Abstract: A method of producing a group III nitride such as aluminum nitride, comprising the step of reacting a group III halide gas such as aluminum trichloride gas with a nitrogen source gas such as ammonia gas in a growth chamber to grow a group III nitride on a substrate held in the growth chamber, wherein the method further comprises premixing together the group III halide gas and the nitrogen source gas to obtain a mixed gas and then introducing the mixed gas into the growth chamber without forming a deposit in the mixed gas substantially to be reacted each other. For the growth of a group III nitride such as an aluminum-based group III nitride by HVPE, there are provided a method of producing the group III nitride having as high quality as that obtained by the method of the prior art at a high yield and an apparatus used in the method.

Abstract: The present invention provides a self-supporting substrate obtained by the steps of: forming an Al-based group-III nitride thin-layer having a thickness in the range of 3-200 nm on a base substrate made of a single crystal of an inorganic substance which substantially does not decompose at 800° C. in an inert gas atmosphere and which does produce volatiles by decomposition when contacting with a reducing gas in a temperature range of 800-1600° C., for example sapphire; forming voids along the interface between the base substrate and the Al-based group-III nitride thin-layer of the obtained laminated substrate by thermally treating the laminated substrate in a temperature range of 800-1600° C. in a reducing gas atmosphere containing ammonia gas; forming a group-III nitride single crystal thick-layer on the Al-based group-III nitride thin-layer; and separating these formed layers.

Abstract: According to a cache memory control method of an embodiment, a data write position in a segment of a cache memory is changed to an address to which a lower bit of a logical block address of write data is added as an offset. Then, even if writing is completed within the segment of the cache memory, the remaining regions of the segment is not wasted.

Abstract: The present invention is a method for producing a laminated body, comprising the steps of: (1) preparing a base substrate having a surface formed of a single crystal which is different from the material constituting the Al-based group-III nitride single crystal layer to be formed; (2) forming an Al-based group-III nitride single crystal layer having a thickness of 10 nm to 1.5 ?m on the single crystal surface of the prepared base substrate; (3) forming on the Al-based group-III nitride single crystal layer a non-single crystal layer being 100 times or more thicker than the Al-based group-III nitride single crystal layer without breaking the previously-obtained Al-based group-III nitride single crystal layer; and (4) removing the base substrate.

Abstract: According to one embodiment, a data storage device is provided, which has a cache controller that performs cache control, by using a buffer memory divided into segments, which are managed. The cache controller performs sequential hit judge on each segment, in accordance with the requested access range designated by a read or write command coming from a host system. The cache controller updates the hit upper-limit LBA set for each segment if the result of the hit judge is a mishit.

Abstract: This invention provides a selfsupporting substrate which consists of a n-type conductive aluminum nitride semiconductor crystal and is useful for manufacturing the vertical conductive type AlN semiconductor device. The n-type conductive aluminum nitride semiconductor crystal, by which the selfsupporting substrate is made up, contains Si atom at a concentration of 1×1018 to 5×1020 cm?3, is substantially free from halogen atoms, and substantially does not absorb the light having the energy of not more than 5.9 eV. The selfsupporting substrate can be obtained by a method comprising the steps of forming an AlN crystal layer on a single crystal substrate such as a sapphire by the HVPE method, preheating the obtained substrate having the AlN crystal layer to a temperature of 1,200° C. or more, forming a second layer consisting of the n-type conductive aluminum nitride semiconductor crystal is formed on the AlN crystal layer in high rate by the HVPE method and separating the second layer from the obtained laminate.

Abstract: In a method of manufacturing an aluminum nitride single crystal film on a substrate by heating a sapphire substrate in the presence of carbon, nitrogen and carbon monoxide, an aluminum compound which differs from the raw material sapphire substrate and the formed aluminum nitride single crystal and can control the concentration of aluminum in the heating atmosphere, such as aluminum nitride or alumina, is made existent in a reaction system to promote a reduction nitriding reaction. An aluminum nitride single crystal multi-layer substrate having an aluminum nitride single crystal film on the surface of a sapphire substrate, wherein the aluminum nitride single crystal has improved crystallinity and a low density of defects, is provided.

Abstract: There is provided a method capable of obtaining an aluminum-based group III nitride crystal layer having a smooth surface and high crystallinity by employing only HVPE in which inexpensive raw materials can be used to reduce production costs and high-speed film formation is possible without employing MOVPE. To produce a group III nitride crystal by HVPE comprising the step of growing a group III nitride crystal layer by vapor-phase growth on a single crystal substrate by contacting the heated single crystal substrate with a raw material gas containing a group III halide and a compound having a nitrogen atom, the group III nitride crystal is grown by vapor-phase growth on the single crystal substrate heated at a temperature of 1,000° C. or more and less than 1,200° C. to form an intermediate layer and then, a group III nitride crystal is further grown by vapor-phase growth on the intermediate layer on the substrate heated at a temperature of 1,200° C. or higher.

Abstract: A method of producing a group III nitride such as aluminum nitride, comprising the step of reacting a group III halide gas such as aluminum trichloride gas with a nitrogen source gas such as ammonia gas in a growth chamber to grow a group III nitride on a substrate held in the growth chamber, wherein the method further comprises premixing together the group III halide gas and the nitrogen source gas to obtain a mixed gas and then introducing the mixed gas into the growth chamber without forming a deposit in the mixed gas substantially to be reacted each other. For the growth of a group III nitride such as an aluminum-based group III nitride by HVPE, there are provided a method of producing the group III nitride having as high quality as that obtained by the method of the prior art at a high yield and an apparatus used in the method.

Abstract: An aluminum nitride single-crystal multi-layered substrate comprising an aluminum nitride single-crystal layer formed by direct reduction nitridation on a single-crystal ?-alumina substrate such as a sapphire substrate and an edge-type dislocation layer having a thickness of 10 nm or less in the vicinity of the interface between the both crystals. Threading dislocation is rarely existent in the aluminum nitride single-crystal layer existent on the surface. It is useful as a semiconductor device substrate.

Abstract: A highly crystalline aluminum nitride multi-layered substrate comprising a single-crystal ?-alumina substrate, an aluminum oxynitride layer and a highly crystalline aluminum nitride film as the outermost layer which are formed in the mentioned order, wherein the aluminum oxynitride layer has a threading dislocation density of 6.3×107/cm2 or less and a crystal orientation expressed by the half-value width of its rocking curve of 4,320 arcsec or less; and a production process thereof.

Abstract: An apparatus and method, which can certainly meet access requests and have flexibility, are disclosed. The apparatus includes a unit to be accessed, a slot sequence signal controller which has a plurality of slots, and associates identification information of an access request unit to an arbitrary slot, a request signal holding unit which holds request signals of the access request units, an access request recognition unit which recognizes sequentially and cyclically using identification information in the plurality of slots whether or not the request signal of the access request unit corresponding to the current identification information is held in the request signal holding unit, and an access permission unit which permits access of the corresponding access request unit when the request signal is confirmed.

Abstract: An aluminum nitride single-crystal multi-layered substrate comprising an aluminum nitride single-crystal layer formed by direct reduction nitridation on a single-crystal ?-alumina substrate such as a sapphire substrate and an edge-type dislocation layer having a thickness of 10 nm or less in the vicinity of the interface between the both crystals. Threading dislocation is rarely existent in the aluminum nitride single-crystal layer existent on the surface. It is useful as a semiconductor device substrate.

Abstract: A highly crystalline aluminum nitride multi-layered substrate comprising a single-crystal ?-alumina substrate, an aluminum oxynitride layer and a highly crystalline aluminum nitride film as the outermost layer which are formed in the mentioned order, wherein the aluminum oxynitride layer has a threading dislocation density of 6.3×107/cm2 or less and a crystal orientation expressed by the half-value width of its rocking curve of 4,320 arcsec or less; and a production process thereof.

Abstract: A composite nitride sintered body consisting essentially of aluminum nitride, boron nitride and at least one metal compound selected from the group consisting of compounds of metals of Groups IIa and IIIa of the periodic table.The composite nitride sintered body is produced by intimately mixing a powder of aluminum nitride, a powder of boron nitride and at least one metal compound selected from the group consisting of metal compounds of metals of Groups IIa and IIIa of the periodic table, and sintering the mixture under atmospheric or elevated pressures at a temperature in the range of 1600.degree. to 2400.degree. C.The sintered body has a good machinability.

Abstract: A process for producing basic aluminum sulfate of the general formulaAl(OH).sub.a (SO.sub.4).sub.b.nH.sub.2 Owherein a, b and n are positive numbers satisfying a+2b=3, 2.30.ltoreq.a.ltoreq.2.56, 0.22.ltoreq.b.ltoreq.0.35 and O.ltoreq.n.ltoreq.10, which comprises reacting a water-soluble basic aluminum salt of the general formulaAl(OH).sub.c X.sub.dwherein X represents a monovalent anion, and c and d are positive numbers satisfying c+d=3 and 0.5.ltoreq.c.ltoreq.2.55, with a water-soluble sulfuric acid salt in an aqueous medium at a temperature of less than 90.degree. C. This process gives novel basic aluminum sulfate which is either fibrous, spherical or prismatic depending upon the reaction conditions.