Abstract: A production apparatus for producing a structural body includes: a holding mechanism that holds a processing target in contact with an etching solution, the processing target including an etch region that is made of a Group III nitride, and on which photoelectrochemical etching is to be performed; a light emitting device that irradiates the processing target with first light for performing the photoelectrochemical etching; a light emitting device that irradiates the processing target with second light that has a wavelength longer than that of the first light; and a measurement device that measures reflected light resulting from the second light being reflected off a surface of the etch region.

Abstract: There is provided a semiconductor device, including: a substrate; a group III nitride layer on the substrate, the group III nitride layer containing group III nitride; and a recess on the group III nitride layer, the group III nitride layer including: a channel layer, and a barrier layer on the channel layer, thereby forming a two-dimensional electron gas in the channel layer, the barrier layer including: a first layer containing aluminum gallium nitride, and a second layer on the first layer, the second layer containing aluminum gallium nitride added with an n-type impurity, wherein the recess is formed by removing all or a part of a thickness of the second layer, and at least a part of a thickness of the first layer is arranged below the recess.

Abstract: There is provided a method for manufacturing a semiconductor structure, including: preparing a plate-like semiconductor structure; and inspecting the semiconductor structure, the inspection of the semiconductor further including: performing a measurement of irradiating a surface of the semiconductor structure with a light from a light source in an oblique direction to the surface, and detecting a reflected light reflected or scattered by the surface by a two-dimensional detector, at a plurality of locations within at least a predetermined range of the surface of the semiconductor structure, to acquire a reflected light distribution that is a distribution of an integrated value obtained by integrating intensity of the reflected light measured at the plurality of locations, with respect to a position at the detector; and fitting the reflected light distribution by a multiple Gaussian function obtained by adding at least a first Gaussian function and a second Gaussian function distributed more widely than the fi

Abstract: A method for manufacturing a structure, including photoelectrochemically etching an etching object, the photoelectrochemical etching of the etching object including: injecting an alkaline or acidic etching solution containing an oxidizing agent that receives electrons, into a rotatably held container in which an etching object at least whose surface is composed of group III nitride is held, and immersing the surface in the etching solution; irradiating the surface of the etching object held in the container with light in a stationary state of the etching object and the etching solution; and rotating the container to scatter the etching solution toward an outer peripheral side, thereby discharging the etching solution from the container, after the surface is irradiated with the light.

Abstract: There is provided a method for manufacturing a structure, including: forming a recess portion by performing a first etching to a surface of a member composed of Group III nitride; and flattening a bottom of the recess portion by performing a second etching to the bottom, wherein in forming the recess portion, a flat portion and a protruding portion are formed on the bottom of the recess portion, the protruding portion being raised with respect to the flat portion because it is less likely to be etched by the first etching than the flat portion, and in flattening the bottom, by etching the protruding portion by the second etching, the protruding portion is lowered.

Abstract: There is provided a method for manufacturing a structure, including: applying a first etching to a surface of a member, at least the surface being composed of Group III nitride; and applying a second etching to the surface to which the first etching has been applied, wherein in applying the first etching, a flat portion and a protruding portion are formed, the flat portion being newly appeared on the surface by etching, and the protruding portion being raised with respect to the flat portion, which is caused by being less likely to be etched than the flat portion, and in applying the second etching, the protruding portion is lowered by etching the protruding portion.

Abstract: An object is to improve quality of a nitride crystal. A crystal represented by a composition formula InxAlyGa1?x?yN (satisfying 0?x?1, 0?y?1, and 0?x+y?1), wherein the concentration of carbon in the crystal is less than 1×1015 cm?3, and the concentration of an electron trap E3 that exits in an energy range from 0.5 eV to 0.65 eV from a lower end of a conduction band in the crystal is less than 1×1014 cm?3.

Abstract: There is provided a structure manufacturing method, including: preparing a wafer at least whose surface comprises Group III nitride crystal in a state of being immersed in an etching solution containing peroxodisulfate ions; and irradiating the surface of the wafer with light through the etching solution; wherein the group III nitride crystal has a composition in which a wavelength corresponding to a band gap is 310 nm or more, and during irradiation of the light, the surface of the wafer is irradiated with a first light having a wavelength of 200 nm or more and less than 310 nm under a first irradiation condition, and is irradiated with a second light having a wavelength of 310 nm or more and less than a wavelength corresponding to the band gap under a second irradiation condition controlled independently of the first irradiation condition.

Abstract: A structure manufacturing method including: preparing a treatment object that includes an etching target having a surface to be etched comprising a conductive group III nitride and a region to be etched, a conductive member in contact with at least a portion of a surface of a conductive region of the etching target that is electrically connected to the region to be etched, and a mask formed on the surface to be etched and comprising a non-conductive material; and etching the group III nitride by immersing the treatment object in an alkaline or acidic etching solution containing peroxodisulfate ions as an oxidizing agent that accepts electrons, and irradiating the surface to be etched with light through the etching solution, wherein an edge that defines the region to be etched is constituted by an edge of the mask without including an edge of the conductive member.

Abstract: There is provided a nitride crystal substrate constituted by group-III nitride crystal, containing n-type impurities, with an absorption coefficient ? being approximately expressed by equation (1) by a least squares method in a wavelength range of at least 1 ?m or more and 3.3 ?m or less. ?=NeK?a??(1) (where 1.5×10?19?K?6.0×10?19, a=3), here, a wavelength is ? (?m), an absorption coefficient of the nitride crystal substrate at 27° C. is ? (cm?1), a carrier concentration in the nitride crystal substrate is Ne (cm?3), and K and a are constants, wherein an error of an actually measured absorption coefficient with respect to the absorption coefficient ? obtained from equation (1) at a wavelength of 2 ?m is within ±0.1?, and in a reflection spectrum measured by irradiating the nitride crystal substrate with infrared light, there is no peak with a peak top within a wavenumber range of 1,200 cm?1 or more and 1,500 cm?1 or less.

Abstract: This invention provides a novel structure formed from GaN material using PEC etching. The structure comprises a member constituted by a single crystal of gallium nitride and the member includes a recess having an aspect ratio of 5 or more.

Abstract: A process of preparing a wafer having a diameter of two inches or more, at least a surface of the wafer being formed from a group III nitride crystal, including preparing an alkaline or acidic etching liquid containing a peroxodisulfate ion as an oxidizing agent that accepts an electron, accommodating the wafer such that the surface of the wafer is immersed in the etching liquid such that the surface of the wafer is parallel with a surface of the etching liquid; and radiating light from the surface side of the etching liquid onto the surface of the wafer without agitating the etching liquid. First and second etching areas disposed at an interval from each other are defined on the surface of the wafer. In the process of radiating the light onto the surface of the wafer, the light is radiated perpendicularly onto surfaces of the first and second etching areas.

Abstract: There is provided a structure manufacturing method, including: preparing an etching target with at least one surface comprising group III nitride; then in a state where the etching target is immersed in an etching solution containing peroxodisulfate ions; irradiating the surface of the etching target with light through the etching solution, and generating sulfate ion radicals from the peroxodisulfate ions and generating holes in the group III nitride, thereby etching the group III nitride, wherein in the etching of the group III nitride, the etching solution remains acidic during a period for etching the group III nitride by making the etching solution acidic at a start of etching the group III nitride, and the etching is performed, with a resist mask formed on the surface.

Abstract: There is provided a structure manufacturing method, including: preparing a wafer at least whose surface comprises Group III nitride crystal in a state of being immersed in an etching solution containing peroxodisulfate ions; and irradiating the surface of the wafer with light through the etching solution; wherein the group III nitride crystal has a composition in which a wavelength corresponding to a band gap is 310 nm or more, and during irradiation of the light, the surface of the wafer is irradiated with a first light having a wavelength of 200 nm or more and less than 310 nm under a first irradiation condition, and is irradiated with a second light having a wavelength of 310 nm or more and less than a wavelength corresponding to the band gap under a second irradiation condition controlled independently of the first irradiation condition.

Abstract: An object of the present invention is to improve quality of a nitride crystal, and also improve performance and manufacturing yield of a semiconductor device manufactured using the crystal. Provided is a nitride crystal in which a composition formula is represented by InxAlyGa1-x-yN (satisfying 0?x?1, 0?y?1, 0?x+y?1), and the concentration of B in the crystal is less than 1×1015 at/cm3, and each of the concentrations of O and C in the crystal is less than 1×1015 at/cm3 in a region of 60% or more of a main surface.

Abstract: There is provided a nitride crystal substrate comprising group-III nitride crystal and containing n-type impurities, wherein an absorption coefficient ? is approximately expressed by equation (1) in a wavelength range of at least 1 ?m or more and 3.3 ?m or less: ?=n K?a (1) (wherein, ?(?m) is a wavelength, ?(cm?1) is absorption coefficient of the nitride crystal substrate at 27° C., n (cm?3) is a free electron concentration in the nitride crystal substrate, and K and a are constants, satisfying 1.5×10?19?K?6.0×10?19, a=3).

Abstract: A nitride semiconductor substrate that is constituted by a single crystal of a group III nitride semiconductor and includes a main surface for which the closest low index crystal plane is a (0001) plane includes an inclined interface growth region that has grown with inclined interfaces other than the (0001) plane serving as growth surfaces. A ratio of an area occupied by the inclined interface growth region in the main surface is 80% or more. When a dislocation density is determined based on a dark spot density by observing the main surface in a field of view that is 250 ?m square using a multiphoton excitation microscope, the main surface does not include a region that has a dislocation density higher than 3×106 cm?2, and the main surface includes dislocation-free regions that are 50 ?m square and do not overlap each other, at a density of 100 regions/cm2 or more.

Abstract: A process of preparing a wafer having a diameter of two inches or more, at least a surface of the wafer being formed from a group III nitride crystal, including preparing an alkaline or acidic etching liquid containing a peroxodisulfate ion as an oxidizing agent that accepts an electron, accommodating the wafer such that the surface of the wafer is immersed in the etching liquid such that the surface of the wafer is parallel with a surface of the etching liquid; and radiating light from the surface side of the etching liquid onto the surface of the wafer without agitating the etching liquid. First and second etching areas disposed at an interval from each other are defined on the surface of the wafer. In the process of radiating the light onto the surface of the wafer, the light is radiated perpendicularly onto surfaces of the first and second etching areas.

Abstract: A method for manufacturing a nitride semiconductor substrate by using a vapor phase growth method includes: a step of preparing a base substrate that is constituted by a material different from a single crystal of a group III nitride semiconductor; a step of growing a base layer on the upper side of the base substrate; a first step of growing a first layer by epitaxially growing a single crystal of a group III nitride semiconductor directly on the base surface of the base layer, the single crystal of the group III nitride semiconductor having a top surface at which a (0001) plane is exposed, and a plurality of recessed portions formed by inclined interfaces other than the (0001) plane being generated in the top surface; and a second step of growing a second layer that has a mirror-finished surface.

Abstract: There is provided an epitaxial substrate, including: a GaN substrate whose main surface is a c-plane; and a GaN layer epitaxially grown on the main surface, wherein the main surface includes a region where an off-angle is 0.4° or more, and an E3 trap concentration in the GaN layer grown on the region is 3.0×1013 cm?3 or less.