Abstract: There is provided a nitride semiconductor epitaxial substrate having a group III nitride semiconductor layer with C-plane as a surface, grown on a substrate via a buffer layer of the group III nitride semiconductor containing Al, wherein the buffer layer has an inversion domain on the surface.

Abstract: There is provided an apparatus for producing metal chloride gas, comprising: a source vessel configured to store a metal source; a gas supply port configured to supply chlorine-containing gas into the source vessel; a gas exhaust port configured to discharge metal chloride-containing gas containing metal chloride gas produced by a reaction between the chlorine-containing gas and the metal source, to outside of the source vessel; and a partition plate configured to form a gas passage continued to the gas exhaust port from the gas supply port by dividing a space in an upper part of the metal source in the source vessel, wherein the gas passage is formed in one route from the gas supply port to the gas exhaust port, with a horizontal passage width of the gas passage set to 5 cm or less, with bent portions provided on the gas passage.

Abstract: A nitride semiconductor template includes a substrate, and a group III nitride semiconductor layer formed on the substrate and including a Si-doped layer doped with Si as an uppermost layer thereof. The group III nitride semiconductor layer has a total thickness of not less than 4 ?m and not more than 10 ?m. The Si-doped layer includes a Si concentration gradient layer having a carrier concentration that gradually decreases toward an outermost surface thereof so as to be not less than 1×1017 cm?3 and not more than 5×1017 cm?3 at the outermost surface of the group III nitride semiconductor layer.

Abstract: A nitride semiconductor crystal producing method, a nitride semiconductor epitaxial wafer, and a nitride semiconductor freestanding substrate, by which it is possible to suppress the occurrence of cracking in the nitride semiconductor crystal and to ensure the enhancement of the yield of the nitride semiconductor crystal. The nitride semiconductor crystal producing method includes growing a nitride semiconductor crystal over a seed crystal substrate, while applying an etching action to an outer end of the seed crystal substrate during the growing of the nitride semiconductor crystal.

Abstract: A nitride semiconductor crystal producing method, includes growing a nitride semiconductor crystal over a seed crystal substrate, while applying an etching action to an outer end of the seed crystal substrate during the growing of the nitride semiconductor crystal.

Abstract: A nitride semiconductor template includes a substrate, and a group III nitride semiconductor layer having an oxygen-doped layer formed on the substrate, and a silicon-doped layer formed on the oxygen-doped layer. A total thickness of the group III nitride semiconductor layer is not smaller than 4 ?m and not greater than 10 ?m, and an average silicon carrier concentration in the silicon-doped layer is not lower than 1×1018 cm?3 and not higher than 5×1018 cm?3.

Abstract: There is provided a method for manufacturing a nitride semiconductor substrate, comprising: etching and flattening a surface of a nitride semiconductor substrate disposed facing a surface plate, by using the surface plate having a surface composed of any one of Ni, Ti, Cr, W, and Mo or nitride of any one of them, disposing the surface of the surface plate and a flattening surface of a nitride semiconductor substrate proximately so as to be faced each other, and supplying gas containing at least hydrogen and ammonia between the surface of the surface plate and the surface of the nitride semiconductor substrate, wherein the surface plate and the nitride semiconductor substrate facing each other are set in a high temperature state of 900° C. or more.

Abstract: A method of manufacturing a gallium nitride substrate includes machining a gallium nitride crystal, and wet-etching the gallium nitride crystal prior to the machining.

Abstract: A metal chloride gas generator includes a reactor including a receiving section for receiving a metal on an upstream side and a growing section in which a growth substrate is placed on a downstream side, a raw material section heater and a growing section heater each of which heats an inside of the reactor, an upstream end comprising a gas inlet, and a gas inlet pipe arranged to extend from the upstream end via the receiving section to the growing section, for introducing a chloride gas from the upstream end to supply the chloride gas to the receiving section and supplying a metal chloride gas produced by a reaction between the chloride gas and the metal in the receiving section to the growing section. The gas inlet pipe includes a suppressing section for suppressing an optical waveguiding phenomenon which waveguides a radiant heat from the growing section heater or the growing section.

Abstract: A nitride semiconductor growth substrate includes a principal surface including a C-plane of a sapphire substrate, and a convex portion that is formed on the principal surface, has a cone or pyramid shape or a truncated cone or pyramid shape, is disposed to form a lattice pattern in a top view thereof, and includes a side surface inclined at an angle of less than 90 degrees relative to the principal surface. The convex portion has a height of 0.5 to 3 ?m from the principal surface. A distance between adjacent ones of the convex portion is 1 to 6 ?m. The side surface of the convex portion has a surface roughness (RMS) of not more than 10 nm.

Abstract: To provide a method for manufacturing a nitride semiconductor substrate capable of reducing a cleavage during slicing of a nitride semiconductor single crystal, and capable of improving a yield rate of the nitride semiconductor substrate, comprising: growing a nitride semiconductor single crystal on a seed crystal substrate by vapor phase epitaxy; grinding an outer peripheral surface of the grown nitride semiconductor single crystal; and slicing the nitride semiconductor single crystal with its outer peripheral surface ground, wherein a grinding amount of the outer peripheral surface of the nitride semiconductor single crystal in the step of grinding is 1.5 mm or more.

Abstract: A nitride semiconductor crystal producing method, a nitride semiconductor epitaxial wafer, and a nitride semiconductor freestanding substrate, by which it is possible to suppress the occurrence of cracking in the nitride semiconductor crystal and to ensure the enhancement of the yield of the nitride semiconductor crystal. The nitride semiconductor crystal producing method includes growing a nitride semiconductor crystal over a seed crystal substrate, while applying an etching action to an outer end of the seed crystal substrate during the growing of the nitride semiconductor crystal.

Abstract: A nitride semiconductor template includes a substrate, and a group III nitride semiconductor layer having an oxygen-doped layer formed on the substrate, and a silicon-doped layer formed on the oxygen-doped layer. A total thickness of the group III nitride semiconductor layer is not smaller than 4 ?m and not greater than 10 ?m, and an average silicon carrier concentration in the silicon-doped layer is not lower than 1×1018 cm?3 and not higher than 5×1018 cm?3.

Abstract: A metal chloride gas generator includes: a tube reactor including a receiving section for receiving a metal on an upstream side, and a growing section in which a growth substrate is placed on a downstream side; a gas inlet pipe arranged to extend from an upstream end with a gas inlet via the receiving section to the growing section, for introducing a gas from the upstream end to supply the gas to the receiving section, and supplying a metal chloride gas produced by a reaction between the gas and the metal in the receiving section to the growing section; and a heat shield plate placed in the reactor to thermally shield the upstream end from the growing section. The gas inlet pipe is bent between the upstream end and the heat shield plate.

Abstract: There is provided a method for manufacturing a nitride semiconductor substrate, comprising: etching and flattening a surface of a nitride semiconductor substrate disposed facing a surface plate, by using the surface plate having a surface composed of any one of Ni, Ti, Cr, W, and Mo or nitride of any one of them, disposing the surface of the surface plate and a flattening surface of a nitride semiconductor substrate proximately so as to be faced each other, and supplying gas containing at least hydrogen and ammonia between the surface of the surface plate and the surface of the nitride semiconductor substrate, wherein the surface plate and the nitride semiconductor substrate facing each other are set in a high temperature state of 900° C. or more.

Abstract: There is provided a nitride semiconductor epitaxial substrate having a group III nitride semiconductor layer with C-plane as a surface, grown on a substrate via a buffer layer of the group III nitride semiconductor containing Al, wherein the buffer layer has an inversion domain on the surface.

Abstract: There is provided an apparatus for producing metal chloride gas, comprising: a source vessel configured to store a metal source; a gas supply port configured to supply chlorine-containing gas into the source vessel; a gas exhaust port configured to discharge metal chloride-containing gas containing metal chloride gas produced by a reaction between the chlorine-containing gas and the metal source, to outside of the source vessel; and a partition plate configured to form a gas passage continued to the gas exhaust port from the gas supply port by dividing a space in an upper part of the metal source in the source vessel, wherein the gas passage is formed in one route from the gas supply port to the gas exhaust port, with a horizontal passage width of the gas passage set to 5 cm or less, with bent portions provided on the gas passage.

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 nitride semiconductor crystal, comprising: laminated homogeneous nitride semiconductor layers, with a thickness of 2 mm or more, wherein the laminated homogeneous nitride semiconductor layers are constituted so that a nitride semiconductor layer with low dopant concentration and a nitride semiconductor layer with high dopant concentration are alternately laminated by two cycles or more.

Abstract: A zinc-blende nitride semiconductor free-standing substrate has a front surface and a back surface opposite the front surface. The distance between the front and back surfaces is not less than 200 ?m. The area ratio of the zinc-blende nitride semiconductor to the front surface is not less than 95%.