JPH0773145B2 - Method for producing electronic functional device using ultrafine particles - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an aggregate or condensate of tens or tens of thousands of ultrafine particles of atoms or molecules on a solid surface with a uniform particle size and regularity up to several nanometers or less. Are arranged with regularity at intervals of, and the regularity of the arrangement or the atomic / intermolecular binding mechanism (structure) inside the condensate is controlled and converted by changes in the external field such as electric field, magnetic field, temperature, etc. Change the electrical response characteristics,
It is intended to provide a solidification generation method of electronic functional elements used for ultra-high density information processing and storage, and the fields to which this can be applied are optoelectronic computers, chemical sensors and other information signal processing, and electronics for storage. It is an engineering element.

[0002]

2. Description of the Related Art In today's electronics, electronic devices for all kinds of signal processing and storage depend on the control of the ultrafine structure of semiconductors and the high level of high-density integration technology of the devices. You can think of it.

[0003]

However, the precision of the fine processing is currently limited to about 0.1 μm in practical use, and the expectation for a further processing technology is the principle (use of photoresist, use of photoresist). Wavelength of processing light flux
From the perspective, it seems almost impossible. Therefore, in principle, it is necessary to create completely different electronic function integrated devices for high-density and ultra-high-density integration.

[0004]

The present invention has been conceived in order to solve the above-mentioned problems.
Any one or two or more selected from a Group 4 element consisting of e and C, a Group 5 element consisting of As, Sb and Bi, and a group 6 element consisting of S, Se and Te. The ultra-fine particles of are dissolved in an organic solvent and dried while controlling the concentration and temperature to separate ultra-fine particles of different sizes, each of which has a size of several nm to several nm. The particles are regularly arranged and solidified, and the ultrafine particles located at a specific position among the ultrafine particles arranged on the solid surface of the substrate are removed by an external field of an electric field, a magnetic field, or light. An electronic functional element using the ultrafine particle state characterized by controlling the structure and arrangement of the ultrafine particles by an external field by moving or changing the structure and properties of the ultrafine particles. It is in the generation method.

[0005]

The points of the present invention can be summarized by the following items. The arrangement of the semiconductor or metal ultrafine particles (microclusters) on the solid surface according to the present invention is the number of condensed atoms (molecules) of each ultrafine particle (microcluster) and the solid surface of the ultrafine particles. The electronic function depends on the regularity of the sequence in.

The electronic function of the ultrafine particles can be detected by the area of the array system. In this case, the sensitivity of the optical system or the voltage and current detection sensitivity can be reduced to the limit. For example, if the lattice of ultrafine particles is regularly arranged on the surface of single crystal Si or graphite at intervals of several nm, the presence and change of the lattice system in the current photon response or current sensitivity can be detected. The minimum area is 10
It is about 0 nm × 100 nm. If the array structure changes in a binary manner (Yes or No) within this area, this lattice system has a storage capacity of several terabits / μm ² .

If the detection sensitivity of the optical response by the ultrafine optical spectroscopy or the STM tunnel current sensitivity is improved, the storage density or the signal processing density in the previous section will be correspondingly increased and improved.

The electronic properties and chemical reaction activity of microclusters are significantly changed depending on the number (size) of condensed atoms / molecules. Therefore, it is possible to control the physical electronic function, the stability, and the activity of the reaction (including the catalyst) in the ultra-small space by changing not only the structure change of the microcluster but also the size.

The feature of the present invention consists of the following three steps. (1) a step of dissolving the ultrafine particles in an organic solvent and drying while controlling the concentration and temperature to separate the ultrafine particles having different sizes, and solidifying and producing each in a single size state, 2) A step of arranging ultrafine particles of uniform size on the solid surface of the substrate with regularity, and (3) Among ultrafine particles arranged on the solid surface, the fine particles at a specific position are subjected to an external field ( It consists of the steps of operating (removing or moving, or changing the structure or properties of the ultrafine particles themselves) by an electric field, magnetic field, light).

The features of the above methods (1) to (3) are as follows. Features of (1): a) The extraction efficiency is higher than that of the conventional ultrafine particle isolation and extraction method. b) Only ultrafine particles of a size that exists stably in the atmosphere can be extracted. Many ultrafine particles are generally chemically unstable, but when dissolved in a solution, only a stable size remains in the solution and isolation becomes possible.

Feature (2): The size of ultrafine particles is several nm
In (nanometer), considered to be the smallest size of a substance.
The properties of materials such as metals, semiconductors, magnetic materials and superconductors depend on their size. The property of matter does not appear with one atom. Appears from a size of several nm. A new material can be created by regularly arranging this so-called minimum size substance. In particular, as an electronic device, a device having the smallest size and the highest integration density can be produced.

Feature (3): Not only the elements with the smallest size are regularly arranged to increase the degree of integration, but also the structure and arrangement state of the ultra-fine particles are controlled by an external field, so that an ultra-high density memory element and an arithmetic element can be obtained. Electronic functional devices such as optoelectronic devices can be made.

The above three means methods will be described in more detail as follows. (1) Manufacturing method of ultra-fine particles of uniform size A group of atoms (microclusters) formed by binding several to several thousand atoms / molecules is called ultra-fine particles, and the size determined by the number of atoms is the size. Call. Some ultrafine particles are soluble in organic solvents such as benzene and carbon disulfide. Normally, when a metal is dipped in an acid, the metal atoms are decomposed and dissolved one by one, and they do not exist as a group of atoms like ultrafine particles. However, ultra-fine particles made of Group 4, Group 5, and Group 6 elements, such as Group 6 sulfur (S (n)
, N = 2,3,4,5,6, ----- 50) Selenium, Se (n) (atomic number n = 2,3,4,5,6, ----- 5)
0), Te (n) (the number of atoms n = 2 ----- 50) and the like are present in the solvent in respective sizes. The ultrafine particles in the solution can be isolated and extracted with the same size by appropriately setting the concentration and temperature of the solution and by the method of liquid chromatography.

By this method, ultrafine particles of one kind or several kinds of elements such as carbon of group IV, silicon, germanium, phosphorus of group IV, arsenic, antimony, sulfur of group VI, selenium and tellurium are prepared in each size. It was isolated and extracted with.

(2) Solid Surface Arrangement of Ultrafine Particles The sample prepared by the above method (1) is vaporized by a method such as vacuum vapor deposition, laser irradiation, electron beam irradiation, ion bombardment, and deposited on a substrate. Substrates include: -Solid semiconductors such as graphite, silicon and germanium, surfaces of metalloid elements-Surfaces of various metals such as noble metals and transition metals-Surfaces of Group III-IV compound semiconductors such as gallium arsenide and aluminum arsenide -Surfaces of Group III-VI compound semiconductors such as cadmium sulfide and zinc selenide-Layered semiconductors such as molybdenum sulfide and tantalum sulfide, and transition metal surfaces can be used. As the array structure of ultrafine particles, a square lattice, a rectangular lattice, or a triangular lattice can be obtained. The above array state was confirmed by Raman scattering spectroscopy, electron energy loss spectroscopy, and scanning tunneling microscope.

(3) Control of Structure and Arrangement State of Ultrafine Particles Deposited on Solid Surface By irradiating a sample on which ultrafine particles are vapor-deposited with a laser, electron irradiation from a sharply pointed metal probe, and ion bombardment. , All ultra-fine particles or a specific part (at least one ultra-fine particle)
Controlled the structure and sequence status of. By controlling the laser light intensity, or the current and voltage of electrons and ions,
The conditions for each type and combination of types of ultrafine particles and substrate in (2) were determined.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram for explaining the general configuration principle of the present invention. Reference numeral 1 denotes a solid surface of the substrate, and ultrafine particles 2 on the solid surface of the substrate 1 are arranged at predetermined positions,
The arrangement state or the internal structure of the ultrafine particles 2 is changed by the probe 3 or the external field 4 such as light, particle beam, electric field, magnetic field, temperature, etc., and the state change is also changed by the probe 3 or the external field response detection unit 5. To detect the response to the external field. In FIG.
2A and 2B show a state in which the ultrafine particles 2A change their structure like 2B when an external field is applied.

Experimental Example Structure and Stability of Microcluster Lattice Structure (1) Outline of Experiment This experiment is an experimental consideration on adsorption and interaction of microclusters on a crystal surface forming a regular array. Microclusters are produced and deposited by laser ablation or thermal evaporation in a monolayer coverage on the c-plane of a carbon substrate.
Its structure and stability are determined by mass spectrometry, optical measurement and scanning tunneling microscopy (ST
It can be analyzed by M). The results for C, Sb and Se show that micro-clusters of dozens to hundreds of atoms each tend to deposit on the substrate in random shapes and positions. If the coating on the substrate approaches a monolayer, cluster aggregation or coalescence begins. Generally speaking, our STM measurements do not show reliable evidence of special lattice structures or defects on the substrate at the preferred deposition locations of the clusters.
However, in some cases, clusters of approximately the same size separate and regularly deposit in one or two dimensions. For example, S
At e, some STM images show a two-dimensional rectangular lattice consisting of Se clusters in an 8-ring shape.
The structure of point defects and grain boundaries found in rectangular lattices suggests that the regular arrangement is achieved by interactions in clusters as well as interactions with substrate lattices.

The cluster aggregate material constitutes a new type of condensate. Microcluster lattice organization is one of the simplest and well-defined forms of atomic assembly. For a lattice-forming microcluster, the microcluster must be chemically stable in its condensed phase. Microclusters that strongly bond internally and act weakly on each other condense on the solid surface of the substrate like molecular crystals. The sample is a crystal of Se ₈ 1, C ₆₀ 2 and has a Hu ₅₅
It is a coordination stable metal cluster such as 3. If solid 4
Microclusters form a regular lattice if they are periodically supported in a chemically stable environment on the surface of, or in the interstices of layered materials, or in cages of encapsulating compound 5. Microclusters on the solid surface of the substrate show a variety of textures consisting of different combinations of microclusters and surfaces. A survey of such organizations will provide basic and unambiguous information on the material interactions of cluster clusters and cluster hosts in cluster assembly materials. In this experiment, C, on the cleaved surface of highly oriented pyrolytic graphite at room temperature, was investigated in order to investigate the possibility of creating a two-dimensional microcluster lattice texture.
This is an experimental study on the adsorption of Sb and Se microclusters. Microclusters are produced by excimer laser irradiation (KrF) in the 10 mJ power range at the component target.

(2) Experimental Results and Discussion 2-1 Microcluster Structure on Graphite A possible approach to create a regular arrangement of microclusters is to attach strongly bound microclusters to a chemically inert surface. Is to deposit. In this system, microclusters may not appreciably change their chemical and physical properties from their isolated state in free space. Therefore, I decided to study the interaction of the microclusters with the substrate in the free space.

The vaporization of the elements of the fourth, fifth and sixth groups by heat or laser causes various forms of microclusters in vacuum. Many experimental and theoretical investigations show that the carbon clusters C _n 's for n <10 form straight chains.
The mass spectrum of carbon clusters produced by laser ablation indicates that C ₃ is the predominant species in the vapor. Figure 2 shows a typical ST of carbon clusters deposited on graphite.
The M image is shown. The figure shows a flat and random arrangement of carbon atoms on a graphite substrate. It is not currently clear whether carbon chains stick well to the graphite surface. Since the kinetic energy of carbon clusters is several eV excess in the experimental laser ablation method, carbon clusters may be crushed on the graphite surface.

FIG. 3 shows an STM image of Sb clusters deposited on the graphite surface by laser ablation. Most species of Sb vapor mass spectrum is Sb ₄
Indicates that it is 11. Raman measurements of Sb vapor frozen in an inert gas matrix show that Sb ₄ is in the tetragonal form. Our STM Sb photographs do not give a clear atomic image of the microclusters compared to the carbon ones in FIG. 2, but ours are STM
It is clear that there is no single separated Sb tetramer (tetramer) in the image.

2-2 Deposition Position of Microclusters on Graphite Substrate Although the graphite substrate surface is chemically inactive, surface defects such as atomic depletion, crystal defects on the surface such as steps and kinks are responsible for microcluster deposition. Acts as a stable position. These positions can be used to deposit microclusters of regular sequence. FIG. 4 shows Sb clusters deposited with a single shot of an excimer laser on graphite with steps. It can be seen that the Sb clusters are deposited indiscriminately and do not show a preferred deposition position for the resolution of the inventor's STM measurement. If the coverage of the microclusters is increased by applying more laser pulses to the starting material target, the agglomeration of the microclusters begins.

2-3 Micro-cluster lattice of Se molecules Selenium (Se) is known to form both rings and chains in solid and liquid solutions. X-ray analysis shows that monoclinic selenium is Se
_It shows that ₈ rings (see FIG. 7) are formed. Other crystals are S
It is suggested that it consists of the e ₆ ring. S in CS ₂ solution
The e ring dissolves, the Se chain does not.

The solvent-extracted Se powder was deposited on a graphite substrate at 300 ° C. in vacuum. The STM image in Figure 5 has a diameter of 5.
It shows that the 2 A clusters are arranged in a rectangular alignment with a lattice constant of 7.38 A x 8.52 A. The diameter is comparable to 5.26A found for Se ₈ rings in monoclinic crystals. The lattice constant corresponds to three times the distance between the two sides and the isosceles of the hexagon in graphite. These dimensions are such that the Se ₈ rings are arranged in a rectangular lattice in the axial direction of the two sides and the isosceles on the graphite surface. Another STM image shown in FIG. 6 shows domains and lattice defect structures. The domain structure comes from the fact that there are three different orientations of the hexagonal lattice, each rotating by 120 ° on a rectangular lattice. Many domains show random sequences at their boundaries. As a result, we show that both cluster-cluster and cluster-substrate interaction are important for creating micro-cluster texture.

(3) Conclusion Microclusters of the fourth, fifth and sixth group elements are deposited on the graphite surface. The results of this experiment show that microclusters with strong intracluster coupling and weak cluster interactions are suitable for creating microcluster lattice texture. Cluster-substrate interaction is Se
It is clear from the fact that the cluster period is suitable for the host graphite hexagonal lattice.

[0027]

INDUSTRIAL APPLICABILITY In the present invention, the arrangement of the ultrafine particle array system is controlled by the external field application and the internal structure of each ultrafine particle is changed, and the optical response and current (electric field application) and light induced by the change are changed. Since the change of the electric current and further the change of the chemical reaction activity can be changed within a very small area, this effect can be associated with the information signal of interest and applied to the storage and processing thereof.

There are three points of the present invention. (1) Development of a method in which ultrafine particles of different sizes are separated by dissolving the ultrafine particles in an organic solvent and drying while controlling the concentration and temperature, and solidifying each in a single size state.

(2) It has been found that ultra-fine particles of uniform size are regularly arranged on the solid surface of the substrate.

(3) Out of the ultrafine particles arrayed on the solid surface, the fine particles at a specific position are subjected to an external field (electric field, magnetic field, light).
We have developed a method to manipulate (remove or move, or change the structure and properties of the ultra-fine particles themselves).

The characteristics of the above methods (1) to (3) are as follows. Features of (1): a) The extraction efficiency is higher than that of the conventional ultrafine particle isolation and extraction method. b) Only ultrafine particles of a size that exists stably in the atmosphere can be extracted. Many ultrafine particles are generally chemically unstable, but when dissolved in a solution, only a stable size remains in the solution and isolation becomes possible.

Feature (2): The size of ultrafine particles is several nm
In (nanometer), considered to be the smallest size of a substance.
The properties of materials such as metals, semiconductors, magnetic materials and superconductors depend on their size. The property of matter does not appear with one atom. Appears from a size of several nm. A new material can be created by regularly arranging this so-called minimum size substance. In particular, as an electronic device, a device having the smallest size and the highest integration density can be produced.

Feature (3): Not only the elements having the minimum size are regularly arranged to increase the degree of integration, but also the structure and arrangement state of the ultra-fine particles are controlled by an external field, so that an ultra-high density memory element and an arithmetic element can be obtained. Electronic functional devices such as optoelectronic devices can be made.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for specifically explaining the principle of the present invention.

FIG. 2 is a photographic diagram showing an image of a crystal structure measured by scanning tunneling microscopy (STM).

FIG. 3 is a photograph showing a measurement image of a crystal structure by scanning tunneling microscopy (STM).

FIG. 4 is a photographic diagram showing an image of a crystal structure measured by scanning tunneling microscopy (STM).

FIG. 5 is a photographic diagram showing an image of a crystal structure measured by scanning tunneling microscopy (STM).

FIG. 6 is a photograph showing a measurement image of a crystal structure by scanning tunneling microscopy (STM).

FIG. 7 is a diagram showing a ring crystal structure of Se8.

[Explanation of symbols]

1 Substrate 2 Ultra-fine particles (micro-cluster) 3 Probes 2A, 2B Model diagram showing the state before and after structural change of ultra-fine particles 4 External field application part of light, particle beam, electric field, magnetic field, temperature, etc. 5 External field response detector

Claims (1)

[Claims] 1. A Group IV element made of any one of Si, Ge, C, a Group V element made of As, Sb, Bi, S,
Dissolving any one kind or two or more kinds of ultrafine particles selected from the Group 6 element consisting of Se or Te in an organic solvent,
By drying while controlling its concentration and temperature,
Separation of ultrafine particles of different sizes, and arraying them in a regular size with a size of several nanometers or more and several nanometers in a single size, solidification, and ultra-fine particles arrayed on the solid surface of the substrate. The ultrafine particles at a specific position among the fine particles are removed or moved by an external field of an electric field, a magnetic field, or light, or an operation is performed to change the structure and properties of the ultrafine particles. A method for producing an electronic functional device using an ultrafine particle state, characterized in that the structure and arrangement of particles are controlled by an external field.