Abstract: The present invention provides a method for producing a Group III nitride compound semiconductor crystal, the semiconductor crystal being grown through the flux method employing a flux. At least a portion of a substrate on which the semiconductor crystal is to be grown is formed of a flux-soluble material. While the semiconductor crystal is grown on a surface of the substrate, the flux-soluble material is dissolved in the flux from a surface of the substrate that is opposite the surface on which the semiconductor crystal is grown. Alternatively, after the semiconductor crystal has been grown on a surface of the substrate, the flux-soluble material is dissolved in the flux from a surface of the substrate that is opposite the surface on which the semiconductor crystal has been grown. The flux-soluble material is formed of silicon.

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: 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: 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 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: 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 Group III nitride compound semiconductor crystal, the semiconductor crystal being grown through the flux method employing a flux. At least a portion of a substrate on which the semiconductor crystal is to be grown is formed of a flux-soluble material. While the semiconductor crystal is grown on a surface of the substrate, the flux-soluble material is dissolved in the flux from a surface of the substrate that is opposite the surface on which the semiconductor crystal is grown. Alternatively, after the semiconductor crystal has been grown on a surface of the substrate, the flux-soluble material is dissolved in the flux from a surface of the substrate that is opposite the surface on which the semiconductor crystal has been grown. The flux-soluble material is formed of silicon.

Abstract: The back surface of a semiconductor crystal substrate 102 which has a thickness of about 150 ?m and is made of undoped GaN bulk crystal consists of a polished plane 102a which is flattened through dry-etching and a grinded plane 102b which is formed in a taper shape and is flattened through dry-etching. On about 10 nm in thickness of GaN n-type clad layer (low carrier concentration layer) 104, about 2 nm in thickness of Al0.005In0.045Ga0.95N well layer 51 and about 18 nm in thickness of Al0.12Ga0.88N barrier layer 52 are deposited alternately as an active layer 105 which emits ultraviolet light and has MQW structure comprising 5 layers in total. Before forming a negative electrode (n-electrode c) on the polished plane of the semiconductor substrate a, the polished plane is dry-etched.

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 Group III nitride compound semiconductor, which method permits only minimal reaction of the semiconductor with a hetero-substrate during epitaxial growth and induces no cracks in the Group III nitride compound semiconductor even when the semiconductor is cooled to room temperature. The method includes a buffer layer formation step for forming a gas-etchable buffer layer on the hetero-substrate, and a semiconductor formation step for epitaxially growing the Group III nitride compound semiconductor on the buffer layer through a vapor phase growth method, wherein at least a portion of the buffer layer is gas-etched during or after the semiconductor formation step.

Abstract: A light-emitting semiconductor device provides an active layer which comprises thirteen (13) layers that includes six (6) pairs of quantum barrier layers made of Al0.95In0.05N and quantum well layers made of Al0.70In0.30N, which are laminated together alternately. The semiconductor device may also comprise a quantum well layer having a high composition ratio of indium (In). Forming the quantum barrier layer and the quantum well layer to have a high composition ratio of indium (In) increases the lattice constant of the active layer of the semiconductor device.

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: When a substrate layer (desired semiconductor crystal) made of a group III nitride compound is grown on a base substrate comprising a lot of projection parts, a cavity in which a semiconductor crystal is not deposited may be formed between each projection part although it depends on conditions such as the size of each projection part, arranging interval between each projection part and crystal growth. So when the thickness of the substrate layer is sufficiently larger compared with the height of the projection part, inner stress or outer stress become easier to act intensively to the projection part. As a result, such stress especially functions as shearing stress toward the projection part. When the shearing stress becomes larger, the projection part is ruptured. So utilizing the shearing stress enables to separate the base substrate and the substrate layer easily.

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: Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (AlxGa1?xN) in which the n-layer of n-type gallium nitride compound semiconductor (AlxGa1?xN) is of double-layer structure including an n-layer of low carrier concentration and an n+-layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (AlxGa1?xN); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an iL-layer of low impurity concentration containing p-type impurities in comparatively low concentration and an iH-layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semiconductor (AlxGa1?xN) ha

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: Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (AlxGa1−xN) in which the n-layer of n-type gallium nitride compound semiconductor (AlxGa1−xN) is of double-layer structure including an n-layer of low carrier concentration and an n+-layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (AlxGa1−xN); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an iL-layer of low impurity concentration containing p-type impurities in comparatively low concentration and an iH-layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semic

Abstract: When a substrate layer (desired semiconductor crystal) made of a group III nitride compound is grown on a base substrate comprising a lot of projection parts, a cavity in which a semiconductor crystal is not deposited may be formed between each projection part although it depends on conditions such as the size of each projection part, arranging interval between each projection part and crystal growth. So when the thickness of the substrate layer is sufficiently larger compared with the height of the projection part, inner stress or outer stress become easier to act intensively to the projection part. As a result, such stress especially functions as shearing stress toward the projection part. When the shearing stress becomes larger, the projection part is ruptured. So utilizing the shearing stress enables to separate the base substrate and the substrate layer easily.

Abstract: Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (AlXGa1-xN) in which the n-layer of n-type gallium nitride compound semiconductor (AlxGa1-XN) is of double-layer structure including an n-layer of low carrier concentration and an n+-layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (AlxGa1-xN); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an iL-layer of low impurity concentration containing p-type impurities in comparatively low concentration and an iH-layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semiconductor (AlxGa1-x

Abstract: Disclosed herein are (1) a light-emitting semiconductor device that uses a gallium nitride compound semiconductor (AlxGa1−xN) in which the n-layer of n-type gallium nitride compound semiconductor (AlxGa1−xN) is of double-layer structure including an n-layer of low carrier concentration and an n+-layer of high carrier concentration, the former being adjacent to the i-layer of insulating gallium nitride compound semiconductor (AlxGa1−xN); (2) a light-emitting semiconductor device of similar structure as above in which the i-layer is of double-layer structure including an iL-layer of low impurity concentration containing p-type impurities in comparatively low concentration and an iH-layer of high impurity concentration containing p-type impurities in comparatively high concentration, the former being adjacent to the n-layer; (3) a light-emitting semiconductor device having both of the above-mentioned features and (4) a method of producing a layer of an n-type gallium nitride compound semic