Abstract: A gallium arsenide single crystal substrate having a main surface, in which a ratio of the number of As atoms existing as diarenic trioxide to the number of As atoms existing as diarsenic pentoxide is greater than or equal to 2 when the main surface is measured by X-ray photoelectron spectroscopy, in which an X-ray having energy of 150 eV is used and a take-off angle of a photoelectron is set to 5°. Arithmetic average roughness (Ra) of the main surface is less than or equal to 0.3 nm.

Abstract: A gallium arsenide single crystal substrate having a main surface, in which a ratio of the number of As atoms existing as diarsenic trioxide to the number of As atoms existing as diarsenic pentoxide is greater than or equal to 2 when the main surface is measured by X-ray photoelectron spectroscopy, in which an X-ray having energy of 150 eV is used and a take-off angle of a photoelectron is set to 5°. Arithmetic average roughness (Ra) of the main surface is less than or equal to 0.3 nm.

Abstract: Provided are a group III nitride composite substrate having a low sheet resistance and produced with a high yield, and a method for manufacturing the same, as well as a method for manufacturing a group III nitride semiconductor device using the group III nitride composite substrate. A group III nitride composite substrate includes a group III nitride film and a support substrate formed from a material different in chemical composition from the group III nitride film. The group III nitride film is joined to the support substrate in one of a direct manner and an indirect manner. The group III nitride film has a thickness of 10 ?m or more. A sheet resistance of a group III-nitride-film-side main surface is 200 ?/sq or less.

Abstract: Provided are a group III nitride composite substrate having a low sheet resistance and produced with a high yield, and a method for manufacturing the same, as well as a method for manufacturing a group III nitride semiconductor device using the group III nitride composite substrate. A group III nitride composite substrate includes a group III nitride film and a support substrate formed from a material different in chemical composition from the group III nitride film. The group III nitride film is joined to the support substrate in one of a direct manner and an indirect manner. The group III nitride film has a thickness of 10 ?m or more. A sheet resistance of a group III-nitride-film-side main surface is 200 ?/sq or less.

Abstract: Provided are a group III nitride composite substrate having a low sheet resistance and produced with a high yield, and a method for manufacturing the same, as well as a method for manufacturing a group III nitride semiconductor device using the group III nitride composite substrate. A group III nitride composite substrate includes a group III nitride film and a support substrate formed from a material different in chemical composition from the group III nitride film. The group III nitride film is joined to the support substrate in one of a direct manner and an indirect manner. The group III nitride film has a thickness of 10 ?m or more. A sheet resistance of a group III-nitride-film-side main surface is 200 ?/sq or less.

Abstract: Provided are a group III nitride composite substrate having a low sheet resistance and produced with a high yield, and a method for manufacturing the same, as well as a method for manufacturing a group III nitride semiconductor device using the group III nitride composite substrate. A group III nitride composite substrate includes a group III nitride film and a support substrate formed from a material different in chemical composition from the group III nitride film. The group III nitride film is joined to the support substrate in one of a direct manner and an indirect manner. The group III nitride film has a thickness of 10 ?m or more. A sheet resistance of a group III-nitride-film-side main surface is 200 ?/sq or less.

Abstract: A group III nitride composite substrate with a diameter of 75 mm or more includes a support substrate and a group III nitride film with a thickness of 50 nm or more and less than 10 ?m that are bonded to each other. A ratio st/mt of a standard deviation st of the thickness of the group III nitride film to a mean value mt of the thickness thereof is 0.01 or more and 0.5 or less, and a ratio so/mo of a standard deviation so of an absolute value of an off angle between a main surface of the group III nitride film and a plane of a predetermined plane orientation to a mean value mo of the absolute value of the off angle is 0.005 or more and 0.6 or less.

Abstract: Provided are a group III nitride composite substrate having a low sheet resistance and produced with a high yield, and a method for manufacturing the same, as well as a method for manufacturing a group III nitride semiconductor device using the group III nitride composite substrate. A group III nitride composite substrate includes a group III nitride film and a support substrate formed from a material different in chemical composition from the group III nitride film. The group III nitride film is joined to the support substrate in one of a direct manner and an indirect manner. The group III nitride film has a thickness of 10 ?m or more. A sheet resistance of a group III-nitride-film-side main surface is 200 ?/sq or less.

Abstract: Group III nitride crystal produced by cutting, from III nitride bulk crystal, a plurality of Group III nitride crystal substrates with major-surface plane orientation misoriented five degrees or less with respect to a crystal-geometrically equivalent plane orientation selected from the group consisting of {20-21}, {20-2-1}, {22-41}, and {22-4-1}, transversely arranging the substrates adjacent to each other such that their major surfaces are parallel to each other and such that their [0001] directions coincide with each other, and growing a Group III nitride crystal on the major surfaces. The Group III nitride crystal substrates are further characterized by satisfying at least either an oxygen-atom concentration of 1×1016 cm?3 to 4×1019 cm?3 or a silicon-atom concentration of 6×1014 cm?3 to 5×1018 cm?3, and by having a carrier concentration of 1×1016 cm?3 to 6×1019 cm?3.

Abstract: Affords a method of growing, across the entirety of a major surface of a first III-nitride crystal, a second III-nitride crystal by HVPE, in an ambient temperature higher than 1100° C. The present III-nitride crystal growth method comprises: a step of preparing a first III-nitride crystal (10) having an alkali-metal atom concentration of less than 1.0×1018 cm?3; and a step of growing a second III-nitride crystal (20) onto a major surface (10m) of the first III-nitride crystal (10) by HVPE, in an ambient temperature higher than 1100° C.

Abstract: A group III nitride composite substrate with a diameter of 75 mm or more includes a support substrate and a group III nitride film with a thickness of 50 nm or more and less than 10 ?m that are bonded to each other. A ratio st/mt of a standard deviation st of the thickness of the group III nitride film to a mean value mt of the thickness thereof is 0.01 or more and 0.5 or less, and a ratio so/mo of a standard deviation so of an absolute value of an off angle between a main surface of the group III nitride film and a plane of a predetermined plane orientation to a mean value mo of the absolute value of the off angle is 0.005 or more and 0.6 or less.

Abstract: A composite base of the present invention includes a sintered base and a base surface flattening layer disposed on the sintered base, and the base surface flattening layer has a surface RMS roughness of not more than 1.0 nm. A composite substrate of the present invention includes the composite base and a semiconductor crystal layer disposed on a side of the composite base where the base surface flattening layer is located, and a difference between a thermal expansion coefficient of the sintered base and a thermal expansion coefficient of the semiconductor crystal layer is not more than 4.5×10?6K?1. Thereby, a composite substrate in which a semiconductor crystal layer is attached to a sintered base, and a composite base suitably used for that composite substrate are provided.

Abstract: A GaN-crystal free-standing substrate obtained from a GaN crystal grown by HVPE with a (0001) plane serving as a crystal growth plane and at least one plane of a {10-11} plane and a {11-22} plane serving as a crystal growth plane that constitutes a facet crystal region, except for the side surface of the crystal, wherein the (0001)-plane-growth crystal region has a carbon concentration of 5×1016 atoms/cm3 or less, a silicon concentration of 5×1017 atoms/cm3 or more and 2×1018 atoms/cm3 or less, and an oxygen concentration of 1×1017 atoms/cm3 or less; and the facet crystal region has a carbon concentration of 3×1016 atoms/cm3 or less, a silicon concentration of 5×1017 atoms/cm3 or less, and an oxygen concentration of 5×1017 atoms/cm3 or more and 5×1018 atoms/cm3 or less.

Abstract: A traction control device of a six-wheel drive construction machine, the drive construction machine including: right and left front wheels connected to each other via an axle, right and left center wheels connected to each other via an axle, and right and left rear wheels connected to each other via an axle, the right and left front, center and rear wheels being driven as driving wheels; a braking mechanism provided to each of the wheels; and a differential adjusting mechanism for adjusting a differential between the front and rear driving wheels, the traction control device controls the braking mechanisms only for the driving wheels related to any two of axles while controlling the differential adjusting mechanism.

Abstract: Provided are a group III nitride composite substrate having a low sheet resistance and produced with a high yield, and a method for manufacturing the same, as well as a method for manufacturing a group III nitride semiconductor device using the group III nitride composite substrate. A group III nitride composite substrate includes a group III nitride film and a support substrate formed from a material different in chemical composition from the group III nitride film. The group III nitride film is joined to the support substrate in one of a direct manner and an indirect manner. The group III nitride film has a thickness of 10 ?m or more. A sheet resistance of a group III-nitride-film-side main surface is 200 ?/sq or less.

Abstract: Group-III nitride crystal composites made up of especially processed crystal slices, cut from III-nitride bulk crystal, whose major surfaces are of {1-10±2}, {11-2±2}, {20-2±1} or {22-4±1} orientation, disposed adjoining each other sideways with the major-surface side of each slice facing up, and III-nitride crystal epitaxially present on the major surfaces of the adjoining slices, with the III-nitride crystal containing, as principal impurities, either silicon atoms or oxygen atoms. With x-ray diffraction FWHMs being measured along an axis defined by a <0001> direction of the substrate projected onto either of the major surfaces, FWHM peak regions are present at intervals of 3 to 5 mm width. Also, with threading dislocation density being measured along a <0001> direction of the III-nitride crystal substrate, threading-dislocation-density peak regions are present at the 3 to 5 mm intervals.

Abstract: The present method of manufacturing a GaN-based film includes the steps of preparing a composite substrate (10) including a support substrate (11) dissoluble in hydrofluoric acid and a single crystal film (13) arranged on a side of a main surface (11m) of the support substrate (11), a coefficient of thermal expansion in the main surface (11m) of the support substrate (11) being more than 0.8 time and less than 1.2 times as high as a coefficient of thermal expansion of GaN crystal, forming a GaN-based film (20) on a main surface (13m) of the single crystal film (13) arranged on the side of the main surface (11m) of the support substrate (11), and removing the support substrate (11) by dissolving the support substrate (11) in hydrofluoric acid. Thus, the method of manufacturing a GaN-based film capable of efficiently obtaining a GaN-based film having a large main surface area, less warpage, and good crystallinity, as well as a composite substrate used therefor are provided.

Abstract: The present invention is to provide a method for growing a group III nitride crystal that has a large size and has a small number of pits formed in the main surface of the crystal by using a plurality of tile substrates. A method for growing a group III nitride crystal includes a step of preparing a plurality of tile substrates 10 including main surfaces 10m having a shape of a triangle or a convex quadrangle that allows two-dimensional close packing of the plurality of tile substrates; a step of arranging the plurality of tile substrates 10 so as to be two-dimensionally closely packed such that, at any point across which vertexes of the plurality of tile substrates 10 oppose one another, 3 or less of the vertexes oppose one another; and a step of growing a group III nitride crystal 20 on the main surfaces 10m of the plurality of tile substrates arranged.

Abstract: An object of the invention is to provide a traction control apparatus capable of suitably controlling an error, if it occurs, between an estimation of a vehicle speed and an actual vehicle speed. A traction control apparatus according to the invention includes a vehicle speed estimator and a driving-force controller. The traction control apparatus includes a vehicle state determiner that determines whether the vehicle speed of the construction vehicle estimated by the vehicle speed estimator and the driving-force control by the driving-force controller are balanced, and a driving-force control changer that changes a driving-force control by the driving-force controller when the vehicle state determiner determines the vehicle speed and the driving-force control to be unbalanced.

Abstract: The present method of manufacturing a GaN-based film includes the steps of preparing a composite substrate including a support substrate dissoluble in hydrofluoric acid and a single crystal film arranged on a side of a main surface of the support substrate, a coefficient of thermal expansion in the main surface of the support substrate being more than 0.8 time and less than 1.2 times as high as a coefficient of thermal expansion of GaN crystal, forming a GaN-based film on a main surface of the single crystal film arranged on the side of the main surface of the support substrate, and removing the support substrate by dissolving the support substrate in hydrofluoric acid. Thus, the method of manufacturing a GaN-based film capable of efficiently obtaining a GaN-based film having a large main surface area, less warpage, and good crystallinity, as well as a composite substrate used therefor are provided.