Abstract: A growing method of a group III nitride semiconductor crystal includes the steps of preparing an underlying substrate, and growing a group III nitride semiconductor crystal doped with silicon by using silicon tetrafluoride gas as doping gas, on the underlying substrate by vapor phase growth.

Abstract: A growing method of a group III nitride semiconductor crystal includes the steps of preparing an underlying substrate, and growing a first group III nitride semiconductor crystal doped with silicon by using silicon tetrachloride (SiCl4) gas as doping gas, on the underlying substrate by vapor phase growth. The growth rate of the first group III nitride semiconductor crystal is at least 200 ?m/h and not more than 2000 ?m/h.

Abstract: A group III nitride semiconductor crystal substrate has a diameter of at least 25 mm and not more than 160 mm. The resistivity of the group III nitride semiconductor crystal substrate is at least 1×10?4 ?·m and not more than 0.1 ?·cm. The resistivity distribution in the diameter direction of the group III nitride semiconductor crystal is at least ?30% and not more than 30%. The resistivity distribution in the thickness direction of the group III nitride semiconductor crystal is at least ?16% and not more than 16%.

Abstract: An AlxGayIn1-x-yN substrate in which particles having a grain size of at least 0.2 ?m on a surface of the AlxGayIn1-x-yN substrate are at most 20 in number when a diameter of the AlxGayIn1-x-yN substrate is two inches, and a cleaning method with which the AlxGayIn1-x-yN substrate can be obtained are provided. Further, an AlxGayIn1-x-yN substrate in which, in a photoelectron spectrum of a surface of the AlxGayIn1-x-yN substrate by X-ray photoelectron spectroscopy with a detection angle of 10°, a ratio between a peak area of C1s electrons and a peak area of N1s electrons (C1s electron peak area/N1s electron peak area) is at most 3, and a cleaning method with which the AlxGayIn1-x-yN substrate can be obtained are provided.

Abstract: The present invention provides a method of cleaning a GaAs substrate with less precipitate particles after cleaning. This cleaning method comprises an acid cleaning step (S11), a deionized water rinsing step (S12), and a rotary drying step (S13). First, a GaAs substrate with a mirror finished surface is immersed in an acid cleaning solution in the acid cleaning step (S11). In the acid cleaning step, the cleaning time is less than 30 seconds. Next, the deionized water rinsing step performs the cleaned GaAs substrate with deionized water (S12) to wash away the cleaning solution deposited thereon. Subsequently, the rotary drying step dries the GaAs substrate deposited on deionized water (S13). This provides the cleaned GaAs substrate with less precipitate particles.

Abstract: Affords methods of surface treating a substrate and of manufacturing Group III-V compound semiconductors, in which a substrate made of a Group III-V semiconductor compound is rendered stoichiometric, and microscopic roughness on the surface following epitaxial growth is reduced. The methods include preparing a substrate made of a Group III-V semiconductor compound (S10), and cleaning the substrate with a cleaning solution whose pH has been adjusted to an acidity of 2 to 6.3 inclusive, and to which an oxidizing agent has been added (S20).

Abstract: An AlxGayIn1-x-yN substrate in which particles having a grain size of at least 0.2 ?m on a surface of the AlxGayIn1-x-yN substrate are at most 20 in number when a diameter of the AlxGayIn1-x-yN substrate is two inches, and a cleaning method with which the AlxGayIn1-x-yN substrate can be obtained are provided. Further, an AlxGayIn1-x-yN substrate in which, in a photoelectron spectrum of a surface of the AlxGayIn1-x-yN substrate by X-ray photoelectron spectroscopy with a detection angle of 10°, a ratio between a peak area of C1s electrons and a peak area of N1s electrons (C1s electron peak area/N1s electron peak area) is at most 3, and a cleaning method with which the AlxGayIn1-x-yN substrate can be obtained are provided.

Abstract: Affords methods of surface treating a substrate and of manufacturing Group III-V compound semiconductors, in which a substrate made of a Group III-V semiconductor compound is rendered stoichiometric, and microscopic roughness on the surface following epitaxial growth is reduced. The methods include preparing a substrate made of a Group III-V semiconductor compound (S10), and cleaning the substrate with a cleaning solution whose pH has been adjusted to an acidity of 2 to 6.3 inclusive, and to which an oxidizing agent has been added (S20).

Abstract: An AlxGayIn1-x-yN substrate in which particles having a grain size of at least 0.2 ?m on a surface of the AlxGayIn1-x-yN substrate are at most 20 in number when a diameter of the AlxGayIn1-x-yN substrate is two inches, and a cleaning method with which the AlxGayIn1-x-yN substrate can be obtained are provided. Further, an AlxGayIn1-x-yN substrate in which, in a photoelectron spectrum of a surface of the AlxGayIn1-x-yN substrate by X-ray photoelectron spectroscopy with a detection angle of 10°, a ratio between a peak area of C1s electrons and a peak area of N1s electrons (C1s electron peak area/N1s electron peak area) is at most 3, and a cleaning method with which the AlxGayIn1-x-yN substrate can be obtained are provided.

Abstract: A method for separating chips from a diamond wafer comprising a substrate, a chemically vapor-deposited diamond layer, and microelectronic elements, with the microelectronic elements protected from thermal damage and degradation caused by the thermally decomposed cuttings produced during the processing steps. (1) Front-side grooves 6 are formed on the chemically vapor-deposited diamond layer 2 by laser processing using a laser such as a YAG, CO2, or excimer laser each having a large output so that the grooves 6 can have a depth 1/100 to 1.5 times the thickness of the diamond layer. (2) The thermally decomposed cuttings produced during the laser processing are removed by using a plasma. (3) Back-side grooves 9 are formed on the substrate 1 by dicing such that the back-side grooves 9 are in alignment with the front-side grooves 6. (4) The diamond wafer 4 is divided into individual chips 10 by applying mechanical stresses.

Abstract: A high-purity naphthalenedicarboxylic acid is produced by a method including Steps [1] and [2]: In Step [I], a raw mixture of crude terephthalic acid and crude naphthalenedicarboxylic acid is dissolved into high-temperature high-pressure water to form a dibasic acid solution wherein the crude naphthalenedicarboxylic acid content is 0.1 to 10 mass percent of the crude terephthalic acid content, the dibasic acid solution is brought into contact with hydrogen in the presence of a catalyst. In Step [II], the resultant in the dibasic acid solution is crystallized by multiple stages while the temperature and the pressure are reduced for each stage, and acid mixtures containing enriched naphthalenedicarboxylic acid or enriched terephthalic acid are obtained by solid-liquid separation.

Abstract: A diamond film is deposited in the thickness of 20 &mgr;m on a silicon wafer 0.8 mm thick by filament CVD. Here the hydrogen content of the diamond film is adjusted in the range of not less than 1% nor more than 5% in atomic percent. By mechanical polishing with a grinding wheel including diamond abrasives, the diamond film is smoothed so that the arithmetic mean roughness (Ra) of the surface thereof becomes not more than 20 nm.

Abstract: A diamond film is deposited in the thickness of 20 &mgr;m on a silicon wafer 0.8 mm thick by filament CVD Here the hydrogen content of the diamond film is adjusted in the range of not less than 1% nor more than 5% in atomic percent. By mechanical polishing with a grinding wheel including diamond abrasives, the diamond film is smoothed so that the arithmetic mean roughness (Ra) of the surface thereof becomes not more than 20 nm.

Abstract: A method for separating chips from a diamond wafer comprising a substrate, a chemically vapor-deposited diamond layer, and microelectronic elements, with the microelectronic elements protected from thermal damage and degradation caused by the thermally decomposed cuttings produced during the processing steps. (1) Front-side grooves 6 are formed on the chemically vapor-deposited diamond layer 2 by laser processing using a laser such as a YAG, CO2, or excimer laser each having a large output so that the grooves 6 can have a depth 1/100 to 1.5 times the thickness of the diamond layer. (2) The thermally decomposed cuttings produced during the laser processing are removed by using a plasma. (3) Back-side grooves 9 are formed on the substrate 1 by dicing such that the back-side grooves 9 are in alignment with the front-side grooves 6. (4) The diamond wafer 4 is divided into individual chips 10 by applying mechanical stresses.

Abstract: A high-purity naphthalenedicarboxylic acid is produced by a method including Steps [1] and [2]: In Step [I], a raw mixture of crude terephthalic acid and crude naphthalenedicarboxylic acid is dissolved into high-temperature high-pressure water to form a dibasic acid solution wherein the crude naphthalenedicarboxylic acid content is 0.1 to 10 mass percent of the crude terephthalic acid content, the dibasic acid solution is brought into contact with hydrogen in the presence of a catalyst. In Step [II], the resultant in the dibasic acid solution is crystallized by multiple stages while the temperature and the pressure are reduced for each stage, and acid mixtures containing enriched naphthalenedicarboxylic acid or enriched terephthalic acid are obtained by solid-liquid separation.

Abstract: The present invention provides a method for manufacturing a highly pure 2,6-dimethylnaphthalene having a purity of 99% or more even when a mixture of dimethylnaphthalene isomers containing 5 wt % or more of 2,7-dimethylnaphthalate is used as a feedstock. The method for manufacturing 2,6-dimethylnaphthalene comprises a step of performing crystallization and solid-liquid separation of a liquid primarily containing dimethylnaphthalene isomers so that the liquid is separated into a cake containing the dimethylnaphthalene isomers and a mother liquor, and a step of performing separation/purification of the cake. In the method described above, the crystallization and the solid-liquid separation are performed under the condition in which the ratio of the content of 2,6-dimethylnaphthalene in the mother liquor to that of 2,7-dimethylnaphthalene therein is not less than 1 so that the content of 2,6-dimethylnaphthalene in the cake is 60% or more and that the content of 2,7-dimethylnaphthalene therein is 6.5% or less.

Abstract: The invention offers a hard carbon film and a SAW substrate that are easy to fabricate or low in manufacturing cost while virtually maintaining the quality that affects the important properties of a device that comprises the hard carbon film or the SAW substrate. The hard carbon film comprises a composite film of graphite-like diamond and carbon clusters; the composite film has a continuous crystal structure.

Abstract: The invention offers a hard carbon film and a SAW substrate that are easy to fabricate or low in manufacturing cost while virtually maintaining the quality that affects the important properties of a device that comprises the hard carbon film or the SAW substrate. The hard carbon film comprises a composite film of graphite-like diamond and carbon clusters; the composite film has a continuous crystal structure.

Abstract: The present invention provides a method for manufacturing a highly pure 2,6-dimethylnaphthalene having a purity of 99% or more even when a mixture of dimethylnaphthalene isomers containing 5 wt % or more of 2,7-dimethylnaphthalate is used as a feedstock. The method for manufacturing 2,6-dimethylnaphthalene comprises a step of performing crystallization and solid-liquid separation of a liquid primarily containing dimethylnaphthalene isomers so that the liquid is separated into a cake containing the dimethylnaphthalene isomers and a mother liquor, and a step of performing separation/purification of the cake. In the method described above, the crystallization and the solid-liquid separation are performed under the condition in which the ratio of the content of 2,6-dimethylnaphthalene in the mother liquor to that of 2,7-dimethylnaphthalene therein is not less than 1 so that the content of 2,6-dimethylnaphthalene in the cake is 60% or more and that the content of 2,7-dimethylnaphthalene therein is 6.5% or less.