Abstract: There is provided a method of manufacturing a group III nitride semiconductor substrate including: a fixing step S10 of fixing abase substrate, which includes a group III nitride semiconductor layer having a semipolar plane as a main surface, to a susceptor; a first growth step S11 of forming a first growth layer by growing a group III nitride semiconductor over the main surface of the group III nitride semiconductor layer in a state in which the base substrate is fixed to the susceptor using an HVPE method; a cooling step S12 of cooling a laminate including the susceptor, the base substrate, and the first growth layer; and a second growth step S13 of forming a second growth layer by growing a group III nitride semiconductor over the first growth layer in a state in which the base substrate is fixed to the susceptor using the HVPE method.

Abstract: According to the present invention, there is provided a group III nitride semiconductor substrate (free-standing substrate 30) that is formed of group III nitride semiconductor crystals. Both exposed first and second main surfaces in a relationship of top and bottom are semipolar planes. A variation coefficient of an emission wavelength of each of the first and second main surfaces, which is calculated by dividing a standard deviation of an emission wavelength by an average value of the emission wavelength, is 0.05% or less in photoluminescence (PL) measurement in which mapping is performed in units of an area of 1 mm2 by emitting helium-cadmium (He—Cd) laser, which has a wavelength of 325 nm and an output of 10 mW or more and 40 mW or less, at room temperature. In a case where devices are manufactured over the free-standing substrate 30, variations in quality among the devices are suppressed.

Abstract: Provided is a method for manufacturing a group III nitride semiconductor substrate includes a substrate preparation step S10 of preparing a sapphire substrate, a heat treatment step S20 of performing a heat treatment on the sapphire substrate, a pre-flow step S30 of supplying a metal-containing gas over the sapphire substrate, a buffer layer forming step S40 of forming a buffer layer over the sapphire substrate under growth conditions of a growth temperature of 800° C. or higher and 950° C. or lower and a pressure of 30 torr or more and 200 torr or less, and a growth step S50 of forming a group III nitride semiconductor layer over the buffer layer under growth conditions of a growth temperature of 800° C. or higher and 1025° C. or lower, a pressure of 30 torr or more and 200 torr or less, and a growth speed of 10 ?m/h or more.

Abstract: There is provided a group III nitride semiconductor substrate (free-standing substrate (30)) that is formed of a group III nitride semiconductor crystal and has a thickness of 300 ?m or more and 1000 ?m or less. Both exposed first and second main surfaces in a relationship of top and bottom are semipolar planes. A difference in a half width of an X-ray rocking curve (XRC) measured by making X-rays incident on each of the first and second main surfaces in parallel to an m axis of the group III nitride semiconductor crystal is 500 arcsec or less.

Abstract: A method for manufacturing a group III nitride semiconductor substrate includes a preparation step S10 for preparing a group III nitride semiconductor substrate having a sapphire substrate having a semipolar plane as a main surface, and a group III nitride semiconductor layer positioned over the main surface, in which a <0002> direction of the sapphire substrate and a <10-10> direction of the group III nitride semiconductor layer do not intersect at right angles in a plan view in a direction perpendicular to the main surface, and a growth step S20 for epitaxially growing a group III nitride semiconductor over the group III nitride semiconductor layer.

Abstract: According to the present invention, there is provided a group III nitride semiconductor substrate (free-standing substrate 30) that is formed of group III nitride semiconductor crystals. Both exposed first and second main surfaces in a relationship of top and bottom are semipolar planes. A variation coefficient of an emission wavelength of each of the first and second main surfaces, which is calculated by dividing a standard deviation of an emission wavelength by an average value of the emission wavelength, is 0.05% or less in photoluminescence (PL) measurement in which mapping is performed in units of an area of 1 mm2 by emitting helium-cadmium (He—Cd) laser, which has a wavelength of 325 nm and an output of 10 mW or more and 40 mW or less, at room temperature. In a case where devices are manufactured over the free-standing substrate 30, variations in quality among the devices are suppressed.

Abstract: There is provided a group III nitride semiconductor substrate (free-standing substrate (30)) that is formed of a group III nitride semiconductor crystal and has a thickness of 300 ?m or more and 1000 ?m or less. Both exposed first and second main surfaces in a relationship of top and bottom are semipolar planes. A difference in a half width of an X-ray rocking curve (XRC) measured by making X-rays incident on each of the first and second main surfaces in parallel to an m axis of the group III nitride semiconductor crystal is 500 arcsec or less.

Abstract: There is provided a method of manufacturing a group III nitride semiconductor substrate including: a fixing step S10 of fixing a base substrate, which includes a group III nitride semiconductor layer having a semipolar plane as a main surface, to a susceptor; a first growth step S11 of forming a first growth layer by growing a group III nitride semiconductor over the main surface of the group III nitride semiconductor layer in a state in which the base substrate is fixed to the susceptor using an HVPE method; a cooling step S12 of cooling a laminate including the susceptor, the base substrate, and the first growth layer; and a second growth step S13 of forming a second growth layer by growing a group III nitride semiconductor over the first growth layer in a state in which the base substrate is fixed to the susceptor using the HVPE method.