Abstract: A nitride semiconductor free-standing substrate includes a nitride semiconductor crystal and an inversion domain with a density of not less than 10/cm2 and not more than 600/cm2 in a section parallel to a surface of the substrate and inside the substrate. A method for making the nitride semiconductor free-standing substrate includes a nitride semiconductor crystal growth step of growing on a heterosubstrate a nitride semiconductor crystal including an inversion domain with a density of not less than 10/cm2 and not more than 600/cm2 by adjusting a growth condition at an initial growth stage of the nitride semiconductor crystal, and a separation step for separating the grown nitride semiconductor crystal from the heterosubstrate to form the nitride semiconductor free-standing substrate.

Abstract: A group III nitride semiconductor free-standing substrate includes an as-grown surface, more than half of a region of the as-grown surface including a single crystal plane. The single crystal plane includes an off-angle inclined in an m-axis or a-axis direction from a C-plane with a group III polarity, or in a c-axis or a-axis direction from an M-plane.

Abstract: To provide a group-III nitride semiconductor freestanding substrate, with carrier concentration of a peripheral part of a n-type group-III nitride semiconductor freestanding substrate set to be lower than the carrier concentration inside of the peripheral part. In this freestanding substrate, preferably value ?? obtained by dividing a difference between a maximum value of the carrier concentration and a minimum value of the carrier concentration in a surface of the freestanding substrate by the maximum value of the carrier concentration is greater than 0.05, and the carrier concentration in any place in the surface of the freestanding substrate exceeds 5.0×1017 cm?3.

Abstract: A group III nitride semiconductor free-standing substrate includes an as-grown surface, more than half of a region of the as-grown surface including a single crystal plane. The single crystal plane includes an off-angle inclined in an m-axis or a-axis direction from a C-plane with a group III polarity, or in a c-axis or a-axis direction from an M-plane.

Abstract: A structure of a substrate used for growing a crystal layer of a semiconductor, particularly a group-III nitride semiconductor and its manufacturing method. The substrate comprises two porous layers on a base. The mean opening diameter of the pores of the first porous laser, the outermost layer, is smaller than the means diameter of the pores in the second porous layer nearer to the base than the first porous layer. The first and second porous layers have volume porosities of 10 to 90%. More then 50% of the pores of the first porous layer extend from the surface of the first porous layer and reach the interface between the first and second porous layers. Even by a conventional crystal growing method, an epitaxial crystal of low defect density can be easily grown on the porous substrate.

Abstract: To provide a group-III nitride semiconductor freestanding substrate, with carrier concentration of a peripheral part of a n-type group-III nitride semiconductor freestanding substrate set to be lower than the carrier concentration inside of the peripheral part. In this freestanding substrate, preferably value ?? obtained by dividing a difference between a maximum value of the carrier concentration and a minimum value of the carrier concentration in a surface of the freestanding substrate by the maximum value of the carrier concentration is greater than 0.05, and the carrier concentration in any place in the surface of the freestanding substrate exceeds 5.0×1017cm?3.

Abstract: A nitride semiconductor free-standing substrate includes a nitride semiconductor crystal and an inversion domain with a density of not less than 10/cm2 and not more than 600/cm2 in a section parallel to a surface of the substrate and inside the substrate. A method for making the nitride semiconductor free-standing substrate includes a nitride semiconductor crystal growth step of growing on a heterosubstrate a nitride semiconductor crystal including an inversion domain with a density of not less than 10/cm2 and not more than 600/cm2 by adjusting a growth condition at an initial growth stage of the nitride semiconductor crystal, and a separation step for separating the grown nitride semiconductor crystal from the heterosubstrate to form the nitride semiconductor free-standing substrate.

Abstract: A structure of a substrate used for growing a crystal layer of a semiconductor, particularly a group-III nitride semiconductor and its manufacturing method. The substrate comprises two porous layers on a base. The mean opening diameter of the pores of the first porous laser, the outermost layer, is smaller than the means diameter of the pores in the second porous layer nearer to the base than the first porous layer. The first and second porous layers have volume porosities of 10 to 90%. More then 50% of the pores of the first porous layer extend from the surface of the first porous layer and reach the interface between the first and second porous layers. Even by a conventional crystal growing method, an epitaxial crystal of low defect density can be easily grown on the porous substrate.