SILICON CARBIDE EPITAXIAL SUBSTRATE AND METHOD OF MANUFACTURING SILICON CARBIDE SEMICONDUCTOR DEVICE

• Main Authors: ITO HIRONORI, HORI TSUTOMU
• Format: Patent
• Language: English; Japanese
• Published: 18.02.2021
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; BASIC ELECTRIC ELEMENTS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; CRYSTAL GROWTH; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SEMICONDUCTOR DEVICES; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

To provide a silicon carbide epitaxial substrate manufactured by a manufacturing process allowing for improvement of in-plane uniformity of thickness of a layer even in epitaxial growth of silicon carbide by a gas-foil system.SOLUTION: A silicon carbide epitaxial substrate 100 has a silicon carbide single crystal substrate 10 and a silicon carbide layer 20. The silicon carbide layer includes a second principal plane 30 on the opposite side from a plane in contact with the silicon carbide single crystal substrate. The second principal plane has an outer circumferential region 32 which is within 5 mm from an outer edge 31, and a center region 33. The silicon carbide layer has a center surface layer 25. The center surface layer has a carrier concentration average value of 1×1014 cm-3 to 5×1016 cm-3. Circumferential uniformity in carrier concentration is 2% or less and in-plane uniformity in carrier concentration is 10% or less. An average value in thickness of a portion 27 of the silicon carbide layer sandwiched between the center region and the silicon carbide single crystal substrate is 5 μm or larger. Circumferential uniformity in thickness is 1% or less and in-plane uniformity in thickness is 4% or less.SELECTED DRAWING: Figure 2 【課題】ガスフォイル方式による炭化珪素のエピタキシャル成長においても層の厚みの面内均一性を向上可能な製法による、炭化珪素エピタキシャル基板の提供。【解決手段】炭化珪素エピタキシャル基板１００は、炭化珪素単結晶基板１０と炭化珪素層２０とを有する。炭化珪素層は、炭化珪素単結晶基板と接する面と反対側の第２主面３０を含む。第２主面は外縁３１から５ｍｍ以内の外周領域３２と中央領域３３とを有する。炭化珪素層は中央表面層２５を有する。中央表面層のキャリア濃度平均値は、１×１０14ｃｍ-3以上５×１０16ｃｍ-3以下である。キャリア濃度の周方向均一性は２％以下であり、かつキャリア濃度の面内均一性は１０％以下である。中央領域と炭化珪素単結晶基板とに挟まれた炭化珪素層の部分２７の厚みの平均値は５μｍ以上である。厚みの周方向均一性は１％以下であり、かつ厚みの面内均一性は４％以下である。【選択図】図２