surface by utilizing a tunnel current of about 5 nA to 10 pA flowing between a probe having a sharp tip and a conductive sample. Later, several new microscopes based on the STM measurement principle were developed. Among them, an atomic force microscope (hereinafter abbreviated as AFM) detects an attractive force or a repulsive force (atomic force) between a probe having a sharp tip and a sample and observes unevenness on the sample surface. However, it has been put into practical use as a microscope that can observe surface structures of a wide variety of materials such as semiconductors, metals, and living bodies including insulators that cannot be measured by STM.
On the other hand, a magnetic force microscope (hereinafter abbreviated as MFM) is for observing the sample surface by detecting a magnetic attractive force or repulsive force generated when the sample and the probe are brought close to each other. It is used for observing recorded information.

In the scanning probe microscope as described above, its resolution is affected by the radius of curvature of the tip of the probe. Hereinafter, the STM will be described as an example. General ST
FIG. 4 shows a schematic configuration of M, and FIG. 5 shows an enlarged view of the STM probe portion. First, a method of observing an image of a sample surface by STM will be described. The distance D between the metal probe 1 and the sample S whose tip is very sharp and sharp is kept at an interval of about 0.5 to 1 nm. When a potential difference V _T of about 1 V is applied between S and the probe 1, a tunnel current I _T flows between them. The tunnel current I _T is the distance D between the sample S and the probe 1.
However, when the distance between the sample S and the probe 1 is reduced by 10%, the tunnel current flows ten times, but when the distance D is constant, a constant tunnel current flows. Therefore, the tunnel current I _T flowing between the sample S and the probe 1 is kept constant, that is, the distance D between the probe 1 and the sample S.
When the sample surface is scanned in the horizontal direction while the probe 1 is moved up and down so as to be constant, the up and down movement of the probe 1 corresponds to the unevenness of the sample surface.

Such a vertical movement signal of the probe 1 is detected by the piezoelectric element 2 and stored in the memory 15, and then the CR of the cathode ray tube 17 is controlled by using the microcomputer 16 or the like.
An image is displayed on the T screen 18. The piezoelectric element 2 incorporated in the scanner 10 is used to control the position of the probe 1, the scanning of the probe 1 in the x and y directions is controlled by the XY scanning circuit 12, and the scanning in the z direction (vertical movement) is a servo. Circuit 13
Is feedback controlled by. The servo circuit 1
3, the tunnel current I _T flowing between the probe 1 and the sample S (metal sample support 11) is the tunnel current amplifier 1
It is amplified by 4 and input.

[0005]

The mechanism of the STM currently generally used is as described above. However, in the method of analyzing the structure of the sample surface using the tunnel current, the tunnel current is kept constant. Since the probe must be moved up and down to keep it,
Very precise and very expensive equipment is required. Further, since the tunnel current I _T is influenced by the work function of the probe, if the probe is contaminated and its work function changes, the tunnel current also changes and the measurement accuracy deteriorates. On the other hand, STM
Is affected by the radius of curvature (thickness) of the tip of the probe, and usually, a radius of curvature of 100 nm or more does not provide sufficient resolution. The relationship between the radius of curvature of the tip of the probe and the resolution also applies to AFM and MFM.

Therefore, in order to improve the resolution of STM or the like, the tip of the probe must be sharpened. Conventionally, machining, electrolytic polishing, or a combination thereof has been used for machining such a probe, but it is difficult to reduce the diameter of the probe tip to 1 μm or less by machining. Therefore, a method is used in which a metal probe such as W, Ag, Au, etc., which is generally less likely to be contaminated, is electrolytically polished in a liquid, and its tip is sharpened. However, even with such a method, the radius of curvature of the tip of the probe that has been manufactured so far is about 100 nm, so that there is a drawback that the resolution is difficult to increase. Further, in the case of the electrolytic polishing method, the probe surface is rarely etched smoothly and is often formed on a rough rough surface. further,
Since the electropolishing is performed in a liquid, impurities remain in the probe and contaminate it. For this reason, the electrolytically polished probe needs to have its surface further etched by ion etching or the like and then heated to perform electrolytic evaporation, which is very difficult and time-consuming.

Therefore, an object of the present invention is to solve the problem of the probe used in the conventional STM, AFM, and MFM as described above, to manufacture it by a simple method at low cost, and to contain almost no impurities. And the tip diameter is 100 nm
Therefore, the object is to provide a probe for observing a sample surface having high resolution. Another object of the present invention is S
Unlike TM, it is not necessary to feedback control the vertical movement of the tip of the probe to keep the distance between the sample surface and the tip of the probe constant. Instead, the tip of the probe is simply brought into contact with the sample surface to scan in the horizontal direction. The object is to provide a method for directly observing the sample surface only by performing the above.

[0008]

In order to achieve the above object, according to the present invention, a probe having ultrafine particles having piezoelectricity attached to the tip is horizontally scanned while being in contact with the sample surface. Provided is a novel sample surface observing method characterized by observing the surface of a sample by detecting a voltage or current generated from the ultrafine particles according to the pressure applied to the tip of the probe due to the unevenness of the sample surface. . Further, according to the present invention, such a sample surface observation method, STM, AFM,
5-100n at the tip of the probe, useful as a probe for MFM, etc.
A probe for observing a sample surface is provided, to which ultrafine particles having a diameter of m, preferably 5 to 50 nm are attached. The ultrafine particles used in the novel sample surface observation method and the AFM probe according to the present invention are required to have piezoelectricity.
The ultrafine particles used for the M probe have conductivity, and MF
The ultrafine particles used for the M probe are required to have magnetism.

Examples of the ultrafine particles having piezoelectricity, conductivity, or magnetism include ultrafine aluminum nitride particles, ultrafine aluminum nitride particles in which a rare earth element is dissolved, ultrafine particles composed of a composite phase of aluminum nitride and rare earth nitride, and nitriding particles. Al-M ¹ -N consisting of a composite phase of aluminum and metal, intermetallic compound or nitride ceramics (where M ¹ is C
Al-M ² -M consisting of a composite phase of (based on at least one metal element selected from the group consisting of r, Fe, Co and Ni) based ultrafine particles, aluminum nitride and metal, intermetallic compound or nitride ceramics ^3- N (However, M ² is C
at least 1 selected from the group consisting of r, Co and Fe
Species metal element, M ³ is Au, Cu, Dy, Er, Ga,
Ge, Gd, Hf, Ho, Lu, Mn, Mo, Nb, N
d, Ni, Pr, Re, Sb, Sc, Si, Sn, T
a, Tb, Ti, Tm, V, W, Y, Zn and at least one metal element selected from the group consisting of Zr)
-Based ultrafine particles, barium titanate ultrafine particles, PbZrO ₃
-PbTiO ₃ solid solution ultrafine particles, can be used titanate ultrafine particles, SiO ₂ ultrafine particles, lithium niobate ultrafine particles, lithium tantalate ultrafine particles, and ZnO ultrafine particles or the like. The shape of the ultrafine particles may be rod-shaped, needle-shaped, whisker-shaped, or spherical.

[0010]

According to the method of observing a sample surface of the present invention, a probe having ultrafine particles having piezoelectricity attached to the tip is horizontally scanned while the probe surface is in contact with the sample surface. As a result, pressure is applied to the ultrafine particles at the tip of the probe due to the unevenness of the sample surface, but since the ultrafine particles have piezoelectricity, a voltage is generated from the ultrafine particles according to the applied pressure. The generated voltage or the current generated by it is detected. Since this change in voltage or current corresponds to the unevenness of the sample surface,
The surface of the sample can be observed. Further, according to another aspect of the present invention, such a sample surface observation method and ST
As a probe for M, AFM, MFM, etc., 5 to 1 at the tip of the probe
A sample surface probe equipped with ultrafine particles having a diameter of 00 nm, preferably 5 to 50 nm is used. By using the extremely fine ultrafine particles as the tip of the probe, the resolution is greatly improved. Further, since such ultrafine particles can be easily produced by a gas phase method such as a so-called gas evaporation method using an arc melting method or the like, they have high purity and are extremely fine, and their size and morphology are It can be controlled depending on the manufacturing conditions. Therefore, unlike the conventional processing of the tip of the probe by electropolishing, there is no risk of impurities being contained in the tip of the probe, and no post-treatment such as ion etching or electrolytic evaporation is required.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the basic configuration of the sample surface observation method of the present invention. First, the ultrafine particles 1a having piezoelectricity as described above are fixed to the tip of the conventional probe 1 made of a conductive material such as metal by an appropriate means such as adhesion. It is desirable to use a conductive paste as the adhesive. When the probe 1 having the ultrafine particles 1a having piezoelectricity attached to the tip thereof is brought into contact with the surface of the sample S at a constant contact pressure, a voltage is generated from the ultrafine particles 1a having piezoelectricity. In this state, when the probe 1 is scanned in the horizontal direction (x and y directions shown in FIG. 5), the pressure applied to the ultrafine particles 1a at the tip of the probe 1 changes due to the unevenness of the sample surface. As a result, the potential generated from the ultrafine particles 1a changes as schematically shown in FIG. Since this change in potential corresponds to the unevenness of the sample surface, the change in this potential or the change in current generated thereby is detected, and the conventional S shown in FIG.
Images can be displayed by the same device as the TM. According to such a sample surface observing method, unlike the conventional STM, there is no scanning (vertical movement) of the probe 1 in the Z direction, and therefore it is not necessary to feedback-control the position of the probe 1 in the Z direction. Therefore, the structure of the device is simplified. The measuring mechanism is the same as the conventional STM measuring mechanism except that the mechanism for feedback controlling the position of the probe 1 in the Z direction is not necessary, and therefore its detailed description is omitted.

The piezoelectric ultrafine particles attached to the tip of the probe 1 are ultrafine particles produced by a gas phase method such as so-called gas evaporation method, for example, Japanese Patent Application No. 5-80325.
Japanese Patent Application No. 5-246063, Japanese Patent Application No. 6-79282
Aluminum nitride ultrafine particles, aluminum nitride ultrafine particles in which a rare earth element is solid-dissolved, ultrafine particles composed of a composite phase of aluminum nitride and rare earth nitride, aluminum nitride and metal, intermetallic compound or nitride ceramics Al-M ¹ -N (where M ¹ represents at least one metal element selected from the group consisting of Cr, Fe, Co and Ni) consisting of a composite phase, ultrafine particles, aluminum nitride and metal, intermetallic Al-M ² -M ³ -N (where M ² is C
at least 1 selected from the group consisting of r, Co and Fe
Species metal element, M ³ is Au, Cu, Dy, Er, Ga,
Ge, Gd, Hf, Ho, Lu, Mn, Mo, Nb, N
d, Ni, Pr, Re, Sb, Sc, Si, Sn, T
a, Tb, Ti, Tm, V, W, Y, Zn and at least one metal element selected from the group consisting of Zr)
Ultrafine particles and the like can be preferably used. The morphology of these ultrafine particles is influenced by the composition of the raw material (mother alloy), the production conditions such as the atmospheric gas at the time of heating and melting, and various morphologies such as rod-like, needle-like, whisker-like or spherical It is made. Such ultrafine particles can be used as the ultrafine particles attached to the tip of the probe of the present invention, because aluminum nitride (AlN) has piezoelectricity. Other piezoelectric materials include barium titanate (BaTiO ₃ ) ultrafine particles and PbZrO ₃ —PbTiO _3.
3 type solid solution (PZT) ultra fine particles, lead titanate (PbTi)
O ₃ ) ultrafine particles, SiO ₂ ultrafine particles, lithium niobate (LiNbO ₃ ) ultrafine particles, lithium tantalate (Li
It is possible to use rod-shaped ultrafine particles such as TaO ₃ ) ultrafine particles and ZnO ultrafine particles (spherical in the case of SiO ₂ ultrafine particles).

Explaining the preparation of the ultrafine particles as described above, first, a binary alloy of 10 to 60 atomic% metallic aluminum and 40 to 90 atomic% rare earth element is used as a melting master alloy, and the above alloy is prepared in a nitrogen atmosphere. When it is heated and melted by arc melting or the like, the nitriding rate of the produced ultrafine particles is rapidly increased, and aluminum nitride ultrafine particles having a shape anisotropic structure with an aspect ratio of 1 or more are produced. Further, by appropriately selecting the composition and nitrogen partial pressure of the above binary alloy, substantially no metal aluminum ultrafine particles are contained, and hexagonal columnar or whisker-like shape anisotropic aluminum nitride is used together with a rare earth element nitride. Are produced, and ultrafine particles in which these ultrafine particles are uniformly mixed are produced.

The hexagonal columnar ultrafine particles contain 2 to 2 rare earth elements.
It is aluminum nitride containing about 25 atomic% of solid solution or nitride particles of rare earth elements, and its growth direction is the crystal (hexagonal) C-axis direction of aluminum nitride. On the other hand, the whisker-shaped ultrafine particles are single crystals of aluminum nitride, and it is considered that the growth is remarkably promoted in the C-axis direction of the aluminum nitride crystal and turned into whiskers. Generation of such whisker-shaped ultrafine aluminum nitride particles is observed in rare earth elements other than samarium, europium, and ytterbium.

Also, aluminum 5 to 95 is used as a raw material.
Atomic% and M ¹ element (provided that M ¹ has the same meaning as above) 5 to 95 atomic%, preferably aluminum 25 to 7
An alloy consisting of 5 atomic% and M ¹ element 25 to 75 atomic%,
Or aluminum 5 to 45 atom% and M ² element 5 to 4
An alloy composed of 5 atomic% and 10 to 90 atomic% of M ³ element (provided that M ² and M ³ have the same meanings as described above) is used, and nitrogen gas, nitrogen gas containing hydrogen gas, or nitrogen gas is contained. By heating and melting in an inert gas atmosphere,
Composite ultrafine particles consisting of a composite phase of aluminum nitride and a metal, intermetallic compound or nitride ceramic, and having a structure in which whisker-like or columnar aluminum nitride extends from the ultrafine particles of metal, intermetallic compound or nitride ceramic Ultra-fine particles of nm order containing a large amount of are generated.
Further, depending on the manufacturing conditions, a mixture of ultrafine particles of a metal, an intermetallic compound or a nitride ceramic and ultrafine aluminum nitride particles in the form of whiskers or columns is formed.

For example, when a binary alloy of aluminum and chromium, cobalt or iron is used as the mother alloy, a nitride ceramic (β-Cr ₂ N) and an intermetallic compound (Al-Cr) are used.
System, Al-Co system, Al-Fe system) or metal (Co or α-Fe) ultrafine particles containing a large amount of nitride composite ultrafine particles having a structure in which whisker-like or columnar aluminum nitride is extended. Fine particles are obtained. In addition, Al-
M ² -M ² system (M ² as the -M ² Cr, Co and Fe
Even if a ternary alloy of (2 kinds selected from among) is used, ultrafine particles of a metal (Co or α-Fe), an intermetallic compound or a nitride ceramic (β-Cr ₂ N) depending on the composition of the alloy. It is possible to obtain nitride ultrafine particles containing a large amount of nitride composite ultrafine particles having a structure in which whisker-like or columnar aluminum nitride is extended, and this means that the above-mentioned Al-M ² -M ³
The same applies to system alloys.

As the heating and melting method of the mother alloy, there are an arc melting method, a high frequency heating melting method, a plasma jet heating method,
A high frequency induction heating method (high frequency plasma heating), an electron beam heating method, a laser beam heating method, or the like can be used. Since the aluminum nitride has piezoelectricity, the ultrafine particles as described above can be used as a probe tip of a sample surface observing method by a mechanism as shown in FIG. 1, and can also be used as a probe tip of STM or AFM. Further, in the case of the composite ultrafine particles of the combination of magnetic material (metal) -nonmagnetic material (ceramic), it can be used as the tip of the MFM probe. Hereinafter, some production examples of the above-mentioned ultrafine particles will be shown.

FIG. 3 shows an example of an apparatus 20 for producing composite ultrafine particles by arc melting, and is a schematic configuration diagram of the apparatus used in the following examples. In the figure, 21 is a vacuum container, and 24 is an arc power supply. The vacuum vessel 21 is divided into an upper chamber 22 and a lower chamber 23, and a mother alloy 26 arranged in a hearth 25 in the upper chamber 22 is melted by an arc to generate ultrafine particles. The generated ultrafine particles are collected by the collecting umbrella 28 by the flow of gas, pass through the nozzle 29, and are deposited on the substrate 31 arranged on the upper surface of the substrate stage unit 30. 32 and 33 are gas inlets, and 34 is an exhaust port.

An example of an operation procedure for producing ultrafine nitride particles using the apparatus 20 shown in FIG. 3 will be described. First, the valves (not shown) of the gas inlets 32 and 33 are closed, and the chamber is exhausted from the exhaust port 34. The upper and lower chambers 2
The pressure of 2, 23 is reduced to about 10 ^-3 to 10 ^-4 Torr. Next, the gas inlet 32 (or the gas inlets 32, 3
From 3), nitrogen gas (or nitrogen gas and argon gas or nitrogen gas and hydrogen gas) is introduced into the upper chamber 22, the valve (not shown) on the exhaust port 34 side is slightly opened, and the exhaust of the lower chamber 23 is restarted. To do. At this time, the amount of nitrogen gas (and argon gas or hydrogen gas) introduced from the gas introduction port 32 (and 33) and the exhaust port 34 so that the pressure in the upper chamber 22 is maintained at a predetermined nitrogen partial pressure. Adjust the displacement. With the gas pressure in the upper chamber 22 maintained at a predetermined pressure, discharge is started from the arc electrode 27 and the mother alloy 26 is heated and melted with a predetermined arc current. The ultrafine particles generated from the melted master alloy 26 are blown out from the nozzle 29 by the gas flow passing through the collecting bulk 28 and are deposited on the substrate 31.

Preparation Example 1 Using a binary alloy of 50 at% of metal aluminum and 50 at% of metal yttrium as a mother alloy, arc melting (DC 200 A) was performed in an atmosphere consisting of only nitrogen gas to prepare ultrafine particles. At this time, arc melting was performed while flowing 10 liters of nitrogen gas per minute, and the produced ultrafine particles were deposited on the substrate by the flow of gas. The mother alloy used was one in which metal aluminum and metal yttrium were melted by an arc in an argon atmosphere in a vacuum container that was the same as the vacuum container used for producing ultrafine particles in a nitrogen atmosphere, and were uniformly alloyed. The ultrafine particles produced by using the above binary alloy of 50 at% Al-50 at% Y show that the width (thickness) is about 50 from the results of observation by X-ray diffraction and transmission electron micrographs.
It was found that it is composed of hexagonal columnar or strip-shaped anisotropic particles having a size of about 100 nm to about 500 nm and isotropic particles having a diameter of about 20 to 100 nm. The anisotropic particles contained 5 to 10 atomic% of yttrium, and it was found from the results of electron beam diffraction that they were composed of a single phase of aluminum nitride. The other isotropic particles consisted of yttrium-free aluminum nitride (spherical or regular hexagonal), yttrium nitride (spherical or regular square).

Manufacturing Example 2 By the same method as in Manufacturing Example 1, as a master alloy, 50 at% aluminum-50 at% neodymium, 50 at% aluminum-50 at% cerium and 50 atm aluminum.
At% -lanthanum 50 at% of each binary alloy, arc melting (DC 200
A) was performed to prepare ultrafine particles. As a result of X-ray diffraction of the produced ultrafine particles, 50 at% Al-50 at% Nd
Alternatively, when a binary alloy of 50 at% Al-50 at% Ce was used as a master alloy, shape-anisotropic aluminum nitride ultrafine particles and neodymium nitride ultrafine particles or cerium nitride ultrafine particles containing no metallic aluminum were produced. But,
When 50 at% Al-50 at% La was used as the master alloy, metallic aluminum was contained in addition to the aluminum nitride ultrafine particles and the lanthanum nitride ultrafine particles. Further, the aluminum nitride ultrafine particles produced by using the above binary alloy of 50 at% Al-50 at% Nd (nitrogen gas pressure: 40 kPa) are very long and thin, about φ20 nm × 500 nm, as a result of observation by a transmission electron micrograph. It was a whisker-shaped ultrafine particle. As a result of the analysis, the whisker-shaped ultrafine particles were aluminum nitride single crystals, and the growth direction was the c-axis direction of the aluminum nitride crystals.

Production Example 3 Aluminum as a mother alloy 50 at% -Chromium 50 at
% Binary alloy, arc melting (DC 200 A) was performed in an atmosphere of nitrogen gas containing 4% H ₂ (nitrogen partial pressure 300 Torr) to produce ultrafine particles. At this time, arc melting was performed while flowing 10 liters of nitrogen gas per minute, and the produced ultrafine particles were deposited on the substrate in high yield (about 100 mg / min) by the flow of gas. The mother alloy used was one in which aluminum and chromium were melted by an arc in an argon atmosphere in a vacuum container which was the same as the vacuum container for producing ultrafine particles in a nitrogen atmosphere, and were uniformly alloyed.
Further, as a master alloy, 25 at% Al-75 at% Cr,
Ultrafine particles were similarly prepared using a binary alloy of 75 at% Al-25 at% Cr, metallic aluminum, and metallic chromium, respectively.

As a result of X-ray diffraction of each ultrafine particle produced,
25 at% Al-75 at% Cr or 50 at% Al-
The ultrafine particles produced by using a binary alloy of 50 at% Cr as a mother alloy are β-containing almost no ultrafine metal particles.
The particles were nitride ultrafine particles of Cr ₂ N and AlN. Especially 2
When 5 at% Al-75 at% Cr was used as the master alloy, the ceramic ultrafine particles containing about 90% of β-Cr ₂ N were produced from the result of X-ray diffraction. On the other hand, the ultrafine particles produced by using 75 at% Al-25 at% Cr as the master alloy have intermetallic compounds (Al ₈ Cr
₅ , Al ₁₃ Cr ₂ ) was contained. Also, the above 50a
The ultrafine particles produced by using the binary alloy of t% Al-50at% Cr were observed by the transmission electron micrograph and found that
It contained a large amount of ultra-fine particles of very slender ceramic whiskers having a size of about 20 to 80 nm × 1 μm. According to the analysis, this ceramic whisker is considered to be a composite ultrafine particle having a structure in which whisker-like AlN ultrafine particles extend from β-Cr ₂ N ultrafine particles.

Preparation Example 4 Aluminum as a mother alloy 25 at% -Chromium 25 at
% -Cobalt 50 at% ternary alloy, arc melting (DC 200) in an atmosphere consisting of nitrogen gas containing 4% H ₂ (nitrogen partial pressure 300 Torr) in the same manner as in Preparation Example 3.
A) was performed to prepare ultrafine particles. The mother alloy used was one in which aluminum, chromium and cobalt were melted by arc in an argon atmosphere in the same vacuum container used for producing ultrafine particles in a nitrogen atmosphere and uniformly alloyed. Further, as a master alloy, 40 at% Al-40a
t% Cr-20at% Co, 45at% Al-45at
Ultrafine particles were similarly prepared using each ternary alloy of% Cr-10 at% Co.

As a result of the X-ray diffraction of the produced ultrafine particles,
The Al-Cr-Co-based ternary alloy ultrafine particles produced by using as a base alloy, were β-Cr ₂ N (Co solid solution) and the nitride ultrafine particles AlN. In addition, the above 25 at% Al-
The ultrafine particles produced using a ternary alloy of 25 at% Cr-50 at% Co have a structure in which whisker-like or columnar ceramic ultrafine particles extend from polyhedral ultrafine particles as a result of observation by a transmission electron micrograph. It contained a large amount of composite ultrafine particles. According to the analysis, this composite ultrafine particle is considered to be a composite ultrafine particle having a structure in which whisker-like or columnar AlN ultrafine particles are extended from β-Cr ₂ N (Co solid solution) ultrafine particles.

Preparation Example 5 Aluminum as a mother alloy 10 at% -Chromium 10 at
% -Iron 80 at% ternary alloy, arc melting (DC 200 A) was performed in an atmosphere (nitrogen partial pressure 300 Torr) consisting of nitrogen gas containing 4% H ₂ using the ternary alloy in the same manner as in Preparation Example 3 to produce ultrafine particles. It was made. Incidentally, the mother alloy, in the same vacuum container as the vacuum container for producing ultrafine particles in a nitrogen atmosphere,
Aluminum, chromium and iron were melted by an arc in an argon atmosphere and uniformly alloyed. Further, as a master alloy, 5 at% Al-5 at% Cr-90a
t% Fe, 25 at% Al-25 at% Cr-50 at
% Fe, 30 at% Al-30 at% Cr-40 at%
Fe, 40 at% Al-40 at% Cr-20 at% F
e, and 45 at% Al-45 at% Cr-10 at%
Ultrafine particles were similarly produced using each ternary alloy of Fe.

As a result of observation by X-ray diffraction and transmission electron micrograph of each of the produced ultrafine particles, the ultrafine particles produced using the Al—Cr—Fe ternary alloy as the mother alloy are polyhedral ultrafine particles. The composite ultrafine particles had a structure in which whisker-like or columnar ceramic ultrafine particles were extended. According to the analysis, this composite ultrafine particle is 10a.
When a master alloy of t% Al-10at% Cr-80at% Fe is used, polyhedral ultrafine particles of α-Fe containing Cr in solid solution form whisker-like or columnar AlN.
Composite ultrafine particles having a structure in which ultrafine particles are extended.
When a master alloy of 5 at% Al-45 at% Cr-10 at% Fe is used, whisker-like or columnar AlN ultrafine particles extend from polyhedral ultrafine particles of β-Cr ₂ N in which Fe is solid-dissolved. Is considered to be a composite ultrafine particle having a structure of 30 at% Al-30 at% Cr
When a mother alloy of -40 at% Fe is used, it is considered to be a composite ultrafine particle having a structure in which whisker-like or columnar AlN ultrafine particles extend from polyhedral ultrafine particles of an intermetallic compound.

[0028]

As described above, the method for observing a sample surface according to the present invention is such that a probe having ultrafine particles having piezoelectricity attached to its tip is horizontally scanned while being in contact with the sample surface,
Since the voltage or current generated from the ultrafine particles is detected according to the pressure applied to the tip of the probe due to the unevenness of the sample surface and the sample surface is observed, the sample surface can be directly observed with high accuracy. Further, unlike STM, it is not necessary to feedback control the vertical movement of the tip of the probe in order to keep the distance between the sample surface and the tip of the probe constant, and therefore the apparatus becomes simple and inexpensive. Further, since the sample surface observing probe of the present invention has extremely fine ultrafine particles with a diameter of 5 to 100 nm attached to the tip of the probe, in addition to the sample surface observing method as described above, STM and AFM, MF
It can also be used as a probe for M or the like, and the resolution thereof can be greatly improved. Moreover, such ultrafine particles can be easily and inexpensively produced by a vapor phase method using an arc melting method or the like, and the size and shape thereof can be controlled relatively easily depending on production conditions. Furthermore, the ultrafine particles produced by such a vapor phase method do not contain impurities,
The purity is extremely high. Therefore, there is also an advantage that post processing such as ion etching and electrolytic evaporation is not required unlike the conventional processing of the tip of the probe by electrolytic polishing.

[Brief description of drawings]

FIG. 1 is a schematic enlarged view showing a basic configuration of a probe portion of a sample surface observing method of the present invention.

FIG. 2 is a graph showing changes in potential generated from ultrafine particles at the tip of a probe in the sample surface observation method of the present invention.

FIG. 3 is a schematic configuration diagram of an apparatus for producing ultrafine particles by arc melting.

FIG. 4 is a schematic diagram showing a basic configuration of an STM.

FIG. 5 is a schematic enlarged view of an STM probe portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 probe, 1a ultrafine particles, 2 piezoelectric element, 10 scanner, 11 sample support, 12 XY scanning circuit, 13
Servo circuit, 14 tunnel current amplifier, 15 memory,
16 computers, 17 CRTs, 18 CRTs
Screen, S sample

Claims (8)

[Claims] 1. A probe having ultrafine particles having piezoelectricity attached to its tip is horizontally scanned while being in contact with the surface of the sample, and the above-mentioned ultrafine particles are applied in accordance with the pressure applied to the tip of the probe due to unevenness of the sample surface. A sample surface observing method, which comprises observing a surface of a sample by detecting voltage or current generated from fine particles. 2. The ultrafine particles are aluminum nitride ultrafine particles, aluminum nitride ultrafine particles in which a rare earth element is solid-soluted, ultrafine particles composed of a composite phase of aluminum nitride and rare earth nitride, aluminum nitride and metal, intermetallic compound or nitride. Al-M ¹ -N consisting of composite phase of natural ceramics
(However, M ¹ represents at least one kind of metal element selected from the group consisting of Cr, Fe, Co and Ni) Based on ultrafine particles, aluminum nitride and metal, intermetallic compound or composite phase of nitride ceramics al-M ² -M ³ -N
(However, M ² is at least one metal element selected from the group consisting of Cr, Co and Fe, and M ³ is Au, Cu, D
y, Er, Ga, Ge, Gd, Hf, Ho, Lu, M
n, Mo, Nb, Nd, Ni, Pr, Re, Sb, S
c, Si, Sn, Ta, Tb, Ti, Tm, V, W,
At least one selected from the group consisting of Y, Zn and Zr
Ultrafine particles of various metal elements), barium titanate ultrafine particles, PbZrO ₃ -PbTiO ₃ based solid solution ultrafine particles, lead titanate ultrafine particles, SiO ₂ ultrafine particles, lithium niobate ultrafine particles, lithium tantalate ultrafine particles, and Z
The method according to claim 1, which is an ultrafine particle selected from the group consisting of nO ultrafine particles. 3. The method according to claim 1, wherein the ultrafine particles are rod-shaped, needle-shaped, whisker-shaped, or spherical ultrafine particles having a diameter of 5 to 100 nm. 4. A probe for observing a sample surface, wherein ultrafine particles having a diameter of 5 to 100 nm are attached to the tip of the probe. 5. The probe according to claim 4, wherein the ultrafine particles have a diameter of 5 to 50 nm. 6. The probe according to claim 4, wherein the ultrafine particles are rod-shaped, needle-shaped, whisker-shaped, or spherical ultrafine particles. 7. The probe according to claim 4, wherein the ultrafine particles have piezoelectricity, conductivity, or magnetism. 8. The ultrafine particles are aluminum nitride ultrafine particles, aluminum nitride ultrafine particles in which a rare earth element is solid-soluted, ultrafine particles composed of a composite phase of aluminum nitride and rare earth nitride, aluminum nitride and metal, intermetallic compound or nitride. Al-M ¹ -N consisting of composite phase of natural ceramics
(However, M ¹ represents at least one kind of metal element selected from the group consisting of Cr, Fe, Co and Ni) Based on ultrafine particles, aluminum nitride and metal, intermetallic compound or composite phase of nitride ceramics al-M ² -M ³ -N
(However, M ² is at least one metal element selected from the group consisting of Cr, Co and Fe, and M ³ is Au, Cu, D
y, Er, Ga, Ge, Gd, Hf, Ho, Lu, M
n, Mo, Nb, Nd, Ni, Pr, Re, Sb, S
c, Si, Sn, Ta, Tb, Ti, Tm, V, W,
At least one selected from the group consisting of Y, Zn and Zr
Ultrafine particles of various metal elements), barium titanate ultrafine particles, PbZrO ₃ -PbTiO ₃ based solid solution ultrafine particles, lead titanate ultrafine particles, SiO ₂ ultrafine particles, lithium niobate ultrafine particles, lithium tantalate ultrafine particles, and Z
The probe according to any one of claims 4 to 7, which is an ultrafine particle selected from the group consisting of nO ultrafine particles.