Abstract: A GaN epitaxial substrate contains a GaN substrate and a GaN buffer layer epitaxially grown on the GaN substrate. The GaN epitaxial substrate includes a point A and a point B which is positioned on a straight line parallel to a [0001] axis passing through the point A, the point B being present in a [0001] axis direction relative to the point A, the point A is present in the GaN substrate or the GaN buffer layer, the point B is present in the GaN buffer layer, a ratio ([Fe]B/[Fe]A) is 1/100, [Fe]A being a Fe concentration of the point A and [Fe]B being a Fe concentration of the point B, and a distance between the point A and the point B is 0.2 ?m or less.

Abstract: A GaN epitaxial substrate contains a GaN substrate and a GaN buffer layer epitaxially grown on the GaN substrate. The GaN epitaxial substrate includes a point A and a point B positioned on a straight line parallel to a [0001] axis passing through the point A, the point B being present in a [0001] axis direction relative to the point A. The point A is present in the GaN substrate or the GaN buffer layer, the point B is present in the GaN buffer layer, a ratio ([Mn]B/[Mn]A) is 1/100, and a distance between the point A and the point B is 0.7 ?m or less.

Abstract: A GaN substrate doped with manganese, in which an activation energy of a carrier is 0.7 eV or more when a carrier concentration is represented by the formula (I): carrier concentration (atoms/cm3)=A×EXP(?Ea/kT). In the formula (I), A represents a proportional constant, EXP represents an exponential function, Ea represents a carrier activation energy (eV), k represents a Boltzmann constant (8.617×10?5 eV/K), and T represents a temperature (K) in Kelvin units.

Abstract: Provided is an n-type GaN crystal, in which a donor impurity contained at the highest concentration is Ge, and which has a room-temperature resistivity of lower than 0.03 ?·cm and a (004) XRD rocking curve FWHM of less than 20 arcsec. The n-type GaN crystal has two main surfaces, each having an area of 3 cm2 or larger. One of the two main surfaces can have a Ga polarity and can be inclined at an angle of 0° to 10° with respect to a (0001) crystal plane. Further, the n-type GaN crystal can have a diameter of 20 mm or larger.

Abstract: Provided is an n-type GaN crystal, in which a donor impurity contained at the highest concentration is Ge, and which has a room-temperature resistivity of lower than 0.03 ?·cm and a (004) XRD rocking curve FWHM of less than 20 arcsec. The n-type GaN crystal has two main surfaces, each having an area of 2 cm2 or larger. One of the two main surfaces can have a Ga polarity and can be inclined at an angle of 0° to 10° with respect to a (0001) crystal plane. Further, the n-type GaN crystal can have a diameter of 20 mm or larger.

Abstract: A method for producing a GaN crystal that includes: (i) a seed crystal preparation step of preparing a GaN seed crystal having one or more facets selected from a {10-10} facet and a {10-1-1} facet; and (ii) a growth step of growing GaN from vapor phase on a surface comprising the one or more facets of the GaN seed crystal using GaCl3 and NH3 as raw materials.

Abstract: Provided is a GaN substrate wafer with an improved productivity, which can be preferably used in the production of a nitride semiconductor device having a horizontal device structure. The GaN substrate wafer is a (0001)-oriented GaN substrate wafer that includes a first region arranged on an N-polar side and a second region, which is arranged on a Ga-polar side and has a minimum thickness, via a regrowth interface therebetween. In this GaN substrate wafer, the second region has a minimum thickness of not less than 20 ?m, and at least a portion of the second region has a total compensating impurity concentration of 1×1017 atoms/cm3 or higher.

Abstract: Provided are: a GaN substrate wafer having a crystallinity suitable as a substrate for a semiconductor device as well as an improved productivity; and a method of producing the same. The GaN substrate wafer is a (0001)-oriented GaN substrate wafer that includes a first region arranged on an N-polar side and a second region arranged on a Ga-polar side via a regrowth interface therebetween. In this GaN substrate wafer, the second region has a minimum thickness of not less than 20 ?m, the concentration of at least one element selected from Li, Na, K, F, Cl, Br, and I in the first region is 1×1015 atoms/cm3 or higher, and the second region satisfies one or more conditions selected from the following (a) to (c): (a) the Si concentration is 5×1016 atoms/cm3 or higher; (b) the O concentration is 3×1016 atoms/cm3 or lower; and (c) the H concentration is 1×1017 atoms/cm3 or lower.

Abstract: The present invention is aimed at providing: a GaN substrate wafer having an improved productivity, which can be preferably used for the production of a nitride semiconductor device in which a device structure is arranged on a GaN substrate having a carrier concentration increased by doping; and a method of producing the same. Provided is a (0001)-oriented GaN wafer which includes a first region arranged on an N-polar side and a second region arranged on a Ga-polar side via a regrowth interface therebetween. In this GaN wafer, the second region has a minimum thickness of 20 ?m to 300 ?m, and contains a region having a higher donor impurity total concentration than the first region. In the second region, a region within a specific length from a main surface of the Ga-polar side of the GaN substrate wafer is defined as a main doped region, and the second region may be doped such that at least the main doped region has a donor impurity total concentration of 1×1018 atoms/cm3 or higher.

Abstract: A method for producing a GaN crystal that includes: (i) a seed crystal preparation step of preparing a GaN seed crystal having one or more facets selected from a {10-10} facet and a {10-1-1} facet; and (ii) a growth step of growing GaN from vapor phase on a surface comprising the one or more facets of the GaN seed crystal using GaCl3 and NH3 as raw materials.

Abstract: Provided is an n-type GaN crystal, in which a donor impurity contained at the highest concentration is Ge, and which has a room-temperature resistivity of lower than 0.03 ?·cm and a (004) XRD rocking curve FWHM of less than 20 arcsec. The n-type GaN crystal has two main surfaces, each having an area of 2 cm2 or larger. One of the two main surfaces can have a Ga polarity and can be inclined at an angle of 0° to 10° with respect to a (0001) crystal plane. Further, the n-type GaN crystal can have a diameter of 20 mm or larger.

Abstract: The present invention provides a novel method for producing a GaN crystal, the method including growing GaN from vapor phase on a semi-polar or non-polar GaN surface using GaCl3 and NH3 as raw materials. Provided herein is an invention of a method for producing a GaN crystal, including the steps of: (i) preparing a GaN seed crystal having a non-polar or semi-polar surface whose normal direction forms an angle of 85° or more and less than 170° with a [0001] direction of the GaN seed crystal; and (ii) growing GaN from vapor phase on a surface including the non-polar or semi-polar surface of the GaN seed crystal using GaCl3 and NH3 as raw materials.

Abstract: Provides is a C-plane GaN substrate which, although formed from a GaN crystal grown so that surface pits are generated, is free from any inversion domain, and moreover, has a low spiral dislocation density in a gallium polar surface. Provides is a C-plane GaN substrate wherein: the substrate comprises a plurality of facet growth areas each having a closed ring outline-shape on a gallium polar surface; the spiral dislocation density is less than 1×106 cm?2 anywhere on the gallium polar surface; and the substrate is free from any inversion domain. The C-plane GaN substrate may comprise a high dislocation density part having a dislocation density of more than 1×107 cm?2 and a low dislocation density part having a dislocation density of less than 1×106 cm?2 on the gallium polar surface.

Abstract: The present invention provides a novel method for producing a GaN crystal, the method including growing GaN from vapor phase on a semi-polar or non-polar GaN surface using GaCl3 and NH3 as raw materials. Provided herein is an invention of a method for producing a GaN crystal, including the steps of: (i) preparing a GaN seed crystal having a non-polar or semi-polar surface whose normal direction forms an angle of 85° or more and less than 170° with a [0001] direction of the GaN seed crystal; and (ii) growing GaN from vapor phase on a surface including the non-polar or semi-polar surface of the GaN seed crystal using GaCl3 and NH3 as raw materials.

Abstract: A C-plane GaN substrate only mildly restricts the shape and dimension of a nitride semiconductor device formed on the substrate. The variation of an off-angle on the main surface of the substrate is suppressed. In the C-plane GaN substrate: the substrate comprises a plurality of facet growth areas each having a closed ring outline-shape on the main surface; the number density of the facet growth area accompanied by a core among the plurality of facet growth areas is less than 5 cm?2 on the main surface; and, when any circular area of 4 cm diameter is selected from an area which is on the main surface and is distant by 5 mm or more from the outer peripheral edge of the substrate, the variation widths of an a-axis direction component and an m-axis direction component of an off-angle within the circular area is each 0.25 degrees or less.

Abstract: A C-plane GaN substrate only mildly restricts the shape and dimension of a nitride semiconductor device formed on the substrate. The variation of an off-angle on the main surface of the substrate is suppressed. In the C-plane GaN substrate: the substrate comprises a plurality of facet growth areas each having a closed ring outline-shape on the main surface; the number density of the facet growth area accompanied by a core among the plurality of facet growth areas is less than 5 cm?2 on the main surface; and, when any circular area of 4 cm diameter is selected from an area which is on the main surface and is distant by 5 mm or more from the outer peripheral edge of the substrate, the variation widths of an a-axis direction component and an m-axis direction component of an off-angle within the circular area is each 0.25 degrees or less.

Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an a-axis direction comprising a 0.15° or greater miscut angle towards the a-axis direction and a less than 30° miscut angle towards the a-axis direction.

Abstract: Provides is a C-plane GaN substrate which, although formed from a GaN crystal grown so that surface pits are generated, is free from any inversion domain, and moreover, has a low spiral dislocation density in a gallium polar surface. Provides is a C-plane GaN substrate wherein: the substrate comprises a plurality of facet growth areas each having a closed ring outline-shape on a gallium polar surface; the spiral dislocation density is less than 1×106 cm?2 anywhere on the gallium polar surface; and the substrate is free from any inversion domain. The C-plane GaN substrate may comprise a high dislocation density part having a dislocation density of more than 1×107 cm?2 and a low dislocation density part having a dislocation density of less than 1×106 cm?2 on the gallium polar surface.

Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate. The miscut angle towards the <000-1> direction is 0.75° or greater miscut and less than 27° miscut towards the <000-1> direction. Surface undulations are suppressed and may comprise faceted pyramids. A device fabricated using the film is also disclosed. A nonpolar III-nitride film having a smooth surface morphology fabricated using a method comprising selecting a miscut angle of a substrate upon which the nonpolar III-nitride films are grown in order to suppress surface undulations of the nonpolar III-nitride films. A nonpolar III-nitride-based device grown on a film having a smooth surface morphology grown on a miscut angle of a substrate which the nonpolar III-nitride films are grown. The miscut angle may also be selected to achieve long wavelength light emission from the nonpolar film.

Abstract: A nonpolar III-nitride film grown on a miscut angle of a substrate, in order to suppress the surface undulations, is provided. The surface morphology of the film is improved with a miscut angle towards an ?-axis direction comprising a 0.15° or greater miscut angle towards the ?-axis direction and a less than 30° miscut angle towards the ?-axis direction.