JP3326293B2 - Inorganic ultra-thin flake and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ultra-thin 100-.mu.m-thick thin piece made of a first inorganic substance, wherein a second inorganic substance harder than the first inorganic substance is adhered to one end of the very thin section, and an opposite end thereof. In particular, the present invention relates to an ultra-thin inorganic flake whose part is supported on a substrate and a method for producing the same, and more particularly, to an ultra-thin inorganic flake such as a semiconductor, a magnetic material, a ferroelectric, and a superconductor for a transmission electron microscope (TEM) sample and a method for producing the same It is about.

[0002]

2. Description of the Related Art A sample of a transmission electron microscope (TEM) by an ion milling method is manufactured by an ultramicrotome method,
Compared to other methods such as electrolytic polishing, a specific portion can be observed from a specific direction without being restricted by the shape, hardness, conductivity, and the like of the sample, and thus is widely used.

However, the preparation of a cross-sectional sample requires complicated pre-processing up to ion milling, and the sample preparation time is long, and one to two samples per week are limited.

[0004] In order to shorten the sample preparation time,
A cross-sectional sample preparation method (ion shadow method) was proposed (The Japan Institute of Metals, 1994
Characterization of Local Area (II) ”, P60-
64).

[0005] In this ion shadow method, a sample is subjected to T
Cut to the size shown in FIG. 10 (length 3 mm, width 0.3 mm to 0.2 mm or less) so as to enter the EM sample holder.

When the thickness of the silicon substrate is less than 0.5 mm, it is difficult to load the TEM holder, so a dummy silicon plate is bonded with an instant adhesive.

At the time of cutting a sample, in order to reduce damage to the film surface, the film surface is fixed to a slide glass with wax and cut.

Next, after cleaning the surface of the sample, as shown in FIG. 11, diamond powder is dispersed and adhered to the surface of the multilayer film. The size of the diamond powder depends on the thickness (cross-section depth) of the multilayer film to be observed and the material of the film (ion etching rate)
0.2 μm to 1.0 μm. The diamond powder is obtained by centrifuging a commercially available diamond slurry (at 10,000 rpm for several minutes) to separate it from the ruplication solution, and washing it several times with a solvent such as acetone or Diflon. After the washing solvent is dried, it is used in ethanol.

Next, as shown in FIG. 12, argon (Ar) ions are irradiated perpendicularly to the surface of the multilayer film to which the diamond powder is attached. Accelerating voltage 3-5 kV, ion current 0.5
Irradiate with mA for 3-7 minutes. Since diamond has a low ion milling speed, only the multilayer film and the silicon substrate are deeply etched as shown by the dotted line. As shown in FIG. 13, the current density of argon ions has a Gaussian distribution on the sample surface, and the beam diameter is about 1 mmφ in half width.
Therefore, the center of the sample is etched deeply, and both ends of the sample are etched shallowly.

Although the TEM sample holder is generally used for a sample of 3 mmφ, it is convenient for observation when the sample produced by the ion shadow method is inserted so as to bridge the sample in the tilt axis direction of the eucentric goniometer. .

[0011]

DISCLOSURE OF THE INVENTION As a result of studying the above prior art, the present inventor has found the following problems.

As shown in FIG. 5, a sample prepared by the conventional ion shadow method proposed above has a columnar thin film and is thick, so that an atomic image can be observed with a transmission electron microscope (TEM). Did not.

In other methods such as electrolytic polishing, it is extremely difficult to reduce the thickness of the film from 1 mm to 10 μm by polishing, and there is a problem that it takes about two days.

An object of the present invention is to provide an inorganic material having a thickness of 10%.
An object of the present invention is to provide an inorganic thin flake in which an inorganic material having a higher hardness than the inorganic material is attached to one end of the ultrathin flake of 0 ° to 200 °, and the opposite end is supported on a substrate.

Another object of the present invention is to provide a technique capable of shortening a sample preparation time for observing an atomic image of a cross section of a thin film with a TEM.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0017]

The following is a brief description of an outline of a typical invention among the inventions disclosed by the present application.

(1) A first inorganic thin film having a predetermined thickness is formed on a substrate, and a second inorganic powder or wire harder than the first inorganic material is formed on one end of the first inorganic thin film. After the columnar inorganic material is deposited, the surface of the first inorganic thin film to which the hard second inorganic powder or the linear inorganic material is attached is vertically irradiated with an ion beam to obtain a columnar body of the first inorganic thin film. A method for producing an inorganic ultra-thin flake, comprising irradiating an ion beam at an angle in the range of 10 to 20 degrees from the back side of the first inorganic thin film to ultra-thin the columnar body.

(2) Thickness of 100 ° made of the first inorganic substance
A second inorganic substance, which is harder than the first inorganic substance, adheres to one end of the ultra-thin flake of about 200 °, and the opposite end is the substrate surface.
An inorganic ultra-thin flake produced by the production method as described in (1) above, which is supported on one end side of the inorganic substance.

(3) The first inorganic ultra-thin flake is a substrate surface
2. The inorganic ultra-thin flake according to the above (2), wherein a plurality of flakes are provided upright on one end side of the inorganic material.

[0021]

According to the present invention, since the inorganic ultra-thin flakes are made of the first inorganic substance and have a thickness of 100 to 200 mm,
An atomic image of a cross section of the thin film of the first inorganic substance can be observed with a transmission electron microscope (TEM).

As a result, a highly reliable high-resolution atomic image of the cross section of any inorganic thin film can be obtained in a short time. This can greatly contribute to the promotion of research and development of thin-film electronic devices.

According to the method for manufacturing an inorganic ultra-thin flake of the present invention, an inorganic thin film having a predetermined thickness is formed on a substrate, and a second hard material, which is harder than the first inorganic material, is formed on one end of the inorganic thin film.
Of the first inorganic thin film to which the hard inorganic powder or the linear inorganic material is attached, and vertically irradiating the front surface of the first inorganic thin film to which the hard inorganic powder or the linear inorganic material is attached, and thereafter, the back side of the first inorganic thin film 10-2 ion beam
By irradiating at an angle in the range of 0 degree, it is possible to obtain an ultrathin flake of the first inorganic substance having a thickness of 100 ° to 200 ° in a short time.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, the ultra-thin flake of one embodiment according to the present invention is made of a first inorganic material having a thickness of 100 to 20 mm.
A second inorganic substance 2 harder than the first inorganic substance is attached to one end of the ultrathin piece 1 of 0 °, and the opposite end is supported on the substrate 3.

The ultra-thin film 1 is made of, for example, an ultra-thin flake of any one of YBCO oxide superconductor thin film, semiconductor thin film, diamond thin film, magnetic thin film (garnet thin film), dielectric thin film and the like. I have.

The second inorganic substance 2 is made of an inorganic substance which is harder than the first inorganic substance of the ultra-thin flake 1 made of the first inorganic substance and having a thickness of 100 to 200 °, preferably a hard inorganic substance having a hardness of 8 or more. (For example, diamond).

The substrate 3 is, for example, a single crystal substrate made of SrTiO ₃ , MgO, LaAlO ₃ , Si, GaAs
s and GGG.

In this embodiment, a plurality of ultra-thin pieces 1 are erected on the substrate 3, but one ultra-thin piece may be used.

Next, a method of producing the inorganic thin piece of the present embodiment will be described.

As shown in FIG. 2, for example, SrTiO ₃
On a single crystal substrate 11 made of (100), a YBCO oxide superconductor thin film 12 having a predetermined thickness is deposited by a vapor deposition method (another method may be used, for example, laser ablation, sputtering, MBE, MOCVD, LPE). Etc.)
And cut it into a width of 100 μm to form a sample (thin film with substrate 11) 13. At the time of cutting the sample 13, the film surface is fixed to a slide glass with wax to cut the film surface in order to reduce damage to the film surface.

Next, as shown in FIG. 3A, a predetermined amount of 1 μm to 2 μm diamond powder 22 is placed on a glass plate 21 and an alcohol or acetone solution is injected into the glass plate 21. Press and rub to disperse. Filter paper may be used instead of the glass plate 21.

As shown in FIG. 3C, a predetermined amount of a magnetic powder (for example, iron fine particles) 31 of 1 μm to 2 μm is placed on the glass plate 21 and the magnet 3 is placed under the glass plate 21.
The magnetic powder (for example, iron fine particles) 31 may be uniformly dispersed by moving the magnetic powder 2.

Next, after cleaning the surface of the oxide superconductor thin film 12 of the sample 13, the diamond powder 22 dispersed on the glass plate 21 is washed with the oxide powder as shown in FIG. It is attached to one side of the surface of the superconductor thin film 12.

FIG. 4 shows an oxide superconductor thin film 1 of this embodiment.
FIG. 5 is a perspective view showing an external configuration of an ion milling holder for forming an extremely thin piece of FIG. 2, FIG. 5 is a cross-sectional view taken along line XX of FIG. 4, and FIG. 6 is a configuration of a copper grid (Copper grid) plate. FIG.

4 to 6, reference numeral 51 denotes an ion milling holder main body (made of titanium), 52 denotes a copper grid (Copper grid) plate, 53 denotes a cover, 54 denotes a grid, and 55 denotes fixing screws.

As shown in FIG. 5, the sample 13 to which the diamond powder 22 has been attached is placed on a copper grid (Copper grid) plate 52, and the copper grid (Copper grid) plate 52
Is set on the ion milling holder main body 51, and the cover 53 is mounted thereon with fixing screws 55.

Then, as shown in FIG. 7A, the film surface of the sample 13 on which the diamond powder 22 is adhered is vertically irradiated with argon (Ar) ions. Acceleration voltage 3-5
Irradiate for 3-7 minutes at kV, ion current 0.5 mA. Since diamond has a low ion milling speed, as shown by the dotted line in FIG.
Only the substrate 2 and the single crystal substrate 11 are deeply etched to form the pillars 14 as shown in FIG.

Next, as shown in FIG. 7 (d), an argon (Ar) ion beam is irradiated for about 10 minutes from the back side of the film surface of the sample 13 on which the diamond powder 22 is adhered, at an angle of 15 degrees. The thickness of inorganic material 1
An ultra-thin piece 15 of 00 ° to 200 ° is formed.

As described above, according to the ultrathin piece of the oxide superconductor thin film 12 of the present embodiment, the ultrathin piece 15 made of the oxide superconductor (first inorganic substance) and having a thickness of 100 to 200 mm. Therefore, an atomic image of the cross section of the thin film can be observed with a transmission electron microscope (TEM). 8 and 9 (a-axis direction portion of FIG. 8: a
(enlarged photograph of -axis part).

8 and 9, a-axis is a
The axial portion, c-axis, is the c-axis portion, and the white portions are atoms.

By observing an atomic image of a cross section of the thin film of the oxide superconductor thin film 12 with a transmission electron microscope (TEM), a high-resolution atomic image of the thin film cross section of the oxide superconductor thin film 12 (all inorganic substances) is shortened. Since it can be reliably obtained in a short time, it can greatly contribute to the promotion of research and development of oxide superconductor devices (all thin film electronic devices).

Further, according to the method for manufacturing an ultra-thin flake of this embodiment, the oxide superconductor thin film 12 having a predetermined thickness is formed on the substrate 11.
Is formed, diamond (hardness 10) powder 22 is adhered to one end of the thin film 12, and the front surface of the thin film 12 is irradiated with an argon (Ar) ion beam vertically, and then from the back side of the inorganic thin film. Argon (Ar) ion beam 1
By irradiating at an angle in the range of 0 to 20 degrees, the thickness of the oxide superconductor thin film 12 can be reduced in a short time.
It is possible to obtain a very thin piece 15 of 0 to 200 degrees.

As described above, the present invention has been specifically described based on the embodiments. However, it is needless to say that the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. Absent.

[0045]

The effects obtained by typical ones of the inventions disclosed by the present application will be briefly described as follows.

The thickness of the first inorganic material is from 100 to 20.
Since it is an extremely thin piece of 0 °, an atomic image of a cross section of the thin film can be observed with a transmission electron microscope (TEM).

Thus, a high-resolution atomic image of a cross section of any inorganic thin film can be obtained in a short time and with high reliability. Thereby, the present invention can greatly contribute to promotion of research and development of thin-film electronic devices.

Further, it becomes possible to realize various quantum effect devices using ultrathin pieces having a thickness of 100 to 200 mm, and it is considered that they play an important role in the development of electronic devices having new functions.

According to the method for producing an extremely thin inorganic material of the present invention, a first inorganic thin film having a predetermined thickness is formed on a substrate,
A second inorganic powder or a linear inorganic substance harder than the first inorganic substance is attached to one end side of the first inorganic thin film, and the second hard inorganic powder or the linear inorganic substance is attached to the first inorganic thin film. By irradiating the ion beam perpendicularly to the front surface of the first inorganic thin film and thereafter irradiating the ion beam from the back surface side of the first inorganic thin film at an angle in the range of 10 to 20 degrees, the ion beam is irradiated in a short time. It is possible to obtain an ultrathin flake having a thickness of 100 ° to 200 ° made of one inorganic substance.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the configuration of an extremely thin piece according to one embodiment of the present invention.

FIG. 2 is a diagram for explaining a method for producing an ultra-thin piece according to the present embodiment.

FIG. 3 is a diagram for explaining a method for producing an ultra-thin piece according to the present embodiment.

FIG. 4 is a perspective view showing an external configuration of an ion milling holder for forming an extremely thin piece according to the present embodiment.

FIG. 5 is a sectional view taken along line XX of FIG. 4;

FIG. 6 is a plan view showing a configuration of a copper grid (Copper grid) plate of the present embodiment.

FIG. 7 is a diagram for explaining a method for producing an ultra-thin piece according to the present embodiment.

FIG. 8 is a photograph of a sample of the present example taken with a transmission electron microscope.

9 is an enlarged transmission electron micrograph of a portion in the a-axis direction (a-axis portion) of FIG. 8;

FIG. 10 is a diagram for explaining a problem of the related art.

FIG. 11 is a diagram for explaining a problem of the related art.

FIG. 12 is a diagram for explaining a problem of the related art.

FIG. 13 is a diagram for explaining a problem of the related art.

[Brief description of reference numerals]

DESCRIPTION OF SYMBOLS 1 ... Ultra thin piece, 2 ... Second inorganic substance, 3 ... Substrate, 11 ... Single crystal substrate, 12 ... Oxide superconductor thin film, 13 ... Sample, 15
... ultra-thin pieces, 21, 23 ... glass plate, 22 ... diamond powder, 31 ... magnetic powder (for example, iron fine particles), 32 ... magnet, 51 ... ion milling holder body, 52 ... copper grid plate, 53 ... cover, 54 ... Grid, 55 ... fixing screws.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-18873 (JP, A) JP-A-5-54327 (JP, A) JP-A-6-207891 (JP, A) JP-A-62-1987 274237 (JP, A) JP-A-6-132001 (JP, A) Yoshioka Tadanori, "Characterization of Local Regions (2)", Seminar Textbook of the Institute of Metals, Japan, Japan Institute of Metals, September 1994 March 5, p. 59-64 (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 1/00-1/44 JICST file (JOIS)

Claims (3)

(57) [Claims] 1. A first inorganic thin film having a predetermined thickness is formed on a substrate, and a second inorganic powder or a linear harder than the first inorganic material is formed on one end of the first inorganic thin film. After depositing an inorganic substance and vertically irradiating the surface of the first inorganic thin film to which the hard second inorganic powder or the linear inorganic substance is attached with an ion beam to obtain a columnar body of the first inorganic thin film, Ion beam is applied from the back side of 1 inorganic thin film
A method for producing an inorganic ultrathin flake, characterized in that the columnar body is made ultrathin by irradiating it at an angle in the range of 0 to 20 degrees. 2. A thickness of 100 to 2 made of a first inorganic substance.
A second inorganic substance, which is harder than the first inorganic substance, adheres to one end of the ultra-thin piece of 00 °, and the opposite end is supported on one end of the substrate surface. Item 1
5. An inorganic ultra-thin flake produced by the production method described in 1). 3. The inorganic ultra-thin flake according to claim 2, wherein a plurality of the first inorganic ultra-thin flakes are erected on one end of the substrate surface.