Abstract: The present invention suppresses anomalous growth of a Group III nitride semiconductor at the periphery of a seed substrate. The invention is directed to a method for producing a Group III nitride semiconductor including feeding a nitrogen-containing gas into a molten mixture of a Group III metal and a flux placed in a furnace, to thereby grow a Group III nitride semiconductor on a seed substrate. The oxygen concentration of the furnace internal atmosphere is elevated after the growth initiation temperature of the Group III nitride semiconductor has been achieved. In a period from the initiation of the growth to a certain timing, the oxygen concentration of the furnace internal atmosphere is controlled to 0.02 ppm or less, and thereafter, to greater than 0.02 ppm and 0.1 ppm or less.

Abstract: The present invention suppresses anomalous growth of a Group III nitride semiconductor at the periphery of a seed substrate. The invention is directed to a method for producing a Group III nitride semiconductor including feeding a nitrogen-containing gas into a molten mixture of a Group III metal and a flux placed in a furnace, to thereby grow a Group III nitride semiconductor on a seed substrate. The oxygen concentration of the furnace internal atmosphere is elevated after the growth initiation temperature of the Group III nitride semiconductor has been achieved. In a period from the initiation of the growth to a certain timing, the oxygen concentration of the furnace internal atmosphere is controlled to 0.02 ppm or less, and thereafter, to greater than 0.02 ppm and 0.1 ppm or less.

Abstract: The present invention reduces warpage of a Group III nitride semiconductor crystal in a method for producing a Group III nitride semiconductor crystal on a seed substrate through a flux method. A Group III nitride semiconductor is grown so that the total Al amount at the interface is not more than 3×1014/cm2, and the total Si amount at the interface is not more than 5×1014/cm2. Here, the total amount at the interface refers to a total number of atoms per unit area of an interface between the grown Group III nitride semiconductor and the seed substrate. Thus, warpage can be reduced by growing a Group III nitride semiconductor through a flux method.

Abstract: The seed substrate comprises a base substrate and a base layer comprising a Group III nitride semiconductor formed on the base substrate, which has a high dislocation density region and a low dislocation density region. The planar pattern of the high dislocation density region is a honeycomb pattern. A hollow exists between the base substrate and the low dislocation density region. The object layer is grown through a flux method using the seed substrate. The high dislocation density region is melted back at an initial stage of crystal growth, and thereafter, the object layer is grown on the top surface of the low dislocation density region. A cavity remains between the high dislocation density region and the object layer. The presence of the cavity and the hollow makes easy to peel the object layer from the seed substrate.

Abstract: To reduce ungrown region or abnormal grain growth region in growing a Group III nitride semiconductor through a flux method. A seed substrate has a structure in which a Group III nitride semiconductor layer is formed on a ground substrate as a base, and a mask is formed on the Group III nitride semiconductor layer. The mask has a plurality of dotted windows in an equilateral triangular lattice pattern. A Group III nitride semiconductor is grown through flux method on the seed substrate. Carbon is placed on a lid of a crucible holing the seed substrate and a molten mixture so that carbon is not contact with the molten mixture at the start of crystal growth. Thereby, carbon is gradually added to the molten mixture as time passes. Thus, ungrown region or abnormal grain growth region is reduced in the Group III nitride semiconductor crystal grown on the seed substrate.

Abstract: The seed substrate comprises a base substrate and a base layer comprising a Group III nitride semiconductor formed on the base substrate, which has a high dislocation density region and a low dislocation density region. The planar pattern of the high dislocation density region is a honeycomb pattern. A hollow exists between the base substrate and the low dislocation density region. The object layer is grown through a flux method using the seed substrate. The high dislocation density region is melted back at an initial stage of crystal growth, and thereafter, the object layer is grown on the top surface of the low dislocation density region. A cavity remains between the high dislocation density region and the object layer. The presence of the cavity and the hollow makes easy to peel the object layer from the seed substrate.

Abstract: To reduce ungrown region or abnormal grain growth region in growing a Group III nitride semiconductor through a flux method. A seed substrate has a structure in which a Group III nitride semiconductor layer is formed on a ground substrate as a base, and a mask is formed on the Group III nitride semiconductor layer. The mask has a plurality of dotted windows in an equilateral triangular lattice pattern. A Group III nitride semiconductor is grown through flux method on the seed substrate. Carbon is placed on a lid of a crucible holing the seed substrate and a molten mixture so that carbon is not contact with the molten mixture at the start of crystal growth. Thereby, carbon is gradually added to the molten mixture as time passes. Thus, ungrown region or abnormal grain growth region is reduced in the Group III nitride semiconductor crystal grown on the seed substrate.

Abstract: A method for producing a Group III nitride semiconductor single crystal, includes forming a mask layer on an underlayer, to thereby form a seed crystal in which a portion of the underlayer is covered with the mask layer and in which the remaining portion of the underlayer is not covered with the mask layer, etching the remaining portion, and growing a Group III nitride semiconductor single crystal on the seed crystal.

Abstract: The present invention provides a method for producing a Group III nitride semiconductor single crystal having excellent crystallinity, and a method for producing a GaN substrate having excellent crystallinity, the method including controlling melting back. Specifically, a mask layer is formed on a GaN substrate serving as a growth substrate. Then, a plurality of trenches which penetrate the mask layer and reach the GaN substrate are formed through photolithography. The obtained seed crystal and raw materials of a single crystal are fed to a crucible and subjected to treatment under pressurized and high temperature conditions. Portions of the GaN substrate exposed to the trenches undergo melting back with a flux. Through dissolution of the GaN substrate, the dimensions of the trenches increase, to provide large trenches. The GaN layer is grown from the surface of the mask layer as a starting point.

Abstract: The present invention provides a semiconductor crystal removal apparatus which realizes effective removal of a semiconductor crystal from a crucible through rapid melting of a solidified flux, and a method for producing a semiconductor crystal. The semiconductor crystal removal apparatus includes a crucible support for supporting a crucible so that the opening of the crucible is directed downward; a heater for heating the crucible supported on the crucible support; and a semiconductor crystal receiving net for receiving a semiconductor crystal falling from the opening of the crucible. The semiconductor crystal removal apparatus further includes a determination portion for determining removal of the semiconductor crystal on the basis of a change in weight through falling of the semiconductor crystal.

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: A method for producing a Group III nitride semiconductor includes reacting a molten mixture containing at least a Group III element and an alkali metal with a gas containing at least nitrogen, to thereby grow a Group III nitride semiconductor crystal on the seed crystal. The method includes forming a template substrate including a sapphire substrate and a first Group III nitride semiconductor layer as the seed crystal which is formed by vapor phase growth and which includes a c-plane as a main plane is employed, and the template substrate is placed and maintained in the molten mixture under conditions where crystal growth of the Group III nitride semiconductor is inhibited, to thereby partially melt back a plurality of separated parts of the first Group III nitride semiconductor layer to such a depth that the sapphire substrate is partially exposed.

Abstract: Objects of the present invention are to provide a method for producing a Group III nitride semiconductor single crystal, which method enables production of a Group III nitride semiconductor single crystal having a flat surface by means of a crucible having any inside diameter; to provide a self-standing substrate obtained from the Group III nitride semiconductor single crystal; and to provide a semiconductor device employing the self-standing substrate. The production method includes adding the template, a flux, and semiconductor raw materials to a crucible and growing a Group III nitride semiconductor single crystal while the crucible is rotated. In the growth of the semiconductor single crystal, the crucible having an inside diameter R (mm) is rotated at a maximum rotation speed ? (rpm) satisfying the following conditions: ?1?4????1+4; ?1=10z; and z=?0.78×log10(R)+3.1.

Abstract: A method of producing a light-emitting semiconductor device of a group III nitride compound includes forming a buffer layer on a sapphire substrate, forming a Si-doped N+-layer with supplying silane, the N+-layer satisfying 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 formula Alx1Gay1In1-x1-y1N, where 0?x1?1, 0?y1?1, and 0?x1+y1?1, on the N+-layer, and forming a P-layer of a P-type conduction on the emission layer, the P-layer including aluminum gallium nitride satisfying formula Alx2Ga1-x2N, wherein 0?x2?1.

Abstract: Objects of the present invention are to provide a method for producing a Group III nitride semiconductor single crystal, which method enables production of a Group III nitride semiconductor single crystal having a flat surface by means of a crucible having any inside diameter; to provide a self-standing substrate obtained from the Group III nitride semiconductor single crystal; and to provide a semiconductor device employing the self-standing substrate. The production method includes adding the template, a flux, and semiconductor raw materials to a crucible and growing a Group III nitride semiconductor single crystal while the crucible is rotated. In the growth of the semiconductor single crystal, the crucible having an inside diameter R (mm) is rotated at a maximum rotation speed ? (rpm) satisfying the following conditions: ?1?4????1+4; ?1=10z; and z=?0.78×log10(R)+3.1.

Abstract: The present invention provides a semiconductor crystal removal apparatus which realizes effective removal of a semiconductor crystal from a crucible through rapid melting of a solidified flux, and a method for producing a semiconductor crystal. The semiconductor crystal removal apparatus includes a crucible support for supporting a crucible so that the opening of the crucible is directed downward; a heater for heating the crucible supported on the crucible support; and a semiconductor crystal receiving net for receiving a semiconductor crystal falling from the opening of the crucible. The semiconductor crystal removal apparatus further includes a determination portion for determining removal of the semiconductor crystal on the basis of a change in weight through falling of the semiconductor crystal.

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: In the production of GaN through the flux method, deposition of miscellaneous crystals on the nitrogen-face of a GaN self-standing substrate and waste of raw materials are prevented. Four arrangements of crucibles and a GaN self-standing substrate are exemplified. In FIG. 1A, a nitrogen-face of a self-standing substrate comes into close contact with a sloped flat inner wall of a crucible. In FIG. 1B, a nitrogen-face of a self-standing substrate comes into close contact with a horizontally facing flat inner wall of a crucible, and the substrate is fixed by means of a jig. In FIG. 1C, a jig is provided on a flat bottom of a crucible, and two GaN self-standing substrates are fixed by means of the jig so that the nitrogen-faces of the substrates come into close contact with each other. In FIG. 1D, a jig is provided on a flat bottom of a crucible, and a GaN self-standing substrate is fixed on the jig so that the nitrogen-face of the substrate is covered with the jig.

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