JPWO2017130974A1 - Silicon cluster super lattice - Google Patents

Abstract

Silicon clusters are used to make conductors, semiconductors, insulators, etc. feasible, and to provide vacuum isolation windows with semiconductor elements and ultra-thin high-strength thin films. A silicon cluster characterized in that a silicon cluster having a diamond crystal structure is arranged in the shape of a body-centered cubic lattice structure having a lattice constant approximately four times the lattice constant of the silicon crystal structure to form a three-dimensional three-dimensional lattice. It is a super lattice. In addition, a silicon cluster having a diamond crystal structure is arranged in a shape of a body-centered cubic lattice structure having a lattice constant of 2.043 nm to 2.172 nm to form a three-dimensional three-dimensional lattice. It is a super lattice.

Description

  The present invention relates to a silicon cluster super lattice having a super lattice structure constituted by silicon clusters, and a semiconductor device, an electronic device, an apparatus, and a vacuum isolation window device provided with the silicon cluster super lattice.

  In recent years, development of silicon clusters has been promoted in a broad industrial field including the semiconductor industry.

In general, a "surface electronic state" exists on the surface of a solid material, which is different from the electronic state inside the solid. In silicon crystals, a diamond structure is formed inside the crystal by the sp ³ hybrid orbital of Si atoms. Since the bonding partner of Si atoms on the crystal surface is limited to two dimensions, the crystal periodic arrangement inside the crystal is broken at the surface, and instead, the crystal surface has various crystal structures according to the crystal plane orientation of the surface (hereinafter It is also called "surface superstructure". This surface superstructure forms an electronic state unique to the crystal surface (hereinafter also referred to as "surface electronic state"), which has been studied in detail. The surface crystal structure also undergoes a structural phase transition due to the adsorption of other atoms, and the surface electronic state changes accordingly. For example, physical properties unique to the surface appear in silicon crystals, such as a large change in electron transport that defines the electrical conductivity due to adsorption of foreign elements.

  In relation to silicon clusters, the inventor of the present invention has conducted research and development so far and has reported them (see Patent Documents 1, 2, 3 and Non-patent Documents 1 and 2). For example, Patent Document 1 and Non-patent Document 1 show a method of generating silicon clusters in a gas phase by a space-time confinement method. Patent documents 2 and 3 showed about the solar cell which consists of an assembly which silicon cluster particles arranged three-dimensionally periodically. Further, Non-Patent Document 2 shows the super lattice structure of silicon clusters and the like.

Patent No. 5273495 Patent 552638 gazette International Publication 2013/027717

"Narrow size-distributed silicon cluster generated using a spatiotemporal confined cluster source", Iwata, Y .; et al. Chem. Phys. Lett. (2002) 358, 36-42. “Crystallographic Coalescence of Crystalline Silicon Clusters into Superlattice Structures”, Yasushi Iwata, Kanako Tomita, Takeyuki Uchida, and Hirofumi Matsuhata, Crystal Growth & Design (2015) 15, 2119-2128.

When considering using various surface physical properties of silicon crystal surface as semiconductor materials to meet various industrial needs in a wide range of industrial fields including the semiconductor industry, it is difficult according to the basic physical physical property principle I immediately face the challenge. In general, the physical properties of solid materials are overwhelmingly specified by the electronic state inside the solid. The surface electronic state is an electronic state formed by an atom present on the solid surface, and the number of electronic states per energy level of the electron (hereinafter, also referred to as “electron density of states. Unit [eV ⁻¹ ]) is It is proportional to the number of surface atoms. Naturally, the density of states of surface electronic states is extremely small compared to the density of electronic states in a solid, except for an extremely thin thin film material having an atomic layer number (a few nm in thickness). Therefore, the surface electronic state does not control the physical properties of the solid material, and the physical state of the solid material is defined by the electronic state inside the solid whose density of electronic states is overwhelmingly high. Furthermore, not only the electronic density of states is simply high, but in fact, the electron can be stabilized stably to take the electronic state, that is, a crystal lattice structure having periodicity to form a Bloch wave that defines the wave number of the electron. If it does not form an electronic state based on it, it does not define the physical properties of the material. For example, in the case of a porous material having a large surface area or a metal void incorporating a large number of lattice defects, an irregular surface structure such as a gap surface or the inner surface of a gap is formed inside a solid, but these surface atoms It is not specified, and the electrical properties can not be controlled by these surface structures.

  If the electron state unique to the crystal surface defines the wave number of the electron and a material that governs the physical properties is created, a highly functional, socially significant technology will be born taking advantage of the various physical properties of the crystal surface state. . For this purpose, it is required to create a surface electronic state having a stable crystal structure with high electronic state density and high periodicity.

Conventionally, when minute silicon clusters are regularly arranged on a substrate by research and development of the present inventor etc., particles do not rely on external force such as electromagnetic force by light irradiation or mechanical force by micro probe. Is known to form ordered structure (spontaneous formation of nanostructured order). Here, the following two processes have been considered as a mechanism by which micro silicon clusters spontaneously form nanostructured order. First, when cluster particles land on the crystal substrate, the particles distort the atomic arrangement on the substrate surface. When a plurality of particles are present on the substrate surface, the strained structure changes to a uniform arrangement because the crystal lattice on the substrate surface mitigates distortion of atomic arrangement as much as possible. Along with the strain relaxation of the substrate surface, the particles on the substrate are also evenly arranged to form an ordered structure. Second, the cluster particles on the substrate exchange a small amount of electrons with the substrate, and a bias of charge distribution called dipole occurs in the cluster particles. The dipoles induce weak interactions, called dispersive forces, between the cluster particles, resulting in uniform particle alignment and an ordered structure on the substrate. The former is an ordered structure in which the distance between cluster particles is relatively formed by the interaction between the substrate and the cluster particles. To date, molecular beam epitaxy has been identified in clusters formed on the substrate surface. Also, the latter forms an ordered structure by weak interaction acting between the cluster particles when they are relatively close to each other, but the clusters do not contact each other, so the electronic state of the formed ordered structure is The individual cluster particles are approximately represented by the sum of electronic states formed individually.
Furthermore, the formation of nanostructure order consisting of novel silicon clusters is desired.
Next, it demonstrates concretely.

When silicon clusters (Si _N clusters) are generated in the gas phase by the space-time confinement method (Patent Document 1, Non-patent Document 2) and a silicon cluster beam is deposited directly on a graphene substrate in vacuum, a silicon cluster superlattice is formed Be done. The crystal structure of a silicon cluster superlattice is shown in FIGS. 1 (a) and 1 (b). In silicon cluster superlattices, Si _N clusters themselves individually have a diamond crystal structure, and adjacent Si _N clusters combine with each other to form a body-centered cubic lattice structure (BCC structure) to expand three-dimensionally. A lattice structure is formed (see FIG. 1 (a)). When the crystal structure of silicon cluster superlattice is analyzed based on the crystal structure of graphene substrate using high resolution electron microscope, the diamond crystal structure possessed by Si _N cluster is the lattice constant of the diamond crystal structure formed by single crystal silicon It has a lattice constant approximately equal to a = 5.43095 Å. In the initial process of Si _N clusters forming a superlattice structure on a graphene substrate, Si _N clusters are arranged along a graphene crystal lattice to form a hexagonal close-packed structure (HCP structure) (FIG. 1 (b )reference). Si _N when it is no longer Si _N clusters in direct contact with the graphene substrate as the amount of deposition proceeds Si _N clusters deposition of clusters is increased, Si _N clusters graphene substrate uniquely stable BCC without being affected by the crystal structure of Form a superlattice structure. The lattice constant of the BCC superlattice structure is determined based on the crystal structure of the graphene substrate and is 2.134 ± 0.002 nm (see Non-Patent Document 2). The lattice constant is similarly determined for the initial HCP superlattice structure, and has the same value as the lattice constant of the BCC superlattice structure.

  In the structure of the super lattice of silicon clusters, it is desirable to realize surface electronic states having a stable crystal structure with high electronic state density and high periodicity.

  In addition, as application fields of silicon cluster superlattices, applications to semiconductor devices and other fields are desired.

  By the way, the history of the use of radiation beam (quantum beam) is extended to 160 years, and the state-of-the-art application technology of nanomaterial creation, mutation breeding, radiation beam treatment is advanced by the ionization action of electrons, protons and heavy ions There is. In the latter two fields in particular, it is necessary to take the beam into the atmosphere, and a vacuum partition thin film window (hereinafter referred to as “the beam”) that separates the vacuum for beam acceleration and transport from the atmosphere for beam irradiation and allows the transmission of quantum beams. Also called "vacuum window") technology is required. With the advancement of radiation beam technology, it is necessary for the vacuum bulkhead thin film to minimize the influence on the beam transmission. Therefore, it is required to be thin and have mechanical strength against vacuum pressure and resistance to radiation damage. In recent years, a technology that accelerates nanocluster ions composed of multiple atoms to high energy as a fourth quantum beam next to electrons, protons, and heavy ions is also attracting attention, and its overwhelmingly high ionization action is expected to become new in the future Is expected to open up new fields of radiation beam application. For the removal of high energy cluster ions into the atmosphere, a very thin thin film of less than 100 nm is required, but it has been extremely difficult for conventional thin film technology to meet the demand.

  The present invention seeks to solve these problems, and it is an object of the present invention to provide novel silicon cluster superlattices. Another object of the present invention is to provide a silicon stellar superlattice having a surface electronic state having a stable crystal structure with a high electronic state density and a high periodicity. Another object of the present invention is to provide a semiconductor device, an electronic device and an apparatus comprising the silicon cluster superlattice. Another object of the present invention is to provide a vacuum window comprising the silicon cluster superlattice.

  The present invention has the following features to achieve the above object.

The present invention relates to a silicon cluster superlattice, in which a silicon cluster having a diamond crystal structure is arranged in the shape of a body-centered cubic lattice structure having a lattice constant approximately four times the lattice constant of the silicon crystal structure. It is characterized by forming a grid.
The present invention relates to a silicon cluster superlattice, in which a silicon cluster having a diamond crystal structure is arranged in the shape of a body-centered cubic lattice structure having a lattice constant of 2.043 nm to 2.172 nm to form a three-dimensional three-dimensional lattice. It is characterized by eggplants.
In a preferred embodiment of the present invention, in the silicon cluster superlattice, surfaces of silicon clusters other than an interface formed by contacting the silicon clusters are three-dimensionally continuously connected, and a gap space surrounded by the surfaces is It is formed in the superlattice.
In a preferred embodiment of the present invention, in the silicon cluster superlattice, the number of Si atoms constituting the silicon cluster is preferably 200 or more and 256 or less.
In a preferred embodiment of the present invention, the silicon cluster superlattice preferably has a carrier conductivity, in which the number of atoms of Si constituting the silicon cluster is 200 or more and 235 or less.
A preferred embodiment of the present invention is a semiconductor device comprising the silicon cluster superlattice of the present invention as a semiconductor.
Another preferred embodiment of the present invention is an electronic device comprising the silicon cluster superlattice of the present invention as a conductor.
Another preferred embodiment of the present invention is an electronic device comprising said silicon cluster superlattice of the present invention.
Another preferred embodiment of the present invention is a device comprising a thin film consisting of said silicon cluster superlattice of the present invention.
Another preferred embodiment of the present invention is a vacuum isolation window comprising a thin film consisting of said silicon cluster superlattice of the present invention. In addition, it is preferable to provide the radiation irradiating apparatus with a vacuum isolation window including a thin film made of the silicon cluster superlattice.

It is desirable that “a lattice constant of about 4 times the lattice constant of the silicon crystal structure” be about 4-0.25 times or more and 4 + 0 times or less so as to include the case of the lattice constant of 2.043 nm in the case of Si ₂₀₂ . Furthermore, the lattice constant is preferably 3.8 times or more, and most preferably 3.9 times or more.
The lattice constant of the body-centered cubic lattice structure of the silicon cluster superlattice is desirably 2.043 nm or more and 2.172 nm or less, preferably 2.133 nm or more and 2.167 nm or less.
The number of atoms of Si constituting the silicon cluster is desirably 200 or more and 256 or less, preferably 202 or more, and most preferably 211 or more. As a specific example, the number of atoms of Si is 211 and 235.

  In the silicon cluster superlattice of the present invention, an interface in which Si atoms are covalently bonded is formed between silicon clusters in which surfaces are in contact with each other, and the diamond crystal structure inside the silicon clusters is disordered in atomic arrangement across the silicon clusters in contact. It is formed continuously. The surfaces of the silicon clusters other than the interface formed in contact with the silicon clusters are continuously connected to each other over the contacting silicon clusters, and the surfaces form a three-dimensionally mesh-like gap space in the superlattice.

  The silicon cluster superlattice of the present invention also includes those in which Si atoms of the silicon cluster are replaced with different elements. As different elements, hydrogen, oxygen, nitrogen, boron, phosphorus and the like can be mentioned. In addition, in conventional Si semiconductor materials, it can be tolerated that impurities such as metal elements which are excluded as much as possible are contained in a certain level of low level purity.

  Specifically, the vacuum isolation window can be a laminated structure of thin films consisting of at least graphene and a silicon cluster superlattice.

According to the present invention, in a silicon cluster superlattice, it is possible to realize a surface electronic state having a stable crystal structure with a high electronic state density and a high periodicity. In addition, with the Si 3 _N cluster superlattice of the present invention, it is possible to realize, for the first time, a three-dimensional surface structure that defines the physical properties of a superlattice material having a high density of electronic states. In the Si 3 _N cluster superlattice of the present invention, the three-dimensional surface structure has an infinitely extended structure with uniform crystal periodicity, so it has excellent electrical conductivity without being affected by impurities in the solid. .

By specifying the cluster size _N of silicon clusters Si _N to be in the range of 200 or more and 256 or less, the electrical conductivity varies from insulation to conductivity depending on the value of N. A silicon cluster superlattice can be realized.

  The thin film comprising the silicon cluster superlattice of the present invention has semiconductor characteristics, and a film having characteristics corresponding to p-type or n-type can be produced. A pn junction can be made of a thin film composed of a silicon cluster superlattice, which is suitable for a diode.

  The thin film comprising the silicon cluster superlattice of the present invention is extremely thin and has high strength. A layered structure in which silicon cluster superlattices are formed on graphene is suitable for a vacuum isolation window that transmits radiation.

  In the case of the nanostructured order formed on the crystal surface of the prior art and the self-ordering formation by the colloidal nanoparticles, the interaction between the nanoparticles is extremely weak, so the physical properties of the entire formed superlattice are stabilized only by the nanostructured order There is a limit in the physical principle to define in. In the silicon cluster superlattice technology of the present invention, it is possible to stably define the physical properties of the superlattice by the formation of a stable crystal structure having a high electronic density of states and high periodicity, which is successful and wide Expanded use for industrial needs.

In the Si _N cluster superlattice of the present invention, three coordinated Si atoms and four coordinated Si atoms are present on the surface, and in particular, by adsorption reaction of different elements with three coordinate Si atoms or substitution reaction with different elements Since a large change occurs in the electronic state, it is possible to form a p-type semiconductor or n-type semiconductor state of the Si 3 _N cluster superlattice by selectively adjusting the adsorption element or the substitution element. Both pn junctions form a diode, which is the basis of a semiconductor device, and an excellent semiconductor device can be realized using a surface that is rich in variations based on an energy saving Si material that is resistant to impurities.

It is a figure which shows the crystal structure of a silicon cluster superlattice, (a) is a BCC structure, (b) is a figure which shows HCP structure. It is a figure which shows the BCC superlattice structure of a Si _N cluster, (a) is a BCC superlattice structure, (b) is a figure for demonstrating the unit cell. (A) is a figure which shows the unit cell of Si ₂₁₁ cluster superlattice, (b) is a unit cell of a Si ₂₃₅ cluster superlattice. It is a figure which shows the structure of Si atom in the conventional unit cell of the BCC superlattice of a Si ₂₁₁ cluster superlattice, (b) is a figure which shows the tetrahedron surface structure which can be seen from arrow A of (a). It is a figure which shows the result of calculating _| requiring the electron density distribution along the (110) plane of a BCC super lattice structure, (a) is a Si ₂₁₁ cluster super lattice, (b) is a Si ₂₃₅ cluster super lattice, (c) is a single It is a figure about crystalline silicon. It is a figure about Si ₂₁₁ cluster super lattice, (a) is a band structure and (b) is a figure showing DOS. It is a figure about Si ₂₃₅ cluster super lattice, (a) is a band structure and (b) is a figure showing DOS. It is a figure which shows the calculation result of PDOS about Si ₂₁₁ cluster super lattice. It is a figure which shows the calculation result of PDOS about Si ₂₃₅ cluster super lattice. It is a figure which shows the result of having observed the electronic state of a Si 3 _N cluster superlattice by a high resolution electron microscope. It is a figure which shows the EELS spectrum of Si _N cluster super lattice. It is a figure which shows DOS of a single crystal silicon (c-Si), a Si ₂₃₅ cluster superlattice, and a Si ₂₁₁ cluster superlattice. It is a figure which shows DOS at the time of substituting 1 Si atom of the cluster center of Si ₂₁₁ cluster superlattice with B in 1st Embodiment. It is a figure which shows DOS at the time of substituting one 3-coordinate Si atom which is a surface atom of a Si ₂₁₁ cluster superlattice with B in 1st Embodiment. It is a figure explaining foreign element adsorption to Si ₂₁₁ cluster super lattice in a 1st embodiment, (a) is a figure explaining progress of reaction, (b) is a figure showing two kinds of reaction energy diagrams It is. It is a figure which shows the change of DOS with respect to H ₂ molecule adsorption | suction to the Si ₂₁₁ cluster super lattice surface in 1st Embodiment. It is a figure which shows the change of DOS with respect to O ₂ molecule adsorption | suction to the Si ₂₁₁ cluster super lattice surface in 1st Embodiment. It is a figure explaining the manufacturing process of the surface type diode using a Si _N cluster super lattice in a 1st embodiment. FIG. 7 is a diagram showing the structure of a vacuum window provided with a silicon cluster superlattice in the second embodiment. It is a figure which shows the structure which attaches a vacuum window to vacuum piping etc. in 2nd Embodiment. It is a figure which shows an example of a grid base in 2nd Embodiment. It is a figure which shows a mode that a silicon cluster super lattice vacuum window is attached to a grid base by laser beam welding in 2nd Embodiment.

  Embodiments of the present invention will be described below.

  In the structure of silicon cluster superlattice, the present inventor conducts research and development focusing on the electronic state of the superlattice structure by silicon cluster, and a surface electronic state having a stable crystal structure with high electronic density and high periodicity. To achieve the

  In contrast to the conventional nanostructural order, in the Si cluster superlattice of the present invention, the Si clusters are in contact with each other to form an interface, through which the uniform crystal structure is continuously connected, and the Si clusters are three-dimensionally ordered. It is a new nanostructure formation which forms a structure. The continuous connection of the uniform crystal structure to the three-dimensionally extending super lattice allows the Si cluster surface facing the gap space of the Si cluster to be continuously and uniformly continued, and the three-dimensionally expanding giant crystal surface Form The surface electronic state has the same high density of states as the inside of the cluster, and plays a large role in defining the electronic state of the Si cluster superlattice.

In the present invention, the "three-dimensional surface" formed in the super lattice structure of silicon clusters is realized for the first time. The three-dimensional surface is defined in size, and silicon clusters having an sp ³ diamond-like crystal structure are arranged in the shape of a body-centered cubic lattice structure to form a three-dimensional three-dimensional lattice, and adjacent clusters are sp ^By coalescing each other by ³ covalent bonds, the surfaces of the silicon clusters are continuously connected, and the surfaces of the silicon clusters extend sterically along the three-dimensional lattice to form a three-dimensional surface. More specifically, in the present invention, the three-dimensional surface is formed by continuously connecting the surfaces of silicon clusters in a very narrow gap formed in the silicon cluster superlattice, and the three-dimensional surface in the silicon cluster superlattice It is characterized in that the proportion occupied by the dimensional surface, that is, the proportion of the number of Si atoms forming the three-dimensional surface is large. Furthermore, by aligning silicon clusters with uniform sizes while forming superlattices and bonding them together, the cluster surface is characterized in that it forms a three-dimensional surface with periodicity over a long distance. For the first time, the three-dimensional surface of a silicon cluster superlattice has the electronic state density as high as that of the electronic state density in a crystalline solid, and the surface electronic state is the electronic properties of the silicon cluster superlattice. It became possible to become superior at In a conventional porous material known as a material in which a void is formed in a solid or a lattice defect in a crystal, the above two conditions are not met, so the surface electronic state formed in the void of the material is the material Do not control the electronic properties of

The three-dimensional surface of the silicon cluster superlattice in the embodiment of the present invention has the following characteristic properties.
(1) The electronic state density distribution of the three-dimensional surface formed in the Si ₂₁₁ cluster superlattice showing a stable structure has its center at the Fermi level, and has metallically high electrical conductivity.
(2) As the silicon cluster size increases and the gap in the superlattice decreases in the Si ₂₃₅ cluster superlattice, the intensity of the electronic state density distribution on the three-dimensional surface decreases and the center shifts to the low energy side The electrical conductivity changes to semiconducting properties. Furthermore, in the Si ₂₅₆ cluster superlattice in which the cluster size is increased, the gap in the superlattice disappears, the structure becomes equivalent to single crystal silicon, and the three-dimensional surface also disappears. Electrical conductivity exhibits the same insulator as true semiconductor silicon.
(3) The three-dimensional surface formed on the Si ₂₁₁ cluster superlattice exhibiting a stable structure has almost no effect on the density of electronic states even if an impurity is introduced into the Si ₂₁₁ cluster.
(4) Dissociative adsorption of oxygen molecules on the three-dimensional surface formed on the Si ₂₁₁ silicon cluster superlattice reacts with Si atoms on the three-dimensional surface to form Si ₂₁₁ O _x , enabling electrical conductivity control Do.

  Details will be described below.

In order to clarify the electronic states of silicon cluster superlattices by first-principles calculations, it is necessary to accurately determine the size N of Si _N clusters constituting stable silicon cluster superlattices, and stable silicon cluster superlattice structures Was determined by ab initio calculation.

In order to derive a silicon cluster superlattice that may actually exist from ab initio calculation, it is important to set initial conditions, and in this calculation, based on the experimentally determined crystal structure data of silicon cluster superlattice I proceeded with the calculation. Based on the experimental results that the crystal structure of the Si 3 _N cluster is the same as the diamond crystal structure formed by single crystal silicon, the Si 3 _N cluster was placed on a computer by cutting out from single crystal silicon at a radius R. This will be described below with reference to FIGS. 2 (a) and 2 (b). Next, experiments are performed as initial conditions of unit cells of BCC superlattice structure formed by Si _N clusters (hereinafter "unit cells" means "conventional unit cells" (two Si _N clusters are present per unit cell)). Structural BCC structure lattice constant 2.134 ± 0.002 nm of the silicon cluster superlattice is a value close to four times 2.172 nm of the diamond crystal structure lattice constant a of single crystal silicon. Introduce t ₁ (-2a, 2a, 2a), t ₂ (2a, -2a, 2a), t ₃ (2a, 2a, -2a) as translational vectors defining unit cells, and set their lattice constants to 4a and (See FIG. 2 (a)). The center of the sphere of radius R where the Si 3 _N cluster is cut out of single crystal silicon at the center and eight vertices of the BCC superlattice unit cell occupies the position (see FIG. 2 (b)). The arrangement of two Si _N cluster crystal structures can be considered with respect to the center of the sphere. One is that the Si atom is located at the center of the sphere, and the other is that the bonding center between the Si atoms is located at the center of the sphere. The size of the Si _N clusters are divided by a respective arrangement, Si _N cluster size N = 187,211,235 for Si atomic centers arrangement, calculations Si _N cluster size N = 130,166,190,202 in binding centering Subject to Table 1 summarizes the results of ab initio calculations performed using OpenMX code on the BCC superlattice structure formed by Si _N clusters of uniform size.

As shown in Table 1, in the case of the Si ₂₁₁ cluster and the Si ₂₃₅ cluster, values close to the lattice constant of 2.134 ± 0.002 nm of the BCC superlattice structure determined from the experiment were obtained. From this result, it is concluded that silicon cluster superlattices that can actually exist in a stable manner are clusters in which uniform sized Si ₂₁₁ clusters or Si ₂₃₅ clusters are most adjacent to form a BCC superlattice structure. Be At other cluster sizes, particularly in the case of bonding centered Si _N clusters, results are significantly different from the experimental values. It is difficult to keep the spherical structure stable in small sizes of Si ₁₃₀ , Si ₁₆₆ and Si ₁₈₇ , and in relatively large sizes of Si ₁₉₀ and Si ₂₀₂ , the clusters strongly bond with each other, resulting in a small lattice constant. became.

The unit cells of the Si ₂₁₁ cluster superlattice and the Si ₂₃₅ cluster superlattice are respectively shown in FIGS. 3 (a) and (b). In each superlattice unit cell, and union eight one Si _N clusters and each vertex Si _N clusters centered at of unit cell heart that is the closest in contact with cluster surface of each other, forming a superlattice structure Do. It can be seen from the calculation result that the lattice constant is almost equal in two types of superlattice unit cells of N = 211 and 235 sizes, and as the cluster size is larger, the contact area between clusters is expanded and fused. On the other hand, the area of the cluster surface exposed to the space without contact is reduced.

FIGS. 4A and 4B show the structure of Si atoms in the unit cell of the BCC superlattice of the Si ₂₁₁ cluster superlattice. The Si ₂₁₁ cluster superlattice unit cell, and eight Si _N clusters of surfaces located on the surface with the unit胞頂point of Si _N clusters unit cell center is contiguous smoothly, cooperate to (collectively) one tetrahedron surface The structure is formed (see FIG. 4 (a)). In FIG. 4 (a), (1) shows a unit cell of the BCC superlattice, (2) shows a tetrahedral surface structure formed by 240 surface Si atoms in the superlattice unit cell, FIG. 4 (b) ) Shows the tetrahedral surface structure visible from the arrow A of 4 (a). In the unit cell there are 422 Si atoms, of which 240 surface Si atoms form this surface structure. Of the 240 surface Si atoms, 216 have 1 Si atom bonded to the surrounding 3 Si atoms with 4 bond hands, leaving dangling bonds in the vertical direction on one surface The remaining 24 atoms are tri-coordinate atoms, and the orbit of the Si atom is in the surface plane and bonds to the surrounding 3 Si atoms.
In the Si ₂₃₅ cluster superlattice unit cell, 470 Si atoms exist in the unit cell, and the 312 Si atoms constituting the cluster surface among them form a surface structure exposed to a plurality of closed spaces.

On the other hand, Si atoms present inside the Si _N cluster form a sp ³ structure, and in both the Si ₂₁₁ cluster superlattice and the Si ₂₃₅ cluster superlattice, a uniform sp ³ structure is connected through the interface where the Si _N clusters contact each other. The results of determining the electron density distribution along the (110) plane of the BCC superlattice structure are shown in FIGS. 5 (a), (b) and (c). The Si ₂₁₁ cluster superlattice (FIG. 5 (a)) and the Si ₂₃₅ cluster superlattice (FIG. 5 (b)) both closely resemble the electron density distribution of single crystal silicon (c-Si, FIG. 5 (c)) It shows the distribution. It electron density distribution is uniform throughout the Si _N clusters are in contact with each other interfaces, rather than Bloch wave number of sp ³ structure Si _N cluster is formed is defined independently for each Si _N clusters, BCC superlattice structure It shows spreading uniformly throughout. That is, in the silicon cluster superlattice as shown in silicon (5) (a) (b), Si atoms present inside the Si _N cluster form an sp ³ structure uniformly regardless of the cluster size, and BCC The Bloch wave number spreads throughout the superlattice structure to form stable electronic states.

The band structures of the Si ₂₁₁ cluster superlattice and the Si ₂₃₅ cluster superlattice were calculated, and the results are shown in FIGS. 6 (a) and 7 (a). The energy states of those band structures are represented by a Gaussian function with a half width of 0.05 eV, and the number of energy states is integrated for each unit energy to obtain the density of states (hereinafter also referred to as “DOS”. Unit [eV ^{− 1} ] is shown in FIG. 6 (b) and FIG. 7 (b), respectively. In the Si ₂₁₁ cluster superlattice, a large peak appears widely near the Fermi level of DOS, and energies of 0.04 eV (E = −0.68 eV) and 0.26 eV (E = 0.27 eV) appear on both sides of the peak. There is a gap.

We calculated PDOS (projected density of states) to find out the origin of high intensity peaks near the Fermi level. The results are shown in FIG. The Si atom having the same symmetry of the crystal structure gives one PDOS, and the Si ₂₁₁ cluster gives 18 types of PDOS due to its crystal structure symmetry. Among the 18 PDOSs, mainly three types of PDOS ((1), (2), (3)) form high-intensity peaks near the Fermi level in DOS. Of these three types (1), PDOS forms 12 tricoordinated surface atoms, and PDOS of (2) and (3) is a tricoordinated surface atom among 108 tetracoordinated surface atoms. 24 pieces occupy the near position, respectively. That is, it is revealed that the high intensity peak near the Fermi level is due to the surface structure formed in the Si ₂₁₁ cluster superlattice, and that the surface electronic state forms a stable high density DOS. The Since the surface electron state indicates that DOS is as high as that of the sp ³ structure in the cluster, a surface electronic state having a stable crystal structure with high electronic state density and high periodicity is formed in the Si ₂₁₁ cluster superlattice Conclude that

On the other hand, the energy gap of 0.23 eV (E = 0.14 eV) occurs in the result of similarly obtaining DOS for the Si ₂₃₅ cluster super lattice (FIG. 7 (b)), and the energy gap is in the energy region below the Fermi level not exist. The energy distribution shape of this DOS is similar to that of P-type single crystal silicon. PDOS calculations were performed to clarify the identity of the peaks found near the Fermi level. For the Si ₂₃₅ cluster, 38 types of PDOS are required, and the results are shown in FIG. The three-coordinate atom PDOS (4) that forms the inner surface structure forms a peak seen near the Fermi level.

High-resolution transmission electron microscopy (Titan, FEI) is used to determine whether a surface electronic state with a stable crystal structure with a high electronic state density and high periodicity is formed in an actual Si _N cluster superlattice Energy loss spectroscopy (EELS) experiments were performed to investigate the electronic states of Si _N cluster superlattices. The incident energy of the electron beam was 60 keV, and the observation was performed by the EELS imaging method. The results are shown in FIG. In single crystal silicon, the L _2,3 core-loss end appearing at a loss energy of 99.8 eV is well known and corresponds to the lower end energy level of the conduction band of single crystal silicon. The L _2,3 core-loss spectrum of Si _N cluster superlattice is observed in the energy region lower than 99.8 eV which is not seen in the L _2,3 core-loss spectrum of single crystal silicon, and the conduction band of single crystal silicon It is suggested that the surface electronic level of the Si ₂₁₁ cluster superlattice appears in the energy region corresponding to the energy below the lower end, that is, the energy level in the band gap, which corresponds to the calculation result of DOS.

In order to perform theoretical calculation of energy density of states of Si _N cluster superlattice and comparison with EELS spectrum data, computer simulation of EELS spectrum of Si _N cluster superlattice was performed using QMAS code. The results are shown in FIG. L _2,3 core-loss spectrum in the energy region even lower than 99.8 eV as the number of states of single-crystal silicon (c-Si), Si ₂₃₅ cluster superlattice, Si ₂₁₁ cluster superlattice and surface electronic states increases It reproduces the situation that becomes stronger.

From the above results, the existence of surface electronic states specific to Si _N cluster superlattices revealed by theoretical calculations is experimentally confirmed, and thus, stable and excellent in periodicity in Si _N cluster superlattices It is concluded that a high density of states three-dimensional surface electronic state with crystalline structure is formed.

FIG. 12 shows DOS of single crystal silicon (c-Si), Si ₂₃₅ cluster superlattice, and Si ₂₁₁ cluster superlattice. In FIG. 12, the surface electronic state unique to the Si 3 _N cluster superlattice forms a stable DOS peak near the Fermi level, which varies greatly depending on the size of the Si 3 _N cluster. This result is satisfied when two conditions are met. First, as a first condition, in the process of Si _N cluster superlattice is formed from Si _N clusters, Si _N clusters each other by fusion, a superlattice succession sp ³ crystal structure of Si atoms through its bonding surface smoothly formed Do. This point is important because it is difficult to form a surface structure having a stable crystal structure over the entire Si _N cluster superlattice, if a discontinuous Si atomic arrangement occurs at the interface between clusters. As the second condition, even if the cluster size is increased to N = 211, 235, 256 (N = 256 is a size corresponding to single crystal silicon in the superlattice unit cell lattice constant 4a), the lattice of the BCC superlattice structure The constant is almost constant. In the theoretical model, if it is simply cut from single crystal silicon with a sphere of radius R to form Si _N clusters, if the sphere of radius R is simply a rigid body, the lattice of the superlattice unit cell as the size increases It is assumed that the constant becomes longer and the surface area of the Si 3 _N cluster superlattice also increases. However, the formation of actual Si _N cluster superlattices is not so, and as the Si _N cluster size increases, the bonding surface increases, and the bonding between Si _N clusters becomes stronger, resulting in the superlattice unit cell The lattice constant remains approximately constant without change. In connection with the lattice constant being approximately equal to 4a, it can be inferred that there exists a stable structure of a superlattice structure inherent to the crystal structure (diamond structure) by the sp ³ orbital formed by four coordinate Si atoms. In any case, in a superlattice unit cell maintaining a constant lattice constant close to 4a as the Si 3 _N cluster size increases, the area of the surface structure of the Si 3 _N cluster superlattice decreases in reverse. The surface states of the Si ₂₁₁ cluster superlattice shown in FIG. 12 form large DOS on the Fermi level, which indicates that this surface electronic state is metallic which is easy to transport electrons. This is because the surface structure of the Si ₂₁₁ cluster superlattice smoothly connects the surface of the Si _N cluster to form a macrostructure which extends throughout the superlattice. In the Si ₂₃₅ cluster superlattice, as the fusion between Si _N clusters proceeds, the surface is cut to form some closed spaces (lattice defects) in the superlattice unit cell, and the local remains in the superlattice unit cell Surface structure is formed. As a result, the surface state of the Si ₂₃₅ cluster superlattice shown in FIG. 12 is semiconductive (p-type Si). Furthermore, as the Si 3 _N cluster size increases, the gap also disappears, and an electrical insulation state of single crystal silicon, that is, an authentic semiconductor is obtained.

First Embodiment
In the present embodiment, a semiconductor device using the surface electronic state of the silicon cluster superlattice of the present invention will be described below with reference to FIGS.

First, a diode as a basic device will be described as an electronic device utilizing the surface electronic state of a silicon cluster superlattice. The diode is obtained by joining two kinds of semiconductors different in Fermi level. In the case of single crystal silicon, Fermi level control forms a p-type semiconductor by doping with a group III element including B. Figures 13 and 14 show DOS analysis results when one Si atom of 211 Sis constituting two Si ₂₁₁ clusters contained in BCC superlattice unit cell of Si ₂₁₁ cluster superlattice is replaced with B respectively. Shown in. When substitution occurs at the center of the Si ₂₁₁ cluster (FIG. 13), a band gap is formed in the upper and lower energy regions of the surface electronic states that show a strong peak on the Fermi level when compared to DOS before substitution No major difference is seen in the electronic state. On the other hand, when the three-coordinate Si atom of the surface atom is substituted (FIG. 14), a new minute peak is formed in the band gap of the upper energy region of the surface electronic state as compared with DOS before substitution. In the figure, the corresponding area is indicated by diagonal lines. This result indicates that the band structure control of the surface electronic state is possible by the substitution reaction of the surface three coordinating atoms with the foreign element.

In order to evaluate the substitution position of the surface Si atom in more detail, substitution with H is analyzed as an example. Of the 240 surface Si atoms in the BCC superlattice unit cell of the Si ₂₁₁ cluster superlattice, 24 (12 per Si ₂₁₁ cluster) are three-coordinate Si atoms. The three-coordinate Si atoms are Si atoms arranged so as to face each two in six spaces formed in the xy-z-axis direction of the three-dimensional periphery of the Si 3 _N cluster. FIGS. 15 (a) and 15 (b) show the progress of the adsorption reaction of the different element (example H ₂ ) on the Si ₂₁₁ cluster superlattice. When hydrogen molecules (H ₂ ) are introduced into the space where three three-coordinate Si atoms face each other in six spaces, there is no energy barrier and they are dissociated and adsorbed with two three-coordinate Si atoms. A reaction occurs. FIG. 15 (b) shows two types of reaction energy diagrams depending on the adsorption position in the adsorption reaction of H ₂ molecules of the surface atoms. The reaction proceeds according to a deep potential diagram while the adsorption reaction with the three-coordinate Si atom proceeds, while the hydrogen molecule does not dissociate to surface atoms other than the three-coordinate Si atom, and the bond of weak dispersion force Will occur. Analysis of H ₂ molecules adsorption on Si ₂₁₁ cluster superlattice surfaces, the different element adsorption reaction to Si ₂₁₁ cluster superlattice surface revealed that the adsorption reaction is identified surface atom positions which proceeds with stable The The change in DOS for H ₂ molecule adsorption on the Si ₂₁₁ cluster superlattice surface is shown in FIG. The surface adsorption of B shown in FIG. 14 represents the result of replacing one of the 12 tricoordinate Si atoms present in the Si ₂₁₁ cluster with B. Examination of the band structure corresponding to the small peak of DOS formed in the upper energy direction of the surface electronic state by B substitution reveals that a new band structure is formed immediately below the lower end of the conduction band.

While in B substituted with Si ₂₁₁ clusters inside the Si atom, as shown in FIG. 13, the surface electron states of Si ₂₁₁ cluster superlattice hardly affected. When two B atoms are present in the BCC superlattice unit cell, the B concentration is 2.03 × 10 ²⁰ cm ⁻³ , which corresponds to extremely high concentration B doping. Nevertheless, the surface electronic states formed in the Si ₂₁₁ cluster superlattice are largely unaffected. This result can be analogized not only to B substitution but also to impurities such as other foreign elements and metals. That is, it is shown that the surface electronic state formed in the Si ₂₁₁ cluster superlattice is also insusceptible to impurities. Today, silicon, which is a major semiconductor material, is strictly defined according to applications such as solar grade for solar cells (7N-9N) and semiconductor grade for integrated circuits (SEG-Si: 11N), and it consumes a large amount of power. It is synthesized. With high integration of semiconductors approaching the limit, purification of large diameter substrates is becoming increasingly difficult even in Si material synthesis. On the other hand, in diode-based electronic devices that use the surface electronic state of Si _N cluster superlattice, high functionality is achieved by using inexpensive solar grade silicon materials instead of high purity semiconductor materials such as SEG-Si. Enable the creation of semiconductor devices with

Next, with respect to the case where O ₂ molecules are introduced into the Si ₂₁₁ cluster superlattice, the dissociation reaction of the O ₂ molecules is subsequently examined. One O ₂ molecule is sequentially introduced one by one into six spaces formed around two Si ₂₁₁ clusters in a BCC superlattice unit cell, and two three-coordinate Si atoms facing each space The results of analyzing the DOS change by dissociation and adsorption are shown in FIG. FIG. 17 shows DOS for Si ₂₁₁ , Si ₂₁₁ O ₂ , Si ₂₁₁ O ₄ and Si ₂₁₁ O ₁₂ . As the amount of adsorbed O ₂ molecules increases, the peak position of the surface electronic state shifts downward to the Fermi level. In Si ₂₁₁ O ₁₂ in which all three coordinated Si atoms are adsorbed with O atoms, the band gap on the low energy side of the surface electronic state disappears. Looking at the band structure in this state, a surface state is formed immediately above the valence band, indicating the possibility of forming a p-type semiconductor close to the band structure of p-type single crystal Si.

Further, in order to explain the n-type semiconductor of the Si ₂₁₁ cluster superlattice, it will be explained by returning to FIG. 14 again. The small peak of DOS that appears by replacing one of the three-coordinate Si atoms present on the surface of the Si ₂₁₁ cluster superlattice with B indicates that a new band structure is formed immediately below the lower end of the conduction band. In that respect, it is similar to the band structure of n-type single crystal Si. However, this electronic state is metallic because there is a Fermi level near the center of the main peak of DOS that indicates the surface electronic state. From this state, O ₂ molecules are sequentially introduced one by one into six spaces formed around the Si ₂₁₁ cluster, and dissociated and adsorbed with three-coordinate Si atoms, as shown in FIG. The peak position of the electronic state shifts downward to the Fermi level. As a result, a new band structure is formed immediately below the lower end of the conduction band, and a band gap is opened above the Fermi level. This band structure indicates the possibility of forming an n-type semiconductor close to the band structure of n-type single crystal Si.

The surface electronic state is controlled by adsorbing different elements to the three-coordinate Si atoms present on the surface of the Si ₂₁₁ cluster superlattice or replacing them with other elements, thereby controlling the n-type semiconductor of the Si ₂₁₁ cluster superlattice and p. It shows the possibility of forming two kinds of electronic states of semiconductors. By joining these two types of Si ₂₁₁ cluster superlattice semiconductors, it is possible to form a superlattice surface diode having a rectifying function, and an example of its structure will be described. FIG. 18 shows a structure of a superlattice surface diode and a method of forming the same. A Si cluster beam is vapor-deposited on the substrate 5 to which a metal electrode (aluminum electrode) is attached to form a Si cluster super lattice 1 (see FIG. 18a). Next, O ₂ is introduced into a vacuum vessel to carry out dissociative adsorption of O atoms on the surface of the Si cluster super lattice, thereby forming a Si cluster super lattice p-type semiconductor 2 (see FIG. 18 b). B atoms are introduced into the Si cluster p-type superlattice semiconductor 2 using, for example, a plasma sputtering method (B atom introduction 3) to form a Si cluster superlattice n-type semiconductor 4 (see FIG. 18c). Finally, a metal electrode (silver electrode) 6 is attached to form a structure of a Si cluster super lattice surface diode (see FIG. 18 d).

Second Embodiment
In the present embodiment, a vacuum isolation thin film window will be described below with reference to FIGS. 19 to 22 as an example of a device using a silicon cluster super lattice of the present invention.

  FIG. 19 shows the structure of a vacuum window provided with a silicon cluster superlattice. The vacuum window consists of a laminated structure in the order of metal grid 11, microgrid 12, graphene 13 and silicon cluster super lattice from the vacuum side, and a sample 16 such as a microorganism is placed on the air side of silicon cluster super lattice 14. . In the vacuum window, a microgrid 12 in which a Colaose (cellulose acetobutylate) deposited on a metal grid 11 is deposited forms a basic framework supporting a thin film (graphene 13 and silicon cluster superlattice 14). Sheets of graphene 13 are laid down until the openings are covered by microgrids 12 with an opening diameter of several μm to form an ultrathin substrate for producing silicon cluster superlattices 14. Silicon cluster beams generated by space-time confined cluster source were directly deposited on graphene sheet substrate in ultra high vacuum to fabricate silicon cluster super lattice vacuum window.

  FIG. 20 shows a structure for attaching the vacuum window 20 to a vacuum pipe provided with a structure for passing the radiation beam 15 for vacuum isolation between the vacuum side and the atmosphere side.

The produced vacuum window will be specifically described. For the metal grid 11, a platinum mesh (200 mesh) with a diameter of 3 mm and a thickness of 10 μm was used. In order to attach a metal flange for vacuum sealing, a gasket for vacuum piping (sus316L) was processed to produce a grid pedestal. FIG. 21 shows an example of the grid pedestal. The grid pedestal was fabricated with three types of aperture diameters D = 1.0 mm, 1.5 mm and 2.0 mm at the center for beam passage. Further, in order to perform laser welding with the metal grid 11 well, a counterbore having a depth of 0.03 mm was processed on the grid pedestal. A silicon cluster superlattice vacuum window was attached to the grid pedestal by laser beam welding. FIG. 22 illustrates an example of laser beam welding. A vacuum dividing wall is formed on the vacuum piping by sandwiching the grid pedestal surface with the vacuum piping sealing edge surface and vacuum sealing (see FIG. 19). The pressure applied under vacuum on a 200 mesh platinum mesh used as a metal grid is 144 mg per 1.44 × 10 ⁻⁴ cm ² of grid opening 0.12 mm × 0.12 mm. Further, a microgrid 12 with an opening diameter of several μm is stretched at the opening of the metal grid 11. The graphene of several tens of μm or more was formed so that the openings of the microgrid having an opening diameter of several μm were sufficiently covered by the graphene. Raw materials used natural graphite (SNO-30, SEC Carbon Co., Ltd.). The Hummer's solution used in the graphite oxidation step was used at a molar ratio to SNO-30 about 2.5 times more than the ratio normally used. The mixed amount of Hummer's solution is concentrated sulfuric acid (H ₂ SO ₄ , 0.617 mol), potassium permanganate (KMnO ₄ , 0.0277 mol) with respect to 0.398 g (0.033 mol) of the input amount of SNO-30. ), Sodium nitrate (NaHO ₃ , 0.00874 mol). The oxidation step was carried out over 120 hours, during which the average solution temperature was 32.5 ° C. The progress of oxidation was monitored by light microscopy. After the oxidation has sufficiently proceeded, the oxidized nanocarbon solution is transferred to a 5% dilute aqueous sulfuric acid solution for dilution, and then it is reduced with hydrogen peroxide to stop the oxidation reaction. After sufficient purification with a 3% dilute aqueous sulfuric acid solution, purification is continued with ultrapure water, and finally, a diluted solution of graphene dispersed in isopropyl alcohol is dropped onto a microgrid. The percentage of graphene coating in the microgrid is observed with an electron microscope. The graphene coverage was adjusted based on the electron microscope data. The graphene preferably has a thickness of less than 1 nm.

A silicon cluster beam generated by a space-time confined cluster source was directly vapor-deposited on a graphene sheet substrate in ultra-high vacuum on the prepared graphene sheet to form a silicon cluster super lattice film. A method of controlling the size and generating a Si _N cluster beam to form a Si _N cluster superlattice is described. He fluid is introduced into a cell of spheroid shape with a long diameter of 100 mm cooled to liquid nitrogen temperature, and a single crystal Si target is irradiated with Nd: YAG laser. When the center of the 4 mm diameter irradiation spot of the Si target sample is aligned with the elliptical focal point and the target sample surface is set perpendicular to the elliptical axis, the Si vapor ejected from the Si target sample travels along the elliptical axis and on the elliptical axis The He fluid is pushed back in front of the cell with a diameter of 3.6 mm provided at the other inner wall end, and the tip of Si vapor stagnates for a while near the outlet. At the interface between Si vapor and He fluid, a mixed region layer of both gases is formed, and only in this mixed region layer, Si _N clusters are generated. The temperature of the Si vapor ejected by laser evaporation is several thousand ° C, while the He fluid is sufficiently cooled to the liquid nitrogen temperature (-196 ° C) by the reservoir provided just before introduction into the cell in vacuum, and then to the same temperature. Since it is introduced into the cooled cell, agglomeration of Si vapor by rapid cooling proceeds in the mixed region layer of both. In the vicinity of the tip of Si vapor, intense particle collision occurs, and Si atoms are excited to emit light. The thickness of the mixed region layer is found by observing the light emission image with a high-speed framing camera and analyzing the rise of the light emission intensity at the tip of the Si vapor, the thickness is about 1 mm or less, and spreads over time Even if it does not greatly exceed 1 mm, it indicates that this mixed area is confined to a very local space area. The time for the Si vapor to diffuse over a distance of 1 mm or less in the mixed region is about 1 ms. For this time, from the decay time of luminescence intensity showing the time when intense particle collision of the aggregation process of Si vapor occurs, the time for which this mixed region layer is continued is 20-30 μs in half life, and 100 μs in 4σ decay as well. There is no. From the above analysis, the time when the mixed area layer is confined in the local space is sufficiently short with respect to the diffusion time, and the mixed area layer continues for a fixed time without causing a large shape change, and then rotates along the He fluid flow From the outlet of the elliptical cell it flows into the vacuum. The laser irradiation cycle is 20 Hz, and the amount of Si evaporation per pulse is 2.7 × 10 ¹⁶ Si atoms. In the mixed region layer with high-density low-temperature He fluid, heat of aggregation is rapidly taken away by repeating collisions with He frequently simultaneously with collisions of Si atoms, and only neighboring Si atoms always collide with each other. A condition is established in which a process of aggregation (cogulation model, in which clusters grow with N = 2 ^s with respect to the number of collisions s) tends to occur. The initial cluster growth rate is high, and the growth rate rapidly decreases as the growth progresses, and cluster growth converges to a constant size in a fixed time.

The Si _N cluster beam generated by the space-time confined cluster source is ejected from the cell into a vacuum and is deposited on the substrate under ultrahigh vacuum via a skimmer. Si _N clusters are deposited on the substrate with a high efficiency of 2% or more of the amount of Si evaporation per laser pulse. The cluster beam travels to the substrate with a short pulse of less than 100 μs, the peak value of the particle beam current reaches 2 × 10 ¹⁶ cm ^-2 s ^-1 , and the dynamic rearrangement is repeated on the substrate, resulting in a stable Si _N cluster A superlattice is formed. The silicon cluster super lattice film is preferably about 20 to 50 nm.

  By using a silicon cluster superlattice, it is possible to form an ultrathin high-strength thin film, and it is possible to take out from a vacuum where high energy cluster ions and the like are taken out to the atmosphere.

  Note that the examples shown in the above-described embodiment and the like are described to facilitate understanding of the invention, and the present invention is not limited to this embodiment.

  The silicon cluster super lattice film of the present invention can be controlled to have desired electrical characteristics, so that a conductor, a semiconductor, an insulator, etc. can be realized, and various semiconductor elements such as diodes, etc. It can be widely used for devices requiring ultra-thin high-strength thin films such as vacuum isolation windows, and is industrially useful.

1 Si _N cluster super lattice 2 p type super lattice semiconductor 3 B atom introduction 4 n type super lattice semiconductor 5 metal electrode (aluminum electrode) substrate 6 metal electrode (silver electrode)
11 metal grid 12 micro grid 13 graphene 14 silicon cluster super lattice 15 radiation beam 16 microorganism etc. sample 20 vacuum isolation window

Claims (10)

  A silicon cluster characterized in that a silicon cluster having a diamond crystal structure is arranged in the shape of a body-centered cubic lattice structure having a lattice constant approximately four times the lattice constant of the silicon crystal structure to form a three-dimensional three-dimensional lattice. Super lattice.   A silicon cluster superlattice characterized in that a silicon cluster having a diamond crystal structure is arranged in the shape of a body-centered cubic lattice structure having a lattice constant of 2.043 nm to 2.172 nm to form a three-dimensional three-dimensional lattice. .   The surfaces of the silicon clusters other than the interface formed by contacting the silicon clusters are continuously connected in a three-dimensional manner, and the gap space surrounded by the surfaces is formed in the superlattice. Or 2 silicon cluster super lattices.   The silicon cluster superlattice according to claim 1 or 2, wherein the number of atoms of Si constituting the silicon cluster is 200 or more and 256 or less.   The silicon cluster superlattice according to claim 1 or 2, wherein the number of atoms of Si constituting the silicon cluster is 200 or more and 235 or less, and the carrier conductivity is provided.   A semiconductor device comprising the silicon cluster superlattice according to any one of claims 1 to 5 as a semiconductor.   An electronic device comprising the silicon cluster superlattice according to any one of claims 1 to 5 as a conductor.   An electronic device comprising the silicon cluster superlattice according to any one of claims 1 to 5.   An apparatus comprising a thin film consisting of the silicon cluster superlattice according to any one of claims 1 to 5. A vacuum isolation window comprising a thin film consisting of a silicon cluster superlattice according to any one of claims 1 to 5.

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