WO2024009705A1 - Procédé de fabrication de tranche épitaxiale - Google Patents

Procédé de fabrication de tranche épitaxiale Download PDF

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WO2024009705A1
WO2024009705A1 PCT/JP2023/021921 JP2023021921W WO2024009705A1 WO 2024009705 A1 WO2024009705 A1 WO 2024009705A1 JP 2023021921 W JP2023021921 W JP 2023021921W WO 2024009705 A1 WO2024009705 A1 WO 2024009705A1
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crystal silicon
oxide film
single crystal
epitaxial
manufacturing
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Japanese (ja)
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克佳 鈴木
温 鈴木
剛 大槻
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信越半導体株式会社
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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/02—Elements
    • C30B29/06—Silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/20—Deposition of semiconductor materials on a substrate, e.g. epitaxial growth solid phase epitaxy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/20—Deposition of semiconductor materials on a substrate, e.g. epitaxial growth solid phase epitaxy
    • H01L21/2003—Deposition of semiconductor materials on a substrate, e.g. epitaxial growth solid phase epitaxy characterised by the substrate
    • H01L21/2015—Deposition of semiconductor materials on a substrate, e.g. epitaxial growth solid phase epitaxy characterised by the substrate the substrate being of crystalline semiconductor material, e.g. lattice adaptation, heteroepitaxy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/322—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to modify their internal properties, e.g. to produce internal imperfections

Definitions

  • the present invention relates to a method for manufacturing an epitaxial wafer.
  • Silicon substrates that form semiconductor devices such as solid-state image sensors and other transistors are required to have the function of gettering heavy metals and other elements that disrupt device characteristics.
  • gettering there are methods such as providing a polycrystalline silicon (Poly-Si) layer on the back surface of the silicon substrate, forming a damaged layer by blasting, using a silicon substrate with a high concentration of boron, and removing precipitates.
  • Various methods have been proposed and put into practical use, such as forming .
  • gettering by oxygen precipitation gettering is performed by incorporating a metal with a high ionization tendency (low electronegativity) against oxygen, which has high electronegativity.
  • proximity gettering in which a gettering layer is formed near the active region of the element, has been proposed.
  • a substrate in which silicon is epitaxially grown on a substrate into which carbon ions are implanted.
  • Gettering requires elements to diffuse to gettering sites (the energy of the entire system is lowered by bonding and clustering at sites rather than by metals existing as a single element).
  • the diffusion coefficient of metal elements contained in silicon differs depending on the element, and in consideration of the fact that metals cannot diffuse to the gettering site due to recent lower process temperatures, a method of proximity gettering has been proposed. .
  • oxygen can be used for proximity gettering, it is thought that the silicon substrate will have a very effective gettering layer.
  • the epitaxial wafer has an oxygen atomic layer in the middle of the epitaxial layer, metal impurities can be reliably gettered even in recent low-temperature processes.
  • Patent Document 1 is a method in which a thin layer of oxygen is formed on silicon and then silicon is further grown.
  • This method is a technology based on ALD ( ⁇ atomic layer deposition'').
  • ALD is a method in which molecules containing target atoms are adsorbed, and then unnecessary atoms (molecules) in the molecules are dissociated and released.It uses surface bonding, has very high precision, and has good reaction controllability. Yes, and widely used.
  • Patent Document 2 describes a method in which a natural oxide film is formed on a silicon clean surface formed by vacuum heating or the like, and then an oxide film or another substance is adsorbed and deposited.
  • Patent Documents 3 and 4 show that by introducing multiple oxygen atomic layers into a silicon substrate, it is possible to improve device characteristics and (mobility).
  • Patent Document 5 shows a method of forming an epitaxial layer using SiH 4 gas on an atomic layer having a thickness of 5 nm or less. Furthermore, a method of forming an oxygen atomic layer using oxygen gas is shown.
  • Patent Documents 6 and 7 describe a method of epitaxially growing single crystal silicon after forming an oxide film by bringing the surface of a semiconductor substrate into contact with an oxidizing gas or an oxidizing solution. Further, Patent Document 6 describes a method in which a silicon film forming gas is flowed after flowing an oxidizing gas.
  • Patent Document 8 describes a method in which a natural oxide film on the surface of a wafer made of group IV elements is removed, the wafer is oxidized to form an oxygen atomic layer, and then single crystal silicon is epitaxially grown.
  • Patent Document 9 describes a method in which a precursor containing oxygen is supplied to a CVD epitaxy furnace to form an oxygen-inserted monolayer, and then a silicon epitaxial layer is formed.
  • Non-Patent Document 1 shows a method of removing a natural oxide film with HF, oxidizing it in the atmosphere, forming an amorphous silicon film by low pressure CVD, and then forming single crystal silicon by crystallization heat treatment.
  • Japanese Patent Application Publication No. 2014-165494 Japanese Patent Application Publication No. 05-243266 US Patent No. 7,153,763 US Patent No. 7,265,002 JP2019-004050A Japanese Patent Application Publication No. 2008-263025 Japanese Patent Application Publication No. 2009-016637 JP 2021-111696 Publication JP2022-22194A
  • Patent Documents 5 and 9 have a problem in that it is necessary to prepare two chambers with separate exhaust systems in order to prevent SiH 4 and oxygen from reacting and exploding.
  • Patent Document 6 has a problem in that a special device with safety in mind is required to prevent the oxidizing gas and the silicon film-forming gas from reacting and exploding.
  • Non-Patent Document 1 requires heat treatment during crystallization, which has the problem of increasing the number of process steps. Furthermore, since amorphous silicon generally contains a large amount of hydrogen, there is a possibility that hydrogen-related defects may be formed during crystallization heat treatment.
  • Patent Document 8 has the problem that, in addition to requiring long-time oxidation to form an oxygen atomic layer, it is difficult to make the oxygen concentration uniform within the wafer surface.
  • the conventional technology has a problem in that there is no description for stably introducing an oxygen layer or specific description for forming an epitaxial layer of high quality single crystal silicon.
  • Patent Document 2 does not describe any method for forming an epitaxial layer of single crystal silicon on a wafer surface without generating dislocations or stacking faults.
  • Patent Documents 3 and 4 do not mention a specific method for growing a silicon wafer into which multiple oxygen atomic layers are introduced.
  • Patent Documents 6 and 7 do not describe a method for removing a natural oxide film before contacting with an oxidizing gas or an oxidizing solution.
  • the present invention has been made in view of the above-mentioned problems of the prior art, and is capable of stably and easily introducing an oxygen atomic layer into an epitaxial layer, as well as an epitaxial layer having a high-quality single-crystal silicon epitaxial layer.
  • An object of the present invention is to provide an epitaxial wafer manufacturing method that can manufacture wafers.
  • the present invention provides an epitaxial wafer manufacturing method for forming a single crystal silicon epitaxial layer on a single crystal silicon wafer, comprising: A process of removing a natural oxide film from the surface of a single crystal silicon wafer, After removing the natural oxide film, forming an oxide film on the surface of the single crystal silicon wafer using an oxidizing solution; After forming the oxide film, thinning the oxide film to form an oxygen atomic layer; and After forming the oxygen atomic layer, forming a single crystal on the surface of the single crystal silicon wafer having the oxygen atomic layer.
  • a method for manufacturing an epitaxial wafer is provided, which includes a step of epitaxially growing silicon.
  • single crystal silicon can be grown without forming dislocations or stacking faults on the surface of a single crystal silicon wafer having an oxygen atomic layer while leaving the oxygen atomic layer. That is, with the epitaxial wafer manufacturing method of the present invention, an oxygen atomic layer can be stably and easily introduced into an epitaxial layer, and an epitaxial wafer having a high-quality single-crystal silicon epitaxial layer can be manufactured.
  • the natural oxide film can be removed using a solution containing hydrofluoric acid.
  • an SC1 solution hydrogen peroxide solution, or ozone water can be used.
  • an oxide film can be easily formed in a short time.
  • the SC1 solution or the hydrogen peroxide solution can be used as the oxidizing solution, and the temperature of the SC1 solution or the hydrogen peroxide solution can be set to 20° C. or higher and 80° C. or lower.
  • single-crystal silicon wafers can be easily oxidized without the need for special equipment.
  • the ozone water can be used as the oxidizing solution, and the temperature of the ozone water can be set to 10°C or more and 30°C or less.
  • the wafer can be reliably oxidized.
  • the oxide film can be thinned by heating the single crystal silicon wafer in a hydrogen atmosphere.
  • the heating temperature in the hydrogen atmosphere can be set to 600° C. or higher and 1250° C. or lower.
  • the oxide film can be thinned by plasma using a gas containing hydrogen atoms or plasma using an inert gas.
  • the oxide film can be thinned by sputtering with high-energy particles generated by the plasma.
  • the single crystal silicon in the step of epitaxially growing the single crystal silicon, can be epitaxially grown at a temperature of 450° C. or higher and 800° C. or lower.
  • the partial pressure of the silicon source gas can be set to 0.1 Pa or more and 2000 Pa or less.
  • single crystal silicon can be epitaxially grown more stably without generating defects.
  • planar concentration of oxygen in the oxygen atomic layer can be 6 ⁇ 10 14 atoms/cm 2 or less.
  • epitaxial wafers can be stably manufactured without generating defects.
  • the steps of forming the oxide film, forming the oxygen atomic layer, and epitaxially growing the single crystal silicon can be repeated.
  • an oxygen atomic layer can be stably and easily introduced into the epitaxial layer, and an epitaxial layer of high-quality single crystal silicon can be introduced into the epitaxial layer. It is possible to provide a method for manufacturing an epitaxial wafer having the following. Furthermore, it becomes possible to manufacture a proximity gettering substrate having a proximity gettering effect due to the oxygen atomic layer.
  • FIG. 2 is a diagram showing a flow of the method for manufacturing an epitaxial wafer of the present invention.
  • 1 is a schematic cross-sectional view of an example of an epitaxial wafer that can be manufactured by the method for manufacturing an epitaxial wafer of the present invention. It is a schematic sectional view of another example of an epitaxial wafer which can be manufactured by the manufacturing method of an epitaxial wafer of the present invention.
  • 2 is a graph showing the relationship between heating time and oxygen concentration in a hydrogen atmosphere in Example 1 and Comparative Example 1.
  • 2 is a graph showing the distribution of oxygen concentration in an oxygen atomic layer within the plane of a substrate in Example 1 and Comparative Example 2.
  • an epitaxial wafer that does not require special equipment or complicated processes, can stably and easily introduce an oxygen atomic layer into an epitaxial layer, and has an epitaxial layer of high-quality single crystal silicon.
  • the present inventor has devised a method for manufacturing an epitaxial wafer in which a single crystal silicon epitaxial layer is formed on a single crystal silicon wafer, in which a natural oxide film is removed from the surface of the single crystal silicon wafer. After removing the natural oxide film, forming an oxide film on the surface of the single crystal silicon wafer using an oxidizing solution; After forming the oxide film, thinning the oxide film to form an oxygen atomic layer. and after forming the oxygen atomic layer, epitaxially growing single crystal silicon on the surface of the single crystal silicon wafer having the oxygen atomic layer.
  • the present invention has been completed by discovering that it is possible to stably and easily introduce an oxygen atomic layer into an epitaxial layer of silicon without forming dislocations or stacking faults on the epitaxial layer.
  • the present invention is an epitaxial wafer manufacturing method for forming a single-crystal silicon epitaxial layer on a single-crystal silicon wafer, comprising: A process of removing a natural oxide film from the surface of a single crystal silicon wafer, After removing the natural oxide film, forming an oxide film on the surface of the single crystal silicon wafer using an oxidizing solution; After forming the oxide film, thinning the oxide film to form an oxygen atomic layer; and After forming the oxygen atomic layer, forming a single crystal on the surface of the single crystal silicon wafer having the oxygen atomic layer.
  • This is a method for manufacturing an epitaxial wafer, characterized by including a step of epitaxially growing silicon.
  • an epitaxial wafer 10A whose cross section is schematically shown in FIG. 2, for example, can be manufactured.
  • the epitaxial wafer that can be manufactured by the epitaxial wafer manufacturing method of the present invention is not limited to that shown in FIG. 2.
  • the epitaxial wafer 10A shown in FIG. 2 has a single crystal epitaxial silicon layer (hereinafter sometimes simply referred to as an epitaxial layer) 3 on a single crystal silicon wafer 1, and has a single crystal epitaxial silicon layer 3 and a single crystal silicon wafer 1. There is an oxygen atomic layer 2 between them.
  • FIG. 1 shows the flow of the method for manufacturing an epitaxial wafer according to the present invention.
  • the step S11 in FIG. 1 is a step of preparing a single crystal silicon wafer.
  • the method for manufacturing the single crystal silicon wafer is not particularly limited.
  • a substrate manufactured by the Czochralski Method (hereinafter referred to as the CZ method) may be used, or a substrate manufactured by the Floating Zone Method (hereinafter referred to as the FZ method) may be used.
  • a substrate in which single crystal silicon is epitaxially grown on a single crystal silicon substrate manufactured by the CZ method or the FZ method may be used.
  • S12 in FIG. 1 is a step of removing a natural oxide film from the surface of the single crystal silicon wafer prepared in step S11.
  • the natural oxide film can be removed using a solution containing hydrofluoric acid.
  • hydrofluoric acid or buffered hydrofluoric acid may be used.
  • Buffered hydrofluoric acid is a solution containing hydrofluoric acid and ammonium fluoride.
  • the concentration of hydrofluoric acid in the solution containing hydrofluoric acid may be any concentration that can remove the native oxide film, and may be, for example, 0.001% or more and 60% or less.
  • the temperature of the solution containing hydrofluoric acid can be, for example, 10°C or higher and 50°C or lower. When the temperature is 10° C. or higher, it is possible to prevent dew condensation from forming on the wafer after processing with a solution containing hydrofluoric acid. Further, by setting the temperature to 50° C. or lower, the amount of hydrofluoric acid that evaporates can be suppressed, and safety problems can be avoided.
  • the time for cleaning with a solution containing hydrofluoric acid can be, for example, until water repellency is confirmed, and can be, for example, 1 second or more and 1 hour or less. If the time is 1 second or more, the natural oxide film can be removed. Further, by setting the time to 1 hour or less, it is possible to prevent it from taking too much time.
  • a batch type cleaning device or a single wafer type cleaning device may be used.
  • the natural oxide film may be removed using vapor of a solution containing hydrofluoric acid.
  • S13 in FIG. 1 is a step of forming an oxide film on the surface of the single crystal silicon wafer using an oxidizing solution after removing the natural oxide film in step S12.
  • a hydrophobic surface without an oxide film tends to attract particles, but a hydrophilic surface with an oxide film can prevent particles from adhering. For this reason, for example, by immersing a single crystal silicon wafer in an oxidizing solution to form an oxide film on the surface, particles can be prevented from adhering to the single crystal silicon wafer before it is transported from the cleaning equipment to the next process. It can be prevented.
  • a batch type device or a single wafer type device may be used, for example.
  • oxidizing solution for example, SC1 solution, hydrogen peroxide solution, or ozone water can be used.
  • an oxide film can be easily formed in a short time.
  • the SC1 solution is a solution that is a mixture of ammonia, hydrogen peroxide, and water, and the hydrogen peroxide solution oxidizes the surface of a single-crystal silicon wafer, while the ammonia etches the oxide film. With this, particles attached to the surface of the single crystal silicon wafer can be lifted off and removed. Therefore, by using the SC1 solution used in the cleaning process of single crystal silicon substrates, an oxide film is formed on the surface of the single crystal silicon wafer.
  • the mixing ratio between each component in the SC1 solution it is preferable that the amount of hydrogen peroxide solution is larger than that of aqueous ammonia. With such a mixing ratio, an oxide film can be formed stably and uniformly.
  • the mixing ratio of aqueous ammonia (NH 3 concentration: 28%), hydrogen peroxide solution (H 2 O 2 concentration: 30%), and water can be 1:1 to 2:5 to 100.
  • the time for immersing the single crystal silicon wafer in the SC1 solution can be, for example, 1 second or more and 1 hour or less. If the heating time is 1 second or more, an oxygen atomic layer can be sufficiently formed. Further, by setting the time to 1 hour or less, it is possible to prevent it from taking too much time.
  • the concentration of the hydrogen peroxide solution can be set to 0.01% or more and 30% or less, for example. If the concentration is 0.01% or more, an oxide film can be reliably formed. Further, if the concentration is 30% or less, the amount of evaporation of hydrogen peroxide from the cleaning liquid can be maintained at an appropriate level, so that an increase in the burden on the disposal equipment can be prevented.
  • the time for immersing the single crystal silicon wafer in the hydrogen peroxide solution can be, for example, 1 second or more and 1 hour or less. If the time is 1 second or more, an oxygen atomic layer can be formed. Further, by setting the time to 1 hour or less, it is possible to prevent it from taking too much time.
  • the temperature of the SC1 solution or the hydrogen peroxide solution as the oxidizing solution can be, for example, 20°C or higher and 80°C or lower. If the temperature is 20° C. or higher, an oxide film can be stably formed. Further, if the temperature is 80° C. or lower, the amount of evaporation of the cleaning liquid can be kept constant and bubbles can be prevented from increasing in the cleaning liquid, so that an oxide film can be formed uniformly within the wafer surface. That is, at such a temperature, a single crystal silicon wafer can be easily oxidized without preparing special equipment.
  • ozone water is used to decompose organic matter and oxidize the surface of the single crystal silicon wafer.
  • the ozone concentration of the ozone water can be, for example, 1 ppm or more and 500 ppm or less.
  • the ozone concentration is 1 ppm or more, an oxide film can be stably formed on the surface of the single crystal silicon wafer.
  • the ozone concentration is 500 ppm or less, it is possible to prevent variations in the oxide film thickness due to fluctuations in the ozone concentration due to ozone decomposition or escape into the gas phase.
  • the temperature of the ozone water can be, for example, 10°C or higher and 30°C or lower.
  • the temperature can be, for example, 10°C or higher and 30°C or lower.
  • 10° C. or higher it is possible to prevent dew condensation from occurring on the wafer after the ozone water treatment.
  • the temperature to 30° C. or lower, it is possible to prevent ozone from decomposing in ozone water or from escaping into the gas phase, thereby making it possible to reliably oxidize the single crystal silicon wafer.
  • the time for immersing the single crystal silicon wafer in ozone water can be, for example, 1 second or more and 1 hour or less. If the time is 1 second or more, an oxygen atomic layer can be formed. Further, by setting the time to 1 hour or less, it is possible to prevent it from taking too much time.
  • S14 in FIG. 1 is a step in which, after forming the oxide film in step S13, the oxide film is thinned to form an oxygen atomic layer.
  • the oxide film can be thinned, for example, by heating a single crystal silicon wafer in a hydrogen atmosphere. By performing heat treatment in a hydrogen atmosphere in this manner, the oxide film can be reduced uniformly and stably, thereby making it possible to reduce the thickness of the oxide film.
  • Heating may be performed in an atmospheric pressure environment or in a reduced pressure environment.
  • the reduced pressure environment refers to, for example, an environment of 100 Pa or more and less than atmospheric pressure.
  • the hydrogen atmosphere for example, an atmosphere containing 100% hydrogen may be used, or an atmosphere containing a mixture of hydrogen and an inert gas may be used.
  • the inert gas any one of nitrogen, helium, neon, argon, krypton, and xenon can be used.
  • the heating temperature can be, for example, 600°C or higher and 1250°C or lower.
  • the oxide film can be reliably reduced and made thinner.
  • a general-purpose heating device can be used.
  • the heating time can be, for example, 1 second or more and 1 hour or less. If the time is 1 second or more, the oxide film can be reduced and made thinner. Further, by setting the time to 1 hour or less, it is possible to prevent it from taking too much time.
  • the above pressure, heating temperature, and heating time can be changed depending on the thickness of the oxide film.
  • the oxide film When the oxide film is thick, the oxide film can be made thinner and an oxygen atomic layer can be formed by increasing the pressure, temperature, or lengthening the heating time.
  • the oxide film When the oxide film is thin, the oxide film can be completely removed and the oxygen atomic layer can be prevented from disappearing by lowering the pressure, lowering the temperature, or shortening the heating time.
  • Heating of the single crystal silicon wafer in a hydrogen atmosphere may be performed in a heat treatment furnace or in a single crystal silicon film forming apparatus.
  • the heating device may be a batch type or a single wafer type.
  • the thinning of the oxide film in step S14 can be performed by plasma using a gas containing hydrogen atoms or plasma using an inert gas.
  • a gas containing hydrogen atoms for example, hydrogen molecules, ammonia, nitrogen, argon, helium, neon, krypton, or xenon can be used. These gases may be used in combination.
  • hydrogen radicals generated by plasma can stably reduce the oxide film at low temperatures and make it thin.
  • the oxide film can be thinned by sputtering with high-energy particles generated by plasma.
  • the oxide film when the oxide film is thinned using the plasma, it may be performed at room temperature or may be performed by heating.
  • the time for exposing the single crystal silicon wafer to plasma depends on the plasma density, ion energy, etc., but by setting it to, for example, 1 second or more and 30 minutes or less, the oxide film can be stably thinned.
  • the time of exposure to plasma can be changed depending on the thickness of the oxide film.
  • the oxide film can be made thinner to form an oxygen atomic layer by increasing the plasma exposure time.
  • the oxide film is thin, by shortening the time of exposure to plasma, it is possible to prevent the oxide film from being completely removed and the oxygen atomic layer disappearing.
  • S15 in FIG. 1 is a step of epitaxially growing single crystal silicon on the surface of the single crystal silicon wafer having the oxygen atomic layer after forming the oxygen atomic layer in step S14.
  • monosilane and disilane can be used as the gas used for epitaxial growth.
  • Nitrogen and hydrogen may also be used as carrier gases.
  • the pressure in the chamber may be any pressure that does not cause a gas phase reaction.
  • a batch type or a single wafer type may be used as the epitaxial growth apparatus.
  • epitaxial growth of single crystal silicon can be performed at a temperature of, for example, 450° C. or higher and 800° C. or lower.
  • a temperature of, for example, 450° C. or higher and 800° C. or lower.
  • the film formation time can be adjusted to adjust the thickness of the epitaxial layer. Furthermore, when forming a film at a high temperature, by shortening the film forming time, it is possible to prevent oxygen from diffusing outward from the single crystal silicon wafer and reducing the heat resistance of the oxygen atomic layer.
  • epitaxial growth of single-crystal silicon can be performed, for example, with the partial pressure of the silicon source gas set to 0.1 Pa or more and 2000 Pa or less. Within this pressure range, single crystal silicon can be more stably formed without generating dislocations or stacking faults on the oxygen atomic layer.
  • step S14 of forming an oxygen atomic layer by setting the plane concentration of oxygen in the oxygen atomic layer to 6 ⁇ 10 14 atoms/cm 2 or less, no defects are formed in the epitaxial layer. This is because the crystallinity of the single crystal silicon wafer is maintained when the amount of oxidation (planar concentration of oxygen in the oxygen atomic layer) is small. Therefore, there is no lower limit to the plane concentration of oxygen, and it is sufficient that it is greater than 0. If the plane concentration of oxygen in the oxygen atomic layer is 6 ⁇ 10 14 atoms/cm 2 or less, defects caused by the oxygen atomic layer can be prevented from being formed in the epitaxial layer, and if the epitaxial layer is polycrystalline. It can prevent it from becoming silicon or amorphous silicon.
  • the planar concentration of oxygen can be measured by SIMS (Secondary Ion Mass Spectrometry).
  • SIMS Secondary Ion Mass Spectrometry
  • a peak is formed at the depth where the oxide layer is formed.
  • the planar concentration can be determined by integrating the product of the volume concentration and depth obtained by one sputtering process near the peak.
  • an epitaxial wafer 10A as shown in FIG. 2, for example, can be obtained.
  • an oxide film is formed on a single crystal silicon wafer 1 as described above, the oxide film is thinned to form an oxygen atomic layer 2, and then single crystal silicon is epitaxially grown. By doing so, a uniform oxygen atomic layer 2 can be formed within the wafer surface. This is because the oxidation rate in single-crystal silicon slows down due to the growth of the oxide film, so the thickness of the oxide film is easier to control than the oxygen atomic layer 2, and the thinning of the oxide film is easier than the oxidation process. This is thought to be because it is easier to control as it progresses slowly.
  • step S15 of epitaxially growing single-crystal silicon repeating step S13 of forming an oxide film, step S14 of forming oxygen atomic layer 2, and step S15 of epitaxially growing single-crystal silicon, for example, as shown in FIG.
  • a plurality of oxygen atomic layers 2 can be formed. That is, according to the method for manufacturing an epitaxial wafer according to this aspect, an epitaxial wafer 10B shown in FIG. 3 is obtained in which oxygen atomic layers 2 and single-crystal epitaxial silicon layers 3 are alternately and repeatedly stacked on a single-crystal silicon wafer 1. be able to.
  • the top surface of the epitaxial wafer 10B in FIG. 3 is a single-crystal epitaxial silicon layer 3.
  • the gettering effect can be enhanced more than when a single oxygen atomic layer 2 is formed.
  • the method for manufacturing an epitaxial wafer of the present invention as described above is a highly versatile method that does not require any special equipment, and also allows stable and simple formation of an oxygen atomic layer for proximity gettering. It is possible to form a high-quality epitaxial layer, and a high-quality epitaxial wafer can be obtained.
  • Example 1 and Comparative Example 1 The conductivity type, diameter, crystal plane orientation, and oxygen concentration of the prepared single crystal silicon wafer are as follows. Wafer conductivity type: p type Diameter: 300mm Crystal plane orientation: (100) Oxygen concentration: 14ppma (JEITA)
  • the single-crystal silicon wafer was subjected to hydrofluoric acid cleaning using a batch-type cleaning apparatus, and then rinsed with pure water.
  • the single crystal silicon wafer was immersed in the SC1 solution using a batch type apparatus.
  • the SC1 solution prepared at this time had a mixing ratio of aqueous ammonia (NH 3 concentration 28%): hydrogen peroxide solution (H 2 O 2 concentration 30%): water of 1:1:10, and the temperature of the solution was 70°C. And so.
  • the immersion time in the SC1 solution was 3 minutes. Thereafter, the single crystal silicon wafer was rinsed with pure water.
  • Example 1 the single crystal silicon wafer with the oxide film formed thereon was transported into an epitaxial growth apparatus.
  • Example 1 the oxide film was thinned by heating in a hydrogen atmosphere to form an oxygen atomic layer.
  • the heating temperature was 700° C.
  • Example 1 the heating time was 20 to 600 seconds.
  • Comparative Example 1 the oxide film was not thinned by heating in a hydrogen atmosphere. That is, the heating time in Comparative Example 1 in a hydrogen atmosphere was 0 seconds.
  • monocrystalline silicon was epitaxially grown using monosilane on the surface of the single-crystal silicon wafer on which the oxygen atomic layer had been formed.
  • the temperature was 700° C.
  • the partial pressure of monosilane was 60 Pa
  • the film thickness was 100 nm.
  • hydrogen was used as the carrier gas. In this way, epitaxial wafers were manufactured in each of Example 1 and Comparative Example 1.
  • Example 1 the formation of the oxygen atomic layer and the epitaxial growth of single crystal silicon were performed in the same chamber.
  • Comparative Example 1 single crystal silicon was epitaxially grown without thinning the oxide film by heating in a hydrogen atmosphere.
  • Example 1 Furthermore, the results of measuring the oxygen concentration within the plane of the substrate when the heating time in Example 1 was 20 seconds are shown by black circles in FIG. From FIG. 5, it can be seen that in Example 1, the oxygen atomic layer could be formed uniformly within the plane.
  • Example 1 As a result of measuring defects with a size of 100 nm or more on the epitaxial wafers manufactured in Example 1 and Comparative Example 1 using SurfScan SP5 manufactured by KLA-Tencor, it was found that the oxide film was thinned by heating in a hydrogen atmosphere. In Comparative Example 1, in which heating was not performed, the number of defects reached the measurement upper limit (approximately 20,000), but in Example 1, in which heating was performed in a hydrogen atmosphere, no defects were present. In the case of , the number was 27 or less, indicating that a single crystal silicon epitaxial layer could be formed on the oxygen atomic layer without generating defects.
  • Comparative Example 2 In Comparative Example 2, first, the same single crystal silicon substrate as in Example 1 and Comparative Example 1 was prepared. Next, in order to remove the natural oxide film from the surface of the prepared single-crystal silicon wafer, the single-crystal silicon wafer was subjected to hydrofluoric acid cleaning using a batch-type cleaning device, followed by deionized water rinsing, and then hydrogen Heated in atmosphere. The heating temperature was 1150° C. and the heating time was 1 minute.
  • Example 2 Under the same conditions as in Example 1 and Comparative Example 1, single crystal silicon was epitaxially grown on the surface of the single crystal silicon wafer on which the oxygen atomic layer was formed. In this manner, an epitaxial wafer was manufactured in Comparative Example 2.
  • Example 1 which is an example of the present invention
  • the oxygen atomic layer is more stable in the epitaxial layer than in Comparative Example 2, in which neither oxide film formation using an oxidizing solution nor thinning of the oxide film was performed.
  • a method for manufacturing an epitaxial wafer in which a single-crystal silicon epitaxial layer is formed on a single-crystal silicon wafer the step of removing a natural oxide film from the surface of the single-crystal silicon wafer; a step of forming an oxide film on the surface of a crystalline silicon wafer using an oxidizing solution; a step of thinning the oxide film to form an oxygen atomic layer after forming the oxide film; and a step of forming an oxygen atomic layer after forming the oxygen atomic layer.
  • a method for manufacturing an epitaxial wafer comprising the step of epitaxially growing single crystal silicon on the surface of the single crystal silicon wafer having the oxygen atomic layer.
  • [5] The method for manufacturing an epitaxial wafer according to [3], characterized in that the ozone water is used as the oxidizing solution, and the temperature of the ozone water is 10°C or more and 30°C or less.
  • [6] The method for producing an epitaxial wafer according to any one of [1] to [5], wherein the oxide film is thinned by heating the single crystal silicon wafer in a hydrogen atmosphere.
  • [7] The method for producing an epitaxial wafer according to [6], wherein the heating temperature in the hydrogen atmosphere is 600°C or higher and 1250°C or lower.

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Abstract

La présente invention concerne un procédé de fabrication d'une tranche épitaxiale dans lequel une couche épitaxiale de silicium monocristallin est formée sur une tranche de silicium monocristallin, le procédé étant caractérisé en ce qu'il comprend : une étape d'élimination d'un film d'oxyde naturel depuis la surface de la tranche de silicium monocristallin ; une étape de formation d'un film d'oxyde sur la surface de la tranche de silicium monocristallin à l'aide d'une solution oxydante après l'étape d'élimination du film d'oxyde naturel ; une étape de formation d'une couche atomique d'oxygène par amincissement du film d'oxyde après formation du film d'oxyde ; et une étape de croissance épitaxiale de silicium monocristallin sur la surface de la tranche de silicium monocristallin ayant la couche atomique d'oxygène après formation de la couche atomique d'oxygène. Ainsi, il est possible de fournir un procédé de fabrication d'une tranche épitaxiale qui peut introduire de manière stable et facile une couche atomique d'oxygène dans une couche épitaxiale et qui peut fabriquer une tranche épitaxiale ayant une couche épitaxiale de silicium monocristallin de haute qualité.
PCT/JP2023/021921 2022-07-06 2023-06-13 Procédé de fabrication de tranche épitaxiale WO2024009705A1 (fr)

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Citations (8)

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Publication number Priority date Publication date Assignee Title
JP2000323689A (ja) * 1999-05-14 2000-11-24 Toshiba Corp 半導体エピタキシャル基板及びその製造方法
JP2009016637A (ja) * 2007-07-06 2009-01-22 Shin Etsu Handotai Co Ltd 半導体基板の製造方法
JP2009289807A (ja) * 2008-05-27 2009-12-10 Hitachi Kokusai Electric Inc 半導体装置の製造方法
JP2014165494A (ja) * 2013-02-22 2014-09-08 Imec 半導体上の酸素単原子層
JP2019004050A (ja) * 2017-06-15 2019-01-10 信越半導体株式会社 エピタキシャルウェーハの製造方法
JP2021111696A (ja) * 2020-01-10 2021-08-02 信越半導体株式会社 エピタキシャルウェーハの製造方法及びエピタキシャルウェーハ
JP2022125625A (ja) * 2021-02-17 2022-08-29 信越半導体株式会社 エピタキシャルウェーハの製造方法
JP2022146664A (ja) * 2021-03-22 2022-10-05 信越半導体株式会社 エピタキシャルウェーハの製造方法

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000323689A (ja) * 1999-05-14 2000-11-24 Toshiba Corp 半導体エピタキシャル基板及びその製造方法
JP2009016637A (ja) * 2007-07-06 2009-01-22 Shin Etsu Handotai Co Ltd 半導体基板の製造方法
JP2009289807A (ja) * 2008-05-27 2009-12-10 Hitachi Kokusai Electric Inc 半導体装置の製造方法
JP2014165494A (ja) * 2013-02-22 2014-09-08 Imec 半導体上の酸素単原子層
JP2019004050A (ja) * 2017-06-15 2019-01-10 信越半導体株式会社 エピタキシャルウェーハの製造方法
JP2021111696A (ja) * 2020-01-10 2021-08-02 信越半導体株式会社 エピタキシャルウェーハの製造方法及びエピタキシャルウェーハ
JP2022125625A (ja) * 2021-02-17 2022-08-29 信越半導体株式会社 エピタキシャルウェーハの製造方法
JP2022146664A (ja) * 2021-03-22 2022-10-05 信越半導体株式会社 エピタキシャルウェーハの製造方法

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