An object is to provide a nonpolar or semipolar GaN substrate having improved size and crystal quality. A self-standing GaN substrate has an angle between the normal of the principal surface and an m-axis of 0 degrees or more and 20 degrees or less, wherein: the size of the projected image in a c-axis direction when the principal surface is vertically projected on an M-plane is 10 mm or more; and when an a-axis length is measured on an intersection line between the principal surface and an A-plane, a low distortion section with a section length of 6 mm or more and with an a-axis length variation within the section of 10.0×10.sup.−5 Å or less is observed.

A method for manufacturing a composite structure comprising a thin layer made of monocrystalline silicon carbide arranged on a carrier substrate made of silicon carbide, the method comprising: a) a step of providing a donor substrate made of monocrystalline SiC, the donor substrate comprising a donor layer produced by epitaxial growth on an initial substrate, the donor layer exhibiting a density of crystal defects that is lower than that of the initial substrate; b) a step of ion implantation of light species into the donor layer, in order to form a buried brittle plane delimiting the thin layer between the buried brittle plane and a free face of the donor layer; c) a succession of n steps of formation of carrier layers, with n greater than or equal to 2, the n carrier layers being arranged on the donor layer successively on one another and forming the carrier substrate, each step of formation comprising a chemical vapor deposition, at a temperature of between 400° C. and 1100° C., in order to form a carrier layer made of polycrystalline SiC, the n chemical vapor depositions being carried out at n different temperatures; d) a step of separation along the buried brittle plane, in order to form, on the one hand, a composite structure comprising the thin layer on the carrier substrate and, on the other hand, the remainder of the donor substrate; and e) a step of mechanical and/or chemical treatment(s) of the composite structure.

A method for manufacturing a composite structure comprising a thin layer made of monocrystalline silicon carbide arranged on a carrier substrate made of silicon carbide, the method comprising: a) a step of providing a donor substrate made of monocrystalline SiC, the donor substrate comprising a donor layer produced by epitaxial growth on an initial substrate, the donor layer exhibiting a density of crystal defects that is lower than that of the initial substrate; b) a step of ion implantation of light species into the donor layer, in order to form a buried brittle plane delimiting the thin layer between the buried brittle plane and a free face of the donor layer; c) a succession of n steps of formation of carrier layers, with n greater than or equal to 2, the n carrier layers being arranged on the donor layer successively on one another and forming the carrier substrate, each step of formation comprising a chemical vapor deposition, at a temperature of between 400° C. and 1100° C., in order to form a carrier layer made of polycrystalline SiC, the n chemical vapor depositions being carried out at n different temperatures; d) a step of separation along the buried brittle plane, in order to form, on the one hand, a composite structure comprising the thin layer on the carrier substrate and, on the other hand, the remainder of the donor substrate; and e) a step of mechanical and/or chemical treatment(s) of the composite structure.

A method for manufacturing a semiconductor film includes placing a semiconductor substrate including a β-Ga.sub.2O.sub.3-based single crystal in a reaction chamber of an HVPE apparatus. When the semiconductor substrate is placed so that the growth base surface faces upward, an inlet for a dopant-including gas into the space is positioned higher than an inlet for an oxygen-including gas into the space and an inlet for a Ga chloride gas into the space is positioned higher than the inlet for the dopant-including gas into the space. When the semiconductor substrate is placed so that the growth base surface faces downward, the inlet for the dopant-including gas into the space is positioned higher than the inlet for the Ga chloride gas into the space and the inlet for the oxygen-including gas into the space is positioned higher than the inlet for the dopant-including gas into the space.

A method for manufacturing a semiconductor film includes placing a semiconductor substrate including a β-Ga.sub.2O.sub.3-based single crystal in a reaction chamber of an HVPE apparatus. When the semiconductor substrate is placed so that the growth base surface faces upward, an inlet for a dopant-including gas into the space is positioned higher than an inlet for an oxygen-including gas into the space and an inlet for a Ga chloride gas into the space is positioned higher than the inlet for the dopant-including gas into the space. When the semiconductor substrate is placed so that the growth base surface faces downward, the inlet for the dopant-including gas into the space is positioned higher than the inlet for the Ga chloride gas into the space and the inlet for the oxygen-including gas into the space is positioned higher than the inlet for the dopant-including gas into the space.

A method for manufacturing a semiconductor device includes: preparing a processed wafer having a gallium nitride (GaN) wafer and an epitaxial layer on the GaN wafer; forming a device constituent part in a portion of the processes wafer adjacent to a front surface provided by the epitaxial layer; forming a modified layer inside of the processed wafer by applying a laser beam from a back surface side opposite to the front surface side: and dividing the processed wafer at the modified layer. The processed wafer prepared includes a reflective layer for reflecting the laser beam at a position separated from a planned formation position, where the modified layer is to be formed, by a predetermined distance toward the front surface side. The reflective layer contains a layer having a refractive index different from that of a GaN single crystal of an epitaxial layer.

A method for manufacturing a semiconductor device includes: preparing a processed wafer having a gallium nitride (GaN) wafer and an epitaxial layer on the GaN wafer; forming a device constituent part in a portion of the processes wafer adjacent to a front surface provided by the epitaxial layer; forming a modified layer inside of the processed wafer by applying a laser beam from a back surface side opposite to the front surface side: and dividing the processed wafer at the modified layer. The processed wafer prepared includes a reflective layer for reflecting the laser beam at a position separated from a planned formation position, where the modified layer is to be formed, by a predetermined distance toward the front surface side. The reflective layer contains a layer having a refractive index different from that of a GaN single crystal of an epitaxial layer.

A semiconductor device and a method of manufacturing a semiconductor device according to one or more embodiments are disclosed. An interface layer is formed by implanting ionized impurities into a first layer comprising single-crystalline silicon carbide (SiC). Surfaces of the interface layer and a second layer comprising polycrystalline silicon carbide (SiC) are activated. The activated surfaces of the interface layer and the second layer are contacted and bonded. A covering layer is formed to cover a top surface and sides of the first layer, sides of the interface layer, and sides of the second layer.

A semiconductor device and a method of manufacturing a semiconductor device according to one or more embodiments are disclosed. An interface layer is formed by implanting ionized impurities into a first layer comprising single-crystalline silicon carbide (SiC). Surfaces of the interface layer and a second layer comprising polycrystalline silicon carbide (SiC) are activated. The activated surfaces of the interface layer and the second layer are contacted and bonded. A covering layer is formed to cover a top surface and sides of the first layer, sides of the interface layer, and sides of the second layer.

A semiconductor device has a first substrate made of a first semiconductor material, such as silicon. A sacrificial layer is formed over a first surface of the first substrate. A seed layer is formed over the sacrificial layer. A compliant layer is formed over a second surface of the first substrate opposite the first surface of the first substrate. A first semiconductor layer made of a second semiconductor material, such as silicon carbide, dissimilar from the first semiconductor material is formed over the sacrificial layer. The first substrate and sacrificial layer are removed leaving the first semiconductor layer substantially defect-free. The first semiconductor layer containing the second semiconductor material is formed at a temperature greater than a melting point of the first semiconductor material. A second semiconductor layer is formed over the first semiconductor layer with an electrical component formed in the second semiconductor layer.