Abstract: A method of producing a light-emitting semiconductor device of a group III nitride compound includes forming a high carrier concentration N+-layer satisfying the formula (Alx3Ga1-x3)y3In1-y3N, wherein 0?x3?1, 0?y3?1 and 0?x3+y3?1, forming an emission layer of a group III nitride compound semiconductor satisfying the formula, Alx1Gay1In1-x1-y1N, where 0?x1?1, 0?y1?1 and 0?x1+y1?1 on the high carrier concentration layer N+-layer, and forming a P-layer of a P-type conduction, on the emission layer, the P-layer including aluminum gallium nitride satisfying the formula Alx2Ga1-x2N, wherein 0?x2?1.

Abstract: A GaN single crystal 20 is grown on a crystal growth surface of a seed crystal (GaN layer 13) through the flux method in a nitrogen (N2) atmosphere at 3.7 MPa and 870° C. employing a flux mixture including Ga, Na, and Li at about 870° C. Since the back surface of the template 10 is R-plane of the sapphire substrate 11, the template 10 is readily corroded or dissolved in the flux mixture from the back surface thereof. Therefore, the template 10 is gradually dissolved or corroded from the back surface thereof, resulting in separation from the semiconductor or dissolution in the flux. When the GaN single crystal 20 is grown to a sufficient thickness, for example, about 500 ?m or more, the temperature of the crucible is maintained at 850° C. to 880° C., whereby the entirety of the sapphire substrate 11 is dissolved in the flux mixture.

Abstract: Objects of the invention are to further enhance crystallinity and crystallinity uniformity of a semiconductor crystal produced through the flux method, and to effectively enhance the production yield of the semiconductor crystal. The c-axis of a seed crystal including a GaN single-crystal layer is aligned in a horizontal direction (y-axis direction), one a-axis of the seed crystal is aligned in the vertical direction, and one m-axis is aligned in the x-axis direction. Thus, three contact points at which a supporting tool contacts the seed crystal are present on m-plane. The supporting tool has two supporting members, which extend in the vertical direction. One supporting member has an end part, which is inclined at 30° with respect to the horizontal plane ?. The reasons for supporting a seed crystal at m-plane thereof are that m-plane exhibits a crystal growth rate, which is lower than that of a-plane, and that desired crystal growth on c-plane is not inhibited.

Abstract: In the flux method, a source nitrogen gas is sufficiently heated before feeding to an Na—Ga mixture. The apparatus of the invention is provided for producing a group III nitride based compound semiconductor. The apparatus includes a reactor which maintains a group III metal and a metal differing from the group III metal in a molten state, a heating apparatus for heating the reactor, an outer vessel for accommodating the reactor and the heating apparatus, and a feed pipe for feeding a gas containing at least nitrogen from the outside of the outer vessel into the reactor. The feed pipe has a zone for being heated together with the reactor by means of the heating apparatus, wherein the zone is heated inside the outer vessel and outside the reactor.

Abstract: The present invention provides a method for producing a semiconductor substrate, the method including reacting nitrogen (N) with gallium (Ga), aluminum (Al), or indium (In), which are group III elements, in a flux mixture containing a plurality of metal elements selected from among alkali metals and alkaline earth metals, to thereby grow a group III nitride based compound semiconductor crystal. The group III nitride based compound semiconductor crystal is grown while the flux mixture and the group III element are mixed under stirring. At least a portion of a base substrate on which the group III nitride based compound semiconductor crystal is grown is formed of a flux-soluble material, and the flux-soluble material is dissolved in the flux mixture, at a temperature near the growth temperature of the group III nitride based compound semiconductor crystal, during the course of growth of the semiconductor crystal.

Abstract: In the Na flux method, a target semiconductor layer is separated from a sapphire substrate of a template substrate. The template substrate formed of the sapphire substrate and a GaN layer is placed in a Ga—Na molten mixture. The temperature the molten mixture and the nitrogen pressure are adjusted to 850° C. and 2.5 MPa, respectively. Under the conditions, a part of the GaN layer is melted back until the surface of the sapphire substrate is exposed, so that the remaining portion of the GaN layer is left in the form of a plurality of upright columns. Then, the pressure is elevated to 3 MPa, whereby a target GaN layer is grown on the processed GaN layer. Through lowering temperature, stress due to the difference in linear expansion coefficient and lattice constant between sapphire and GaN is generated, to thereby generate cracks in the processed GaN layer. By virtue of the cracking, the target GaN layer is separated from the sapphire substrate.

Abstract: A method of producing a light-emitting semiconductor device of a group III nitride compound includes forming an N-layer of an N-type conduction, the N-layer comprising gallium nitride, forming a high carrier concentration N+-layer satisfying the formula (Alx3Ga1-x3)y3In1-y3N, wherein 0?x3?1, 0?y3?1 and 0?x3+y3?1, on the N-layer, forming an emission layer of a group III nitride compound semiconductor satisfying the formula, Alx1Gay1In1-x1-y1N, where 0?x1?1, 0?y1?1 and 0?x1+y1?1 on the high carrier concentration layer N+layer, doping Si and Zn into the emission layer, forming a P-layer of a P-type conduction, on the emission layer, the P-layer including aluminum gallium nitride satisfying the formula Alx2Ga1-x2N, wherein 0?x2?1, and forming a contact layer of a P-type conduction, on the P-type layer, the contact layer including gallium nitride.

Abstract: A light-emitting semiconductor device (10) consecutively includes a sapphire substrate (1), an AlN buffer layer (2), a silicon (Si) doped GaN n+-layer (3) of high carrier (n-type) concentration, a Si-doped (Alx3Ga1?x3)y3In1?y3N n+-layer (4) of high carrier (n-type) concentration, a zinc (Zn) and Si-doped (Alx2Ga1?x2)y2In1?y2N emission layer (5), and a Mg-doped (Alx1Ga1?x1)y1In1?y1N p-layer (6). The AlN layer (2) has a 500 ? thickness. The GaN n+-layer (3) has about a 2.0 ?m thickness and a 2×1018/cm3 electron concentration. The n+-layer (4) has about a 2.0 ?m thickness and a 2×1018/cm3 electron concentration. The emission layer (5) has about a 0.5 ?m thickness. The p-layer 6 has about a 1.0 ?m thickness and a 2×1017/cm3 hole concentration. Nickel electrodes (7, 8) are connected to the p-layer (6) and n+-layer (4), respectively. A groove (9) electrically insulates the electrodes (7, 8).

Abstract: The present invention provides a method for producing a semiconductor substrate, the method including reacting nitrogen (N) with gallium (Ga), aluminum (Al), or indium (In), which are group III elements, in a flux mixture containing a plurality of metal elements selected from among alkali metals and alkaline earth metals, to thereby grow a group III nitride based compound semiconductor crystal. The group III nitride based compound semiconductor crystal is grown while the flux mixture and the group III element are mixed under stirring. At least a portion of a base substrate on which the group III nitride based compound semiconductor crystal is grown is formed of a flux-soluble material, and the flux-soluble material is dissolved in the flux mixture, at a temperature near the growth temperature of the group III nitride based compound semiconductor crystal, during the course of growth of the semiconductor crystal.

Abstract: An object of the invention is to carry out the flux method with improved work efficiency while maintaining the purity of flux at high level and saving flux material cost. The sodium-purifying apparatus includes a sodium-holding-and-management apparatus for maintaining purified sodium (Na) in a liquid state. Liquid sodium is supplied into a sodium-holding-and-management apparatus through a liquid-sodium supply piping maintained at 100° C. to 200° C. The sodium-holding-and-management apparatus further has an argon-gas-purifying apparatus for controlling the condition of argon (Ar) gas that fills the internal space thereof. Thus, by opening and closing a faucet at desired timing, purified liquid sodium (Na) supplied from the sodium-purifying apparatus can be introduced into a crucible as appropriate via the liquid-sodium supply piping, the sodium-holding-and-management apparatus, and the piping.

Abstract: A GaN single crystal 20 is grown on a crystal growth surface of a seed crystal (GaN layer 13) through the flux method in a nitrogen (N2) atmosphere at 3.7 MPa and 870° C. employing a flux mixture including Ga, Na, and Li at about 870° C. Since the back surface of the template 10 is R-plane of the sapphire substrate 11, the template 10 is readily corroded or dissolved in the flux mixture from the back surface thereof. Therefore, the template 10 is gradually dissolved or corroded from the back surface thereof, resulting in separation from the semiconductor or dissolution in the flux. When the GaN single crystal 20 is grown to a sufficient thickness, for example, about 500 ?m or more, the temperature of the crucible is maintained at 850° C. to 880° C., whereby the entirety of the sapphire substrate 11 is dissolved in the flux mixture.

Abstract: An object of the present invention is to realize, by the flux process, the production of a high-quality n-type semiconductor crystal having high concentration of electrons. The method of the invention for producing an n-type Group III nitride-based compound semiconductor by the flux process, the method including preparing a melt by melting at least a Group III element by use of a flux; supplying a nitrogen-containing gas to the melt; and growing an n-type Group III nitride-based compound semiconductor crystal on a seed crystal from the melt. In the method, carbon and germanium are dissolved in the melt, and germanium is incorporated as a donor into the semiconductor crystal, to thereby produce an n-type semiconductor crystal. The mole percentage of germanium to gallium in the melt is 0.05 mol % to 0.5 mol %, and the mole percentage of carbon to sodium is 0.1 mol % to 3.0 mol %.

Abstract: Provided is a method for producing a Group III nitride-based compound semiconductor having an M-plane main surface. The method employs a sapphire substrate having a main surface which is inclined by 30° with respect to R-plane about a line of intersection Lsapph-AM formed by R-plane and A-plane perpendicular thereto. R-plane surfaces of the sapphire substrate are exposed, and a silicon dioxide mask is formed on the main surface of the substrate. AlN buffer layers are formed on the exposed R-plane surfaces. A GaN layer is formed on the AlN buffer layers. At an initial stage of GaN growth, the top surface of the sapphire substrate is entirely covered with the GaN layer through lateral growth.

Abstract: In the flux method, a source nitrogen gas is sufficiently heated before feeding to an Na—Ga mixture. The apparatus of the invention is provided for producing a group III nitride based compound semiconductor The apparatus includes a reactor which maintains a group III metal and a metal differing from the group III metal in a molten state, a heating apparatus for heating the reactor, an outer vessel for accommodating the reactor and the heating apparatus, and a feed pipe for feeding a gas containing at least nitrogen from the outside of the outer vessel into the reactor. The feed pipe has a zone for being heated together with the reactor by means of the heating apparatus, wherein the zone is heated inside the outer vessel and outside the reactor.

Abstract: An object of the invention is to prevent, in the flux method, diffusion of substances that constitute the atmosphere of the outer vessel into the reactor. The apparatus for producing a group III nitride based compound semiconductor, the apparatus including a reactor which maintains a group III metal and a metal differing from the group III metal in a molten state, a heating apparatus for heating the reactor, and an outer vessel for accommodating the reactor and the heating apparatus, characterized in that diffusion of substances that constitute the atmosphere of the outer vessel into the reactor is prevented.

Abstract: To provide a semiconductor substrate of high quality suitable for fabricating an electronic device or an optical device. The present invention provides a method for producing a semiconductor substrate for an electronic device or an optical device, the method including reacting nitrogen (N) with gallium (Ga), aluminum (Al), or indium (In), which are group III elements, in a flux mixture containing a plurality of metal elements selected from among alkali metals and alkaline earth metals, to thereby grow a group III nitride based compound semiconductor crystal. The group III nitride based compound semiconductor crystal is grown while the flux mixture and the group III element are mixed under stirring.

Abstract: The present invention provides an apparatus for producing a Group III nitride semiconductor, which enables production of a uniform Si-doped GaN crystal. In one embodiment of the invention, an apparatus for producing a Group III nitride semiconductor includes a supply tube for supplying nitrogen and silane, a Ga-supplying apparatus for supplying Ga melt to a crucible, and an Na-supplying apparatus for supplying Na melt to the crucible. Nitrogen and a dopant is mixed together, and the gas mixture is supplied through one single supply tube without provision of a conventionally employed supply tube for only supplying a dopant. Thus, dead space in a reaction vessel is reduced, and vaporization of Na is suppressed, whereby a high-quality, Si-doped GaN crystal can be produced.

Abstract: The invention provides a group III nitride semiconductor manufacturing system which is free from interruption to rotation of a rotational shaft.

Abstract: An apparatus for manufacturing a Group III nitride semiconductor is composed of a pressure vessel, a reaction vessel disposed within the pressure vessel, a heating device disposed within the pressure vessel so as to heat the reaction vessel, and a glove box filled with argon gas. The pressure vessel and the glove box are connected to each other via a gate valve. By virtue of this configuration, a large-sized reusable reaction vessel can be disposed within the pressure vessel without causing oxidation of Na.

Abstract: A Group III nitride semiconductor crystal is grown according to a flux method. After completion of the crystal-growing process, Na is discharged from a crucible by a recovery device when the temperature of the crucible is 100° C. or higher, and is held in a holding vessel in a liquid state. The recovered Na can be drawn from the holding vessel via a faucet. Na remaining after completion of the crystal-growing process does not contain impurities of high vapor pressure, and is thus of high purity. Therefore, reuse, as flux, of the recovered Na enables manufacture of a Group III nitride semiconductor whose concentration of impurities is low.