Method for manufacturing a crystal

Abstract

Crystals useful for semiconductors are advantageously manufactured in industry. One manufacturing method is a method of manufacturing crystals by growing crystals through reaction of a raw material, wherein the raw material contains a substance in which germanium dioxide powder is dissolved or dispersed in water, and according to this manufacturing method, crystals, for example, for semiconductor devices (for example, compound semiconductor electronic devices and the like), electronic components and electrical equipment components, optical and electrophotographic-related devices, industrial members, and the like, are manufactured.

Description

Technical Field

[0001] This invention relates to a method for manufacturing germanium dioxide crystals. Background Technology

[0002] In recent years, rutile-structured germanium dioxide (r-GeO2) has attracted attention as a promising ultra-wide bandgap (UWBG) semiconductor for future power electronic devices. With a bandgap of 4.68 eV, r-GeO2 can be used to realize both n-type and p-type semiconductors and can be fabricated inexpensively, thus it is expected to be a next-generation semiconductor device.

[0003] In Non-Patent Document 1, Patent Document 1, Patent Document 2, and Patent Document 3, a laminated structure in which an r-GeO2 crystalline film is stacked on an r-TiO2 (001) substrate was studied. However, regarding Non-Patent Document 1, after review of Non-Patent Document 1, an errata Non-Patent Document 2 was proposed (Non-Patent Document 2). The grains (abnormal grains) described in Non-Patent Document 1 and Patent Document 1 were identified as rutile germanium dioxide crystals, with the remaining portion being an amorphous phase. That is, only the majority of the grains are amorphous, and even when crystalline phases are formed, the grains are only partially formed. Therefore, a solution is desired that can manufacture a crystalline film with excellent crystallinity that can be electrically controlled.

[0004] Furthermore, Non-Patent Literature 3 investigated the fabrication of an r-(Ge,Sn)O2 alloy thin film by mixing easily crystallizable tin dioxide with r-GeO2, confirming n-type conductivity. However, because the band gap of r-SnO2 is 3.7 eV, which is smaller than that of r-GeO2, the characteristics of r-GeO2 cannot be fully utilized in the r-(Ge,Sn)O2 alloy thin film. Additionally, controlling the composition of Ge and Sn is difficult, thus hindering the control of electrical properties. Therefore, a method is desired that allows conductivity to be obtained from a single phase of r-GeO2 thin film.

[0005] Existing technical documents

[0006] Non-patent literature

[0007] Non-patent document 1: H.Takane, K. Kaneko., "Establishment of a growth route ofcrystallized rutile GeO2 thin film (≥1 μm / h) and its structural properties", Applied Physics Letters Vol.119, pp.062104 (1-6) (2021).

[0008] Non-patent document 2: H.Takane, K. Kaneko., Erratum: "Establishment of a growthroute of crystallized rutile GeO2 thin film (≥1 μm / h) and its structural properties", Applied Physics Letters Vol.120, 099903 (1-3) (2022).

[0009] Non-patent literature 3: H. Takane, et al., “Band-gap engineering of rutile-structured SnO2-GeO2-SiO2 alloy system”, PHYSICAL REVIEW MATERIALS 6, 084604 (2022).

[0010] Patent documents

[0011] Patent Document 1: International Publication No. 2023 / 008452

[0012] Patent Document 2: International Publication No. 2023 / 008453

[0013] Patent Document 3: International Publication No. 2023 / 008454 Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] The object of this invention is to provide an industrially advantageous method for manufacturing crystals useful for semiconductors.

[0016] Problem-solving methods

[0017] To achieve the above-mentioned objectives, the inventors have conducted intensive research and have discovered a manufacturing method characterized by growing crystals by thermally reacting raw materials to produce a crystalline film. The raw materials include a substance formed by dissolving or dispersing germanium dioxide powder in water. This manufacturing method can easily and cost-effectively produce a crystalline film with GeO2 as the main component on the entire surface of a crystal substrate. The resulting crystalline film has excellent crystallinity and excellent electrical properties, and is useful in semiconductor devices and the like. Furthermore, it has been found that such a crystalline film can solve the aforementioned existing problems in one fell swoop.

[0018] Furthermore, after obtaining the above insights, the inventors conducted further reverse research until the present invention was completed.

[0019] That is, the present invention relates to the following invention.

[0020] [1] A manufacturing method characterized in that it is a method of manufacturing crystal by causing raw materials to react and grow crystals, wherein the raw materials include a substance formed by dissolving or dispersing germanium dioxide powder in water.

[0021] [2] According to the manufacturing method described in [1] above, the raw material further comprises acid.

[0022] [3] According to the manufacturing method described in [1] above, wherein the acid contains elements of group 17 of the periodic table.

[0023] [4] According to the manufacturing method described in [1] above, the crystal structure of the germanium dioxide powder includes hexagonal crystal or amorphous phase.

[0024] [5] The manufacturing method described in [1] above further includes a step of atomizing or dropletizing the raw material.

[0025] [6] The manufacturing method described in [5] above includes a step of conveying the raw material that has been atomized or dropletized by gas.

[0026] [7] The manufacturing method described in [1] above, wherein the reaction is carried out in an oxygen atmosphere or an inactive atmosphere.

[0027] [8] According to the manufacturing method described in [1] above, wherein the reaction is a thermal reaction carried out at a temperature above 500°C and below 1000°C.

[0028] [9] The manufacturing method described in [1] above, wherein the crystal growth is performed on a substrate.

[0029]

[10] According to the manufacturing method described in [9] above, the substrate is a crystal substrate.

[0030]

[11] According to the manufacturing method described in

[10] above, the crystal substrate has a rutile structure.

[0031]

[12] A manufacturing method characterized in that it is a method of manufacturing an epitaxial wafer by causing a raw material to react on a crystal substrate to grow a crystalline film, wherein the raw material comprises a substance formed by dissolving or dispersing germanium dioxide powder in water.

[0032]

[13] According to the manufacturing method described in

[12] above, the crystal substrate has a rutile structure.

[0033]

[14] According to the manufacturing method described in

[12] above, wherein the raw material contains a dopant.

[0034]

[15] According to the manufacturing method described in

[12] above, the dopant contains at least one element of Group 13 or Group 15 of the periodic table.

[0035] The effects of the invention

[0036] The manufacturing method of the present invention can be industrially advantageously used to manufacture crystals useful for semiconductors. Attached Figure Description

[0037] Figure 1 This is an example of a schematic structural diagram of a film-forming apparatus preferred for use in this invention.

[0038] Figure 2 This is a schematic diagram illustrating an atomizing device preferably used in this invention.

[0039] Figure 3 This is a graph showing the 2θ / ω result in the XRD diffraction results of Example 1.

[0040] Figure 4 This is a graph of the ω scan results from the XRD diffraction results of Example 1.

[0041] Figure 5 This is a diagram showing the AFM image of Example 1.

[0042] Figure 6 This is a diagram showing the SEM image of Example 1.

[0043] Figure 7 This is a diagram showing the EDS image of Example 1.

[0044] Figure 8 This is a graph showing the 2θ / ω result in the XRD diffraction results of Example 2.

[0045] Figure 9 This is a graph showing the ω scan results in the XRD diffraction results of Example 2.

[0046] Figure 10 This is a graph showing the 2θ / ω result in the XRD diffraction results of Example 3.

[0047] Figure 11 This is a graph showing the ω scan results in the XRD diffraction results of Example 3.

[0048] Figure 12 This is a schematic diagram of a sample on which an ohmic electrode is formed on the crystalline film of Example 2.

[0049] Figure 13 It shows the use Figure 12 A graph showing the results of the ohm measurement.

[0050] Figure 14 This is a schematic cross-sectional view of the atomizing device preferably used in this invention, viewed from the side.

[0051] Figure 15 This is a graph showing the SIMS measurement results of the test example.

[0052] Figure 16 This is a schematic diagram of a sample on which an ohmic electrode is formed on the crystalline film of Example 3.

[0053] Figure 17 It shows the use Figure 16 A graph showing the ohm measurement results. Detailed Implementation

[0054] The manufacturing method of the present invention is characterized in that it is a method of producing a crystalline film by causing a thermal reaction of raw materials to grow crystals, wherein the raw materials include a substance formed by dissolving or dispersing germanium dioxide powder in water.

[0055] In addition, it is characterized by being a method for manufacturing epitaxial wafers by growing a crystalline film on a crystal substrate through reacting raw materials, wherein the raw materials include a substance formed by dissolving or dispersing germanium dioxide powder in water.

[0056] In this invention, it is preferable that the raw material further comprises an acid, and more preferably, the acid comprises an element of Group 17 of the periodic table. Examples of elements of Group 17 include fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). Furthermore, the raw material is not particularly limited as long as it does not impair the purpose of this invention, and may comprise known solvents such as inorganic solvents like water, organic solvents such as alcohols, acid solvents, alkaline solvents, or mixtures thereof; however, in this invention, it is preferable to include an acid solvent. Examples of inorganic solvents include water, and more specifically, examples include pure water, ultrapure water, tap water, well water, mineral water, mineralized water, hot spring water, spring water, fresh water, and seawater; however, in this invention, ultrapure water is preferred. Examples of acid solvents include, for example, protic acids such as hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, nitric acid, acetic acid, carbonic acid, formic acid, benzoic acid, hydrogen peroxide, chlorite, hypochlorous acid, sulfurous acid, hyposulfuric acid, nitrous acid, hyponitric acid, phosphorous acid, and hypophosphorous acid, or mixtures thereof. Examples of alkaline solvents include, for example, sodium hydroxide, potassium hydroxide, calcium hydroxide, or mixtures thereof. Examples of organic solvents include, for example: ester solvents (e.g., ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate, butyl propionate, etc.); ether solvents (e.g., diethyl ether, tert-butyl methyl ether, diethylene glycol dimethyl ether (e.g., diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, diethylene glycol diethyl ether), 1,2-dimethoxyethane, tetrahydrofuran, etc.); amide solvents (e.g., N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolinone, etc.); ketone solvents (e.g., methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, cyclopentanone, etc.); nitrile solvents (e.g., acetonitrile, propionitrile, etc.); alcohol solvents (e.g., methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, etc.); halogenated solvents (e.g., Dichloromethane, chloroform, etc.); aromatic solvents (e.g., toluene, xylene, chlorobenzene, nitrobenzene, etc.). Based on this preferred range, it is possible to easily manufacture higher quality and larger area crystals.

[0057] Furthermore, in this invention, it is preferable to perform the crystal growth on a substrate. The substrate is not particularly limited as long as it does not impede the purpose of this invention, but it is preferably a crystal substrate. Furthermore, it is more preferable to perform the crystal growth after atomizing or dropletizing the raw material. In this invention, a step of conveying the atomized raw material by gas is preferably included. The gas is not particularly limited as long as it does not impede the purpose of this invention; for example, as preferred examples, inert gases such as air, H2O, NO, NO2, N2O, H2O, O3, O2, N2, CO2, or Ar, or reducing gases such as hydrogen or forming gases, halogen gases (e.g., fluorine, chlorine, bromine, or iodine), hydrogen halide gases (e.g., hydrofluoric acid, hydrochloric acid, hydrogen bromide, hydrogen iodide), and hydrogen are also acceptable. Based on this preferred range, higher quality crystals can be easily obtained at a lower cost.

[0058] The reaction is preferably carried out in an oxygen atmosphere or an inert atmosphere. Furthermore, the reaction is preferably a thermal reaction carried out at a temperature above 500°C and below 1000°C. Based on this preferred range, crystals with superior crystallinity can be obtained more easily.

[0059] Furthermore, the crystal substrate is not particularly limited as long as it does not impede the purpose of the present invention. It can be a known substrate, an insulating substrate, a conductive substrate, or a semiconductor substrate. It can be a single-crystal substrate or a polycrystalline substrate. The crystal substrate can also be a substrate with a metal film on its surface. The crystal substrate of the present invention preferably has a rutile structure. According to this preferred range, it is easier to manufacture a crystalline film with good crystallinity. Examples of substrates having the rutile crystal structure include, for example, a rutile GeO2 substrate, a magnesium fluoride substrate, or a rutile TiO2 substrate. Also, when the crystal substrate is a conductive substrate, it can be used for the fabrication of vertical devices without removing the substrate. The crystal structure of the crystal substrate is not particularly limited as long as it does not impede the purpose of the present invention. Examples of crystal structures for the crystal substrate include, for example, a hexagonal crystal system, a cubic crystal system, and a tetragonal crystal system. Examples of hexagonal crystal substrates include GaN substrates, SiC substrates, and sapphire substrates (a-plane sapphire, c-plane sapphire, m-plane sapphire, and r-plane sapphire substrates, etc.). Examples of tetragonal crystal substrates include GeO2 substrates with rutile crystal structures, TiO2 substrates with rutile crystal structures, and MgF2 substrates. Examples of cubic crystal substrates include Si substrates and SiC substrates. Furthermore, the crystal substrates may have an off-angle, specifically, for example, 0.1° or more and 10° or less. In this invention, the resulting stacked structure is also included. According to this preferred range, electrical properties can be further improved, better crystallinity can be achieved, and it can be more easily applied to semiconductor devices, etc. According to this preferred range, crystals with superior crystallinity can be manufactured, and manufacturing is easier.

[0060] The raw material preferably contains a dopant. Furthermore, the dopant more preferably contains at least one element from Group 13 or Group 15 of the periodic table. Examples of elements from Group 13 include boron (B), aluminum (Al), gallium (Ga), and indium (In). Examples of elements from Group 15 include nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). Based on this preferred range, crystals with better electrical properties can be produced. Based on this preferred range, crystals with superior semiconductor properties can be manufactured.

[0061] The germanium dioxide powder is not particularly limited to any type of germanium dioxide powder, but it is preferred to contain a hexagonal crystal structure and / or an amorphous phase. Furthermore, as a means of dissolving or dispersing the germanium dioxide powder in the raw material, known dissolution or dispersion methods can be listed. In this invention, ultrasonic vibration is preferred to dissolve or disperse the germanium dioxide powder in water. Based on this preferred range, it is easier to dissolve it in the water, and the raw material can be obtained more easily.

[0062] In this invention, the crystalline film can be directly formed on the crystal substrate, or a layer different from the crystalline film (e.g., an n-type semiconductor layer, n...) can be stacked on the crystal substrate. ＋ Type semiconductor layer, n － After forming other layers such as a semiconductor layer (including a semi-insulator layer), a buffer layer, etc., a film is formed on the substrate via these other layers. In particular, a buffer layer is preferably used to mitigate the lattice constant difference between the crystalline substrate and the crystalline film. Examples of materials constituting the buffer layer include SnO2, TiO2, VO2, MnO2, RuO2, CsO2, IrO2, GeO2, CuO2, PbO2, AgO2, CrO2, SiO2, SiC, GaN, Pt, and mixed crystals thereof. Also, in this specification, "film" may be replaced with "layer".

[0063] The crystal, for example, can be obtained by using... Figure 1 The film-forming apparatus shown is easier to manufacture. Furthermore, the film-forming apparatus can also be used for suitable doping. The doped crystal is suitable for use as a semiconductor film or semiconductor layer, and existing doping methods in oxide semiconductors can be applied to n-type or p-type dopants. Examples of n-type dopants include, for example, antimony (Sb), arsenic (As), bismuth (Bi), phosphorus (P), fluorine (F), niobium (Nb), vanadium (V), tantalum (Ta), or tungsten (W). Examples of p-type dopants include, for example, aluminum (Al), gallium (Ga), or indium (In).

[0064] Example

[0065] (Example 1)

[0066] Figure 1The figure shows an example of a preferred embodiment of the film-forming apparatus of the present invention. The film-forming apparatus 19 comprises: a sample 20 to be film-formed, a sample stage 21, a carrier gas source 22a, a carrier gas source 22b, a flow regulating valve 23a, a flow regulating valve 23b, a film-forming chamber 27, a heater 28, and an atomizing device 30. The atomizing device 30 comprises: a raw material partition 24, a raw material solution for atomization 24a, an ultrasonic transmission substrate 24b, a stage 24c, an ultrasonic transducer 26, a guide partition 31, an ultrasonic transmission liquid tank 35, and an ultrasonic transmission liquid 36. Furthermore, Figure 2 This figure shows an example of another preferred embodiment of the film-forming apparatus when the atomizing device of the present invention is used as a film-forming atomizing stage. The atomizing device 30 is configured as follows: a raw material partition 24, an atomizing raw material solution 24a, an ultrasonic transmission substrate 24b, a stage 24c, an ultrasonic transducer 26, a guide partition 31, an ultrasonic transmission liquid tank 35, and an ultrasonic transmission liquid 36. The sample stage 21 is made of quartz, and the surface on which the sample 20 to be film-formed is placed is inclined from the horizontal plane. By making both the film-forming chamber 27 and the sample stage 21 quartz, impurities from the device are suppressed from entering the crystalline film formed on the sample 20 to be film-formed. The atomizing raw material solution 24a is contained within the raw material partition 24. The guide partition 31 is in contact with the ultrasonic transmission substrate 24b. Figure 14 This is a schematic cross-sectional view of the atomizing device used in this invention, taken from the side. Figure 14 The atomizing device 30 comprises: a raw material partition 24, an ultrasonic transmission substrate 24b, a stage 24c, an ultrasonic transducer 26, a guide partition 31, and an ultrasonic transmission liquid tank 35. Here, the ultrasonic transducer is surrounded by the guide partition up to the ultrasonic transmission substrate, and the guide partition 31 is in contact with the ultrasonic transmission liquid tank 35. The ultrasonic waves emitted by the ultrasonic transducer 26 are transmitted to the raw material partition 24 more efficiently through the guide partition 31.

[0067] The ultrasonic transducer is a component capable of generating ultrasonic vibrations. It is not particularly limited as long as ultrasonic waves can be irradiated onto the bottom surface of the material partition wall; any known ultrasonic transducer can be used. The frequency of the ultrasonic transducer is not particularly limited as long as it does not impede the purpose of the present invention, but is preferably 2.4 MHz or higher, more preferably 3.0 MHz or higher. For example, an acoustic transducer configured as follows: by providing electrodes on both sides of a disc-shaped piezoelectric element and connecting an oscillator to the electrodes to change the oscillation frequency, ultrasonic waves with a resonant frequency in the thickness direction and a radial resonant frequency of the piezoelectric transducer are generated. Based on this preferred range, the particle size of the mist generated by atomization can be further reduced, and the atomization efficiency can be improved.

[0068] The material partition of the present invention is not particularly limited as long as it can accommodate the atomizing material. In the present invention, it is preferable that the material partition is bottomless, and that the material partition and the ultrasonic transmission liquid tank are fitted or screwed together via an ultrasonic transmissive substrate, thereby sealing the bottom surface of the material partition with the ultrasonic transmissive substrate to allow the material partition to accommodate the atomizing material liquid. For example, when the ultrasonic transmissive substrate is a polymer film, the polymer film is clamped, and the bottom surface of the material partition is sealed by the ultrasonic transmissive substrate, thus enabling the material partition to accommodate the atomizing material liquid. The fitting or screwing mechanism between the material partition and the ultrasonic transmission liquid tank is not particularly limited as long as it does not impede the purpose of the present invention, and can be a known mechanism. As fitting mechanisms, examples include mechanisms that provide a recess, a protrusion, or a combination thereof in the raw material partition wall and place the corresponding fitting portion in the ultrasonic transmission liquid tank; or mechanisms that provide a recess, a protrusion, or a combination thereof in the ultrasonic transmission liquid tank and place the corresponding fitting portion in the raw material partition wall. As screwing mechanisms, examples include mechanisms that provide an external thread in the raw material partition wall and an internal thread in the ultrasonic transmission liquid tank; or mechanisms that provide an external thread in the ultrasonic transmission liquid tank and an internal thread in the raw material partition wall. In this invention, known components can be used to fit and screw the raw material partition wall to the ultrasonic transmission liquid tank. Furthermore, from the perspective of more effectively utilizing the ultrasonic transmissive substrate, it is preferable that the raw material partition wall and the ultrasonic transmission liquid tank have approximately the same cross-sectional shape, and also preferably have approximately the same cross-sectional area.

[0069] Furthermore, in this invention, it is preferable that the raw material partition is a covered cylindrical body with a lid. The shape of the lid is not particularly limited, as long as it can form a lid for the raw material partition. A lid that can seal the space within the raw material partition is preferred, as it further improves atomization efficiency and spray controllability. Additionally, the material of the lid is not particularly limited; it can be the same material as the raw material partition or a different material. It can be a known material, an inorganic material, or an organic material. In this invention, the material of the lid preferably includes glass, quartz, or a fluorinated resin as a main component, and more preferably, a fluorinated resin as a main component. Examples of fluorinated resins include polytetrafluoroethylene (PTFE), modified PTFE, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, or ethylene-tetrafluoroethylene copolymer.

[0070] In this invention, as described above, it is preferable that the raw material partition is a covered cylindrical body. If the raw material partition is covered, it can be sealed, and the atomizing raw material can be replenished using spatial pressure. More specifically, if the liquid level of the atomizing raw material decreases due to atomization, the spatial pressure of the raw material partition increases, and the liquid level reaches the front end of the pipe. The space of the raw material partition and the space inside the replenishment container containing the replenished atomizing raw material are connected via the pipe. Gas in the space of the raw material partition can be extracted into the space of the replenishment container via the pipe, and the atomizing raw material in the replenishment container can be replenished into the raw material partition. Having such a replenishment mechanism is also one of the preferred embodiments of this invention.

[0071] The atomizing raw material is not particularly limited as long as it can be atomized; it can be a known atomizing raw material liquid, or a liquid dispersion medium such as a sol. It can be a raw material liquid containing organic compounds or an inorganic compound. In this invention, the atomizing raw material liquid is preferably a film-forming raw material liquid, and more preferably contains metal. Examples of metals include, for example, one or more metals selected from gold (Au), silver (Ag), platinum (Pt), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), palladium (Pd), cobalt (Co), rhodium (Rh), ruthenium (Ru), chromium (Cr), molybdenum (Mo), gallium (Ga), indium (In), vanadium (V), germanium (Ge), titanium (Ti), tin (Sn), zirconium (Zr), vanadium (V), yttrium (Y), zinc (Zn), magnesium (Mg), scandium (Sc), hafnium (Hf), antimony (Sb), bismuth (Bi), tantalum (Ta), iridium (Ir), tungsten (W), niobium (Nb), lanthanum (La), cerium (Ce), and aluminum (Al). However, it is preferred that one or more metals selected from gallium, germanium, titanium, tin, niobium, vanadium, antimony, bismuth, tantalum, aluminum, and indium be included. In this invention, because it can achieve excellent film-forming effects, the atomizing feed liquid is preferably a film-forming feed liquid, and more preferably a spray CVD feed liquid. Furthermore, the atomizing feed liquid can be one type or two or more types. For example, when using two or more feed liquids, at least one type is a feed liquid containing inorganic compounds, while the others can be feed liquids containing organic compounds.

[0072] The ultrasonic transmission liquid tank of the present invention is not particularly limited as long as it can contain the ultrasonic transmission liquid. Furthermore, the shape of the ultrasonic transmission liquid tank is not particularly limited; in the present invention, it is preferably cylindrical, substantially cylindrical, polygonal, or substantially polygonal, more preferably cylindrical or substantially cylindrical, and most preferably cylindrical. The constituent material of the ultrasonic transmission liquid tank is not particularly limited; it can be inorganic or organic. In the present invention, it is preferred that the constituent material of the ultrasonic transmission liquid tank contains glass, quartz, or fluorinated resin as a main component, and more preferably fluorinated resin as a main component. The ultrasonic transmission liquid is not particularly limited as long as it is a liquid capable of transmitting ultrasonic waves, and also includes liquid dispersion media such as sols. Examples of ultrasonic transmission liquids include inorganic solvents and organic solvents; in the present invention, an inorganic solvent is preferred, and water is more preferably used. The water mentioned, more specifically, includes, for example, pure water, ultrapure water, tap water, well water, mineral water, mineralized water, hot spring water, spring water, fresh water, seawater, etc. Water that has undergone treatments such as purification, heating, sterilization, filtration, ion exchange, electrolysis, osmotic pressure adjustment, buffering, etc. (e.g., ozone water, purified water, hot water, ion-exchanged water, physiological saline, phosphate buffer, phosphate-buffered saline, etc.) is also included as an example. Furthermore, in this invention, it is preferable to keep the interior of the ultrasonic transmission liquid tank in a sealed state. By forming a sealed space, the atomization efficiency and spray controllability can be improved.

[0073] The ultrasonic transmissive substrate is not particularly limited as long as it does not impede the purpose of the present invention, and can be any known ultrasonic transmissive substrate. Examples of ultrasonic transmissive substrates include, for example, polymer films. Examples of constituent materials of the ultrasonic transmissive substrate include thermoplastic resins or thermosetting resins; in the present invention, thermoplastic resins are preferred. Examples of thermoplastic resins include, for example, polyolefins and fluorinated resins, wherein a fluorinated resin is preferably included as a main component. Examples of polyolefins include, for example, polyethylene and polypropylene. Examples of fluorinated resins include, for example, polytetrafluoroethylene, modified polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, or ethylene-tetrafluoroethylene copolymers. In the present invention, the fluorinated resin is preferably at least one selected from polytetrafluoroethylene, modified polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, and ethylene-tetrafluoroethylene copolymers.

[0074] Based on this optimized range, ultrasonic waves can be transmitted to the atomizing material more efficiently, thereby further increasing the atomization volume.

[0075] The material of the guide partition is not particularly limited as long as it does not impede the purpose of the present invention; for example, metals or polymers can be included. Furthermore, the polymers can include, for example, natural resins, thermoplastic resins, or thermosetting resins. Additionally, the guide partition can be coated with a metal. Examples of metals include Al, Cu, Ag, Ti, W, Mo, Fe, Ni, Cr, Zn, Sn, Rh, Pt, and Au. According to this preferred range, the transmission of ultrasonic vibrations can be more efficient and effective. The shape of the guide partition is not particularly limited as long as it does not impede the purpose of the present invention, but according to this embodiment, a cylindrical or substantially cylindrical or polygonal cylindrical or substantially polygonal cylindrical shape is preferred. Furthermore, a frustum shape is also preferred, more preferably a frustum shape or substantially cylindrical shape, and most preferably a frustum shape. Furthermore, the guide partition is preferably through-hole-shaped as long as it does not impede the purpose of the present invention and is not particularly obstructed. According to this preferred range, ultrasonic waves irradiated by the ultrasonic transducer can be transmitted to the ultrasonic transmission substrate more efficiently and effectively. The guide partition is not particularly limited as long as it does not impede the purpose of the invention. It can be detachably constructed or disposed on the ultrasonic emitting surface, but in the present invention, it is preferably detachably constructed. According to this preferred range, the atomizing device of the present invention can be cleaned more easily.

[0076] When adjusting the feed solution for atomization, 2.093 g of germanium dioxide powder with a hexagonal crystal structure was dissolved in ultrapure water under an ultrasonic atmosphere to achieve a concentration of 0.02 mol / L. Furthermore, the solution was adjusted to contain 20% hydrochloric acid by volume, thus becoming an aqueous germanium dioxide solution. This solution was used as the feed solution for atomization.

[0077] Next, as the film-forming sample 20, a TiO2 (001) substrate with a rutile crystal structure, square with one side of 15 mm and an average thickness of 500 μm, was placed on the sample stage 21. The heater 28 was activated to raise the temperature inside the film-forming chamber 27 to 700°C. Then, the flow regulating valve 23 was opened, and carrier gas was supplied from the carrier gas source 22 into the film-forming chamber 27. After the atmosphere in the film-forming chamber 27 was fully replaced with the carrier gas, the flow rate of the carrier gas was adjusted to 1 L / min. Nitrogen gas was used as the carrier gas. Furthermore, the TiO2 (001) substrate with the rutile crystal structure attached to the GeO2 crystalline film with the aforementioned rutile crystal structure was obtained by using 0.02 mol / L of bis[2-carboxyethylgermanium(IV)] sesquioxide (C6H) in the atomization feed solution instead of the germanium dioxide aqueous solution. 10The atomized raw material solution containing 20% ​​hydrochloric acid by volume in an aqueous solution of Ge2O7 is used, and otherwise the same method is used to fabricate a GeO2 crystal film with a rutile crystal structure on a TiO2 (001) substrate with a rutile crystal structure.

[0078] Next, the ultrasonic transducer 26 is vibrated at 3.0 MHz, and this vibration is propagated through the ultrasonic transmitter 25a to the atomized feed solution 24a, thereby microparticle-forming the feed solution 24a into feed microparticles. These feed microparticles are introduced into the film-forming chamber 27 by a carrier gas, where a reaction takes place. Through CVD reaction on the film-forming surface of the sample 20, a tetragonal GeO2 crystalline film is formed on the sample 20. The film thickness is 900 nm.

[0079] The obtained GeO2 crystalline film was measured using an X-ray diffraction apparatus. Figure 3 This is a graph showing the 2θ / ω results of the XRD diffraction. (From...) Figure 3 It is clearly known that the obtained crystalline film is a single-crystal GeO2 film with a tetragonal (002) orientation and a rutile structure. Furthermore, the results of the ω-scan in the X-ray diffraction measurements show... Figure 4 According to Figure 4 The full width at half maximum (FWHM) of the rocking curve of the 002 diffraction peak of r-GeO2 is 474 arcsec. Based on this result, a GeO2 crystalline film with good crystallinity was formed on a TiO2 (001) substrate with a rutile crystal structure.

[0080] In addition, when observing the surface of the obtained GeO2 crystalline film using atomic force microscopy (AFM), such as... Figure 5 As shown, the surface roughness (RMS) based on JIS B0601 is 24.5 nm, indicating that the surface smoothness is superior.

[0081] In addition, the surface of the obtained GeO2 crystalline film was observed using SEM. Figure 6 The image shown is a SEM image. (By...) Figure 6 It is clearly known that GeO2 crystals with excellent surface smoothness and good crystallinity are formed. Furthermore, when evaluating the surface of the obtained crystalline film using EDS, such as... Figure 7 As shown, it can be seen that the entire surface, covering 100mm... 2 A crystalline film is formed over the area mentioned above.

[0082] Furthermore, the carbon concentration in the obtained GeO2 single crystal film, confirmed by SIMS measurement, was 1 × 10⁻⁶. 18 cm －3 the following.

[0083] (Example 2)

[0084] Antimony chloride (SbCl3) was added at a molar ratio of 0.5 mol% relative to the molar concentration of germanium dioxide in the aqueous GeO2 solution contained in the atomizing feed solution. Otherwise, the film formation was performed in the same manner as in Example 1. The resulting crystalline film was measured using X-ray diffraction. Figure 8 The 2θ / ω result of the XRD diffraction is shown in the figure. (From...) Figure 8 It is clearly known that the obtained crystalline film is a GeO2 single crystal film with a tetragonal rutile structure and (002) orientation. According to Figure 9 The full width at half maximum (FWHM) of the rocking curve for the 002 diffraction peak of r-GeO2 is 433 arcsec. A GeO2 crystalline film with good crystallinity was formed on a TiO2(001) substrate with a rutile crystal structure. The film thickness is 190 nm.

[0085] To evaluate the electrical properties of the obtained film, Hall effect measurements were performed using the van der Pauw method. The measurement environment was a magnetic field with a frequency of 50 mHz applied at room temperature. The resulting carrier density was 1.46 × 10⁻⁶. 20 (1 / cm) 3 The mobility is 21 (cm). 2 ( / V·s). Additionally, the sheet resistance is 1.08 × 10⁻⁶. 2 (Ω / □). Resistivity is 2.06 × 10⁻⁶. ―3 Ωcm. Furthermore, the carrier type is "n". These results indicate that the obtained crystalline film possesses superior electrical properties.

[0086] Indium is used on the obtained crystalline film. Figure 12 An ohmic electrode was formed as shown, and ohmic measurements were performed. The results are shown in... Figure 13 In the middle. For example Figure 13 It is clear that it has excellent ohmic properties.

[0087] Furthermore, the carbon concentration in the obtained GeO2 single crystal film, confirmed by SIMS measurement, was 1 × 10⁻⁶. 18 cm －3 the following.

[0088] (Example 3)

[0089] Except for the conversion of the carrier gas to oxygen, the film preparation process was the same as in Example 2. The resulting crystalline film was measured using an X-ray diffraction apparatus. Figure 10 The image shows the 2θ / ω result from the XRD diffraction. (From...) Figure 10 It is clearly known that the obtained crystalline film is a GeO2 single crystal film with a tetragonal rutile structure and (002) orientation. According to Figure 11 The half-width at half-maximum (FWHM) of the rocking curve for the 002 diffraction peak of r-GeO2 is 690 arcsec. A GeO2 crystalline film with good crystallinity was formed on a TiO2 (001) substrate with a rutile crystal structure. The film thickness is 80 nm.

[0090] To evaluate the electrical properties of the obtained film, Hall effect measurements were performed using the van der Pauw method. The measurement environment was room temperature, with an applied magnetic field frequency of 50 mHz. The resulting carrier density was 1.12 × 10⁻⁶. 19 (1 / cm) 3 The migration rate was 19 (cm). 2 ( / V·s). Additionally, the sheet resistance is 3.75 × 10⁻⁶. 3 (Ω / □). Resistivity is 3.00 × 10⁻⁶. ―2 Ωcm. Furthermore, the carrier type is "n". These results indicate that the obtained crystalline film possesses superior electrical properties.

[0091] Indium is used on the obtained crystalline film. Figure 16 An ohmic electrode was formed as shown, and ohmic measurements were performed. The results are shown in... Figure 17 In the middle. For example Figure 17 It is clear that it has excellent ohmic properties.

[0092] Furthermore, the carbon concentration in the obtained GeO2 single crystal film, confirmed by SIMS measurement, was 1 × 10⁻⁶. 18 cm －3 the following.

[0093] (Comparative Example 1)

[0094] The atomizing feed solution is in bis[2-carboxyethylgermanium(IV)] sesquioxide (C6H 10 An atomizing feed solution containing 20% ​​hydrochloric acid by volume in a 0.02 mol / L aqueous solution of Ge2O7 was prepared, and antimony chloride (SbCl3) was added at a molar ratio of 3.0 mol% relative to the molar concentration of bis[2-carboxyethylgermanium(IV)] sesquioxide in the atomizing feed solution. Otherwise, the preparation was performed in the same manner as in Example 1. The electrical properties of the obtained membrane were evaluated by Hall effect measurements using the van der Pauw method. The measurement environment was room temperature, and the applied magnetic field frequency was 50 mHz. The result was a carrier density of 1.12 × 10⁻⁶. 20 (1 / cm) 3), with a mobility of 6 (cm). 2 ( / V·s). Additionally, the sheet resistance is 2.88 × 10⁻⁶. 3 (Ω / □). Resistivity is 5.76 × 10⁻⁶. ―3 Ωcm. Additionally, the carrier type is "n".

[0095] The comparison results between Example 2 and Comparative Example 1 show that Example 2 has improved mobility, reduced resistivity, and superior electrical characteristics.

[0096] (Experimental Example 1)

[0097] As a comparative example, the atomized feed solution was prepared using bis[2-carboxyethylgermanium(IV)] sesquioxide (C6H2O) 10 The atomizing feed solution (hereinafter referred to as Solution A) was prepared in the form of a 0.02 mol / L aqueous solution of Ge2O7 containing 20% ​​hydrochloric acid by volume. Except for this, a GeO2 crystalline film was prepared on a TiO2 (001) substrate in the same manner as in Example 1. The film thickness was 440 nm.

[0098] Furthermore, after preparing a GeO2 crystalline film as a comparative example, a GeO2 crystalline film as an example was prepared by using the atomization raw material solution (hereinafter referred to as Solution B) used in Example 1 on the prepared GeO2 crystalline film. The preparation conditions were the same as in Example 1. Also, the thickness of the GeO2 crystalline film as an example was 1.11 μm.

[0099] Subsequently, during SIMS measurements, the carbon content in the crystalline film prepared from solution B was found to be 3.57 × 10⁻⁶. 17 atoms / cc. Furthermore, the carbon content in the crystalline film prepared from solution A is 6.55 × 10⁻⁶. 19 atoms / cc. SIMS measurements show... Figure 15 Based on this result, by using an aqueous solution of germanium dioxide, it is possible to obtain a crystalline film with a reduced carbon content in the GeO2 crystalline film.

[0100] Industrial availability

[0101] The manufacturing method of the present invention is used in the manufacture of crystals, such as those used in semiconductor devices (e.g., compound semiconductor electronic devices), electronic components, electrical equipment components, optical and electrophotographic related devices, and industrial components.

[0102] Explanation of reference numerals in the attached figures

[0103] 19 Film Forming Device

[0104] 20 film-forming samples

[0105] 21 Sample Platform

[0106] 22a Carrier Gas Source

[0107] 22b Dilution gas source

[0108] 23a Flow regulating valve

[0109] 23b Flow regulating valve

[0110] 24 Raw material partition

[0111] 24a Feed solution for atomization

[0112] 24b Ultrasonic transmission substrate

[0113] 24c stage

[0114] 26. Ultrasonic transducer

[0115] 27 Film Forming Room

[0116] 28 Heaters

[0117] 30 Atomizing device

[0118] 31 Guide Block

[0119] 33. Dilution gas supply pipe

[0120] 34 Carrier gas supply pipe

[0121] 35 Ultrasonic transmission tank

[0122] 36 Ultrasonic Transmitter Fluid

[0123] 37 Film Forming Room

Claims

1. A manufacturing method, characterized in that, It is a method of manufacturing crystals by causing a reaction of raw materials to grow crystals, wherein the raw materials include a substance formed by dissolving or dispersing germanium dioxide powder in water.

2. The manufacturing method according to claim 1, wherein, The raw materials also contain acid.

3. The manufacturing method according to claim 1, wherein, The acid contains elements from group 17 of the periodic table.

4. The manufacturing method according to claim 1, wherein, The germanium dioxide powder has a crystal structure that includes a hexagonal crystal system or an amorphous phase.

5. The manufacturing method according to claim 1, wherein, It also includes the process of atomizing or dropletizing the raw material.

6. The manufacturing method according to claim 5, wherein, This includes the process of conveying the atomized or dropletized raw material via gas.

7. The manufacturing method according to claim 1, wherein, The reaction is carried out in an oxygen atmosphere or an inactive atmosphere.

8. The manufacturing method according to claim 1, wherein, The reaction is a thermal reaction carried out at temperatures above 500°C and below 1000°C.

9. The manufacturing method according to claim 1, wherein, The crystal growth is performed on a substrate.

10. The manufacturing method according to claim 9, wherein, The substrate is a crystal substrate.

11. The manufacturing method according to claim 10, wherein, The crystal substrate has a rutile structure.

12. A manufacturing method, characterized in that, This is a method for manufacturing epitaxial wafers by growing a crystalline film on a crystal substrate through a reaction of raw materials, wherein the raw materials contain a substance formed by dissolving or dispersing germanium dioxide powder in water.

13. The manufacturing method according to claim 12, wherein, The crystal substrate has a rutile structure.

14. The manufacturing method according to claim 12, wherein, The raw material contains dopants.

15. The manufacturing method according to claim 12, wherein, The dopant contains at least one element from Group 13 or Group 15 of the periodic table.

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