Abstract: Provided is an alumina ceramic with a low secondary electron emission coefficient and suitable for components of a high frequency generator, a plasma generator and so on. The alumina ceramic contains alumina as a main component, and at least two kinds of elements selected from an alkaline earth metal and from an element belonging to period 3, 4 or 5. The alkaline earth metal and the element belonging to period 3, 4 or 5 have a higher first ionization energy than aluminum. An electronegativity difference between the alkaline earth metal and the element belonging to period 3, 4 or 5 is 0 or more and 0.6 or less. A ratio (x/y) of the grain boundary area (x) to the grain area (y) in the alumina ceramic is 0.0001 to 0.001.

Abstract: The present invention relates to an alumina sintered body and a manufacturing method therefor; for example, the present invention relates to an alumina sintered body that is suitably utilized for a member or similar used in a plasma processing device, an etcher for semiconductor/liquid crystal display device manufacturing, a CVD device, or similar, or that is suitably utilized for a substrate or similar of a plasma-resistant member which is to be coated, as well as a manufacturing method for said alumina sintered body.

Abstract: An alumina sintered body having a low dielectric loss tangent and a method for manufacturing the alumina sintered body are provided. An alumina sintered body contains Al2O3 99.50 mass % or more, and 99.95 mass % or less and sodium and silicon, wherein at a surface layer A in any given cross-section and a central portion B of the cross-section in a depth direction from the surface layer A, a concentration ratio of sodium to silicon in the surface layer A is smaller than the concentration ratio of sodium to silicon at the central portion B.

Abstract: The present invention provides a nitride semiconductor substrate suitable for a high frequency device. The nitride semiconductor substrate has a substrate, a buffer layer made of group 13 nitride semiconductors, and an active layer made of group 13 nitride semiconductors in this order, wherein the substrate is composed of a first substrate made of polycrystalline aluminum nitride, and a second substrate made of Si single crystal having a specific resistance of 100 ?·cm or more, formed on the first substrate, the average particle size of AlN constituting the first substrate is 3 to 9 ?m, and preferably, the second substrate grown by the MCZ method has an oxygen concentration of 1E+18 to 9E+18 atoms/cm3 and a specific resistance of 100 to 1000 ?·cm.

Abstract: A gas nozzle having a fired surface excellent in particle reduction effect is provided. The gas nozzle 1 is a columnar gas nozzle made of sintered ceramics, provided with at least one through-hole 2 through which gas flows. The entire inner surface 2a of the through-hole 2 and the end face 1A on which outlet 2b of the through-hole 2 is provided are both fired surfaces. The inner surface 2a of the through-hole 2 has a first region A in the vicinity of the outlet 2b and a second region B which is located at a further position than the first region A. The average crystal grain size in the first region A is formed to be smaller than the average crystal grain size in the second region B.

Abstract: The present invention relates to a phosphor plate including a sintered body including (Y1-x-y, Gdx, Cey)3Al5O12 particles and Al2O3 particles, in which 0.07?x?0.11 and 0.010?y?0.015 are satisfied, the (Y1-x-y, Gdx, Cey)3Al5O12 particles in the sintered body has an average particle diameter of 4 ?m or more and 6 ?m or less, the (Y1-x-y, Gdx, Cey)3Al5O12 particles has a concentration of 20 vol % or more and 30 vol % or less with respect to a total amount 100 vol % of the (Y1-x-y, Gdx, Cey)3Al5O12 particles and the Al2O3 particles, a ratio of an average particle diameter of the Al2O3 particles to the average particle diameter of the (Y1-x-y, Gdx, Cey)3Al5O12 particles is 1 or more and 2 or less, and the sintered body has a total thickness of 150 ?m or more and 250 ?m or less.

Abstract: Provided is an alumina ceramic with a low secondary electron emission coefficient and suitable for components of a high frequency generator, a plasma generator and so on. The alumina ceramic contains alumina as a main component, and at least two kinds of elements selected from an alkaline earth metal and from an element belonging to period 3, 4 or 5. The alkaline earth metal and the element belonging to period 3, 4 or 5 have a higher first ionization energy than aluminum. An electronegativity difference between the alkaline earth metal and the element belonging to period 3, 4 or 5 is 0 or more and 0.6 or less. A ratio (x/y) of the grain boundary area (x) to the grain area (y) in the alumina ceramic is 0.0001 to 0.001.

Abstract: A diffuser includes a diffuser element made of silicon carbide having conductivity, conductive holding members for holding the diffuser element, conductive gaskets that seal between the diffuser element and the holding members. Static electricity on the diffuser element is eliminated through the gaskets, and the holding members.

Abstract: The present invention relates to a silica-glass crucible for pulling up single-crystal silicon therefrom by Czochralski method (CZ method) or for melting an optical-glass, which includes a crystallization promoter, and method of producing the silica-glass crucible in which a raw-material silica powder including Al and Ca at a specific molar concentration ratio is molded.

Abstract: The characteristic of Fe-doped HEMTs is improved. The invention provides a nitride semiconductor substrate having a substrate, a buffer layer made of nitride semiconductors on the substrate, and an active layer composed of nitride semiconductor layers on the buffer layer; the buffer layer containing Fe, the Fe having a concentration profile in which the Fe concentration increases monotonically and gradually in the thickness direction of the buffer layer from an interface between the substrate and the buffer layer, has a maximum value within 2×1017 to 1.1×1020 atoms/cm3 inclusive, and decreases monotonically and gradually toward an interface between the buffer layer and the active layer, and the point of the maximum value being within ±50 nm from the midpoint in the thickness direction of the buffer layer, and being 500 nm or more away from the interface between the buffer layer and the active layer.

Abstract: The present invention relates to a glass member in which an inorganic phosphor is dispersed in a glass matrix, in which the glass member includes an SiO2—B2O3 based glass as the glass matrix, and the SiO2—B2O3 based glass includes SiO2 as a main component thereof, and includes, based on a total amount of the SiO2—B2O3 based glass: Al2O3 in an amount of 4 to 10 wt %; and MgO and ZnO in a total amount of 0.1 to 0.7 wt %.

Abstract: The present invention provides a nitride semiconductor substrate suitable for a high frequency device. The nitride semiconductor substrate has a substrate, a buffer layer made of group 13 nitride semiconductors, and an active layer made of group 13 nitride semiconductors in this order, wherein the substrate is composed of a first substrate made of polycrystalline aluminum nitride, and a second substrate made of Si single crystal having a specific resistance of 100 ?·cm or more, formed on the first substrate, the average particle size of AlN constituting the first substrate is 3 to 9 ?m, and preferably, the second substrate grown by the MCZ method has an oxygen concentration of 1E+18 to 9E+18 atoms/cm3 and a specific resistance of 100 to 1000 ?·cm.

Abstract: A silicon carbide porous body includes a skeletal structure formed by a plurality of silicon carbide particles bonded to each other, a plurality of pores formed by the skeletal structure, neck parts formed by surface-contacting of adjacent silicon carbide particles, and an average pore size is larger than 3 ?m and equal to or smaller than 9 ?m, and a porosity ranges from 35% to 55%. A break filter using the silicon carbide porous body enables high performance of collection of particles, prevention of soaring up of particles, and shortening of a restoration time from the depressurized state of the chamber to the atmospheric state.

Abstract: The present invention relates to a silica glass member including: a main body including a silica glass and having a bonding part for bonding to another member; and a bonding film which is provided on the bonding part, has a thickness of 0.2 ?m to 10 ?m, and includes Au and a glass formed through melting of glass frit, in which the bonding film is produced from Au powder having an average particle diameter of 3 ?m or less and glass frit having a softening point of 850° C. or lower, a process for producing a silica glass member, and a process for bonding a ceramic and a silica glass.

Abstract: The characteristic of Fe-doped HEMTs is improved. The invention provides a nitride semiconductor substrate having a substrate, a buffer layer made of nitride semiconductors on the substrate, and an active layer composed of nitride semiconductor layers on the buffer layer; the buffer layer containing Fe, the Fe having a concentration profile in which the Fe concentration increases monotonically and gradually in the thickness direction of the buffer layer from an interface between the substrate and the buffer layer, has a maximum value within 2×1017 to 1.1×1020 atoms/cm3 inclusive, and decreases monotonically and gradually toward an interface between the buffer layer and the active layer, and the point of the maximum value being within ±50 nm from the midpoint in the thickness direction of the buffer layer, and being 500 nm or more away from the interface between the buffer layer and the active layer.

Abstract: A diffuser includes a diffuser element made of silicon carbide having conductivity, conductive holding members for holding the diffuser element, conductive gaskets that seal between the diffuser element and the holding members. Static electricity on the diffuser element is eliminated through the gaskets, and the holding members.

Abstract: The present invention relates to a short carbon fiber-reinforced composite material, including a base material part and at least one sliding part contacting the base material part, in which each of the base material part and the sliding part has a plurality of short carbon fiber bundles in which at least a part thereof has been converted into SiC and a SiC matrix present among the plurality of short carbon fiber bundles, as constituent components, and the short carbon fiber bundles of the sliding part have a SiC conversion higher than that of the short carbon fiber bundles of the base material part.

Abstract: A nitride semiconductor substrate can effectively reduce leakage current in the vertical direction. The nitride semiconductor substrate comprises a buffer layer and an operation layer, both of which are made of nitride semiconductor, deposited on a silicon single crystal substrate, wherein the buffer layer comprises a single-layered first initial layer in contact with the silicon single crystal layer, and a single-layered second initial layer in contact with the first initial layer, the first initial layer is made of AlN, the second initial layer is made of AlzGa1-zN (0.12?z?0.65), and in an X-Y graph where the X-axis denotes z×100 and the Y-axis denotes carbon concentration in the second initial layer, X ranges from 12 to 65 and Y is within a range between Y=1E+17×exp(?0.05×X) and Y=1E+21×exp(?0.05×X).

Abstract: A nitride semiconductor substrate can effectively reduce leakage current in the vertical direction. The nitride semiconductor substrate comprises a buffer layer and an operation layer, both of which are made of nitride semiconductor, deposited on a silicon single crystal substrate, wherein the buffer layer comprises a single-layered first initial layer in contact with the silicon single crystal layer, and a single-layered second initial layer in contact with the first initial layer, the first initial layer is made of AlN, the second initial layer is made of AlzGa1-zN (0.12?z?0.65), and in an X-Y graph where the X-axis denotes z×100 and the Y-axis denotes carbon concentration in the second initial layer, X ranges from 12 to 65 and Y is within a range between Y=1E+17×exp(?0.05×X) and Y=1E+21×exp(?0.05×X).

Abstract: Provided is a nitride semiconductor structure capable of preventing deterioration of transistor characteristics caused by diffusion of a P-type conductive element by using an extremely simple configuration, instead of introducing a diffusion suppression layer. A nitride semiconductor substrate comprises at least a layered structure made of group 13 nitride semiconductors, wherein a first layer, a second layer having a wider band gap than the first layer, and a third layer containing a P-type conductive impurity at a concentration of 5E+18 atoms/cc or more are stacked in this order in the layered structure, and a maximum concentration of P-type conductive impurity in the first layer is 10% or less of the concentration of P-type conductive impurity in the third layer.