Abstract: A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m·K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/mm or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

Abstract: A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m·K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/mm or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

Abstract: A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m·K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/rum or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

Abstract: A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m·K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/rum or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

Abstract: A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m·K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/mm or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

Abstract: A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m·K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/mm or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

Abstract: There is provided a polycrystalline aluminum nitride substrate that is effective in growing a GaN crystal. The polycrystalline aluminum nitride base material for use as a substrate material for grain growth of GAN-base semiconductors, contains 1 to 10% by weight of a sintering aid component and has a thermal conductivity of not less than 150 W/m·K, the substrate having a surface free from recesses having a maximum diameter of more than 200 ?m.

Abstract: An electronic component module has a circuit board in which metal plates are bonded to both surfaces of a ceramic substrate, and an electronic component that is bonded to at least one surface of the metal plate and is operable at least 125° C. The electronic component is bonded to the metal plate via a brazing material layer having a higher melting point than a operating temperature of the electronic component.

Abstract: A ceramic-metal composite includes a ceramic substrate, an active metal brazing alloy layer, and a metal plate bonded to the ceramic substrate through the active metal brazing alloy layer disposed therebetween. The active metal brazing alloy layer contains a transition metal that is at least one element selected from Group-8 elements specified in the periodic table. According to the above configuration, the following composite and device can be provided: the ceramic-metal composite that exhibits high bonding strength, heat cycle resistance, durability, and reliability even if the ceramic-metal composite is used in a power module and a semiconductor device including the ceramic-metal composite.

Abstract: There is provided a polycrystalline aluminum nitride substrate that is effective in growing a GaN crystal. The polycrystalline aluminum nitride base material for use as a substrate material for grain growth of GAN-base semiconductors, contains 1 to 10% by weight of a sintering aid component and has a thermal conductivity of not less than 150 W/m·K, the substrate having a surface free from recesses having a maximum diameter of more than 200 ?m.

Abstract: An electronic component module 1 has a circuit board 2 in which metal plates 5 and 7 are bonded to both surfaces of a ceramic substrate 3, and an electronic component 9 that is bonded to at least one surface of the metal plate 5 and is operable at least 125° C. The electronic component 9 is bonded to the metal plate 5 via a brazing material layer 8 having a higher melting point than a operating temperature of the electronic component 9.

Abstract: An electronic component module 1 has a circuit board 2 in which metal plates 5 and 7 are bonded to both surfaces of a ceramic substrate 3, and an electronic component 9 that is bonded to at least one surface of the metal plate 5 and is operable at least 125° C. The electronic component 9 is bonded to the metal plate 5 via a brazing material layer 8 having a higher melting point than a operating temperature of the electronic component 9.

Abstract: Problem is to provide a ceramic-metal composite and a semiconductor device that exhibits high bonding strength, heat cycle resistance, durability, and reliability even if the ceramic-metal composite is used in a power module. A ceramic-metal composite includes a ceramic substrate, an active metal brazing alloy layer, and a metal plate bonded to the ceramic substrate through the active metal brazing alloy layer disposed therebetween. The active metal brazing alloy layer contains a transition metal.

Abstract: In the production of a ceramic substrate (1) with a level difference (3), a surface of a fired substrate obtained by firing of a ceramic green sheet is honed to form the level difference (3). Alternatively, a level difference is first formed through processing of a ceramic green sheet, laminating of a ceramic green sheet, or the like, and thereafter the ceramic green sheet is fired to obtain a fired substrate (ceramic substrate) (1) with a level difference (3).

Abstract: An electronic component module 1 has a circuit board 2 in which metal plates 5 and 7 are bonded to both surfaces of a ceramic substrate 3, and an electronic component 9 that is bonded to at least one surface of the metal plate 5 and is operable at least 125° C. The electronic component 9 is bonded to the metal plate 5 via a brazing material layer 8 having a higher melting point than a operating temperature of the electronic component 9.

Abstract: An aluminum nitride substrate includes an aluminum nitride sintered body containing a rare earth oxide as a sintering additive component. In the aluminum nitride substrate, a surface thereof is machined so that arithmetic average roughness Ra is 0.5 &mgr;m or less; an aggregate size of the sintering additive component present on the machined surface is 20 &mgr;m or less; and a total aggregate area in a unit area of the machined surface is 5% or less. A metal thin film is deposited on such machined surface with good intimate contact properties, and furthermore deposition accuracy or the like is improved.

Abstract: An aluminum nitride substrate includes an aluminum nitride sintered body containing a rare earth oxide as a sintering additive component. In the aluminum nitride substrate, a surface thereof is machined so that arithmetic average roughness Ra is 0.5 &mgr;m or less; an aggregate size of the sintering additive component present on the machined surface is 20 &mgr;m or less; and a total aggregate area in a unit area of the machined surface is 5% or less. A metal thin film is deposited on such machined surface with good intimate contact properties, and furthermore deposition accuracy or the like is improved.

Abstract: The present invention provides a ceramic circuit board comprising: a ceramic substrate and a metal circuit plate bonded to the ceramic substrate through a brazing material layer; wherein the brazing material layer is composed of Al—Si group brazing material and an amount of Si contained in the brazing material is 7 wt % or less. In addition, it is preferable to form a thinned portion, holes, or grooves to outer peripheral portion of the metal circuit plate. According to the above structure of the present invention, there can be provided a ceramic circuit board having both high bonding strength and high heat-cycle resistance, and capable of increasing an operating reliability as electronic device.

Abstract: A photo-decoloring dye represented by the following Formula (1), ##STR1## wherein Z.sub.1, Z.sub.2 and Z.sub.3 each represents a carbon atom or a nitrogen atom, R.sub.1, R.sub.2 and R.sub.3 each represents a hydrogen atom and substituents, Z.sub.2 and Z.sub.3 may form a condensed ring, Z represents N or CH, X+ represents an organic cation, m represents an integer of 0 to 4, n represents an integer of 0 to 3.

Abstract: A method to recover the resources incorporated in a photographic material is disclosed. An exposed silver salt light-sensitive photographic material is subjected to color development processing; the obtained image information is optically read; digital image information is obtained by converting the read information to electrical signals, and the resulting image information is recorded on a recording medium, and resources incorporated in a photographic material is recovered from the processed photographic material.