Abstract: A p-type GaAs single crystal containing Si, Zn, B and In as dopants has an average dislocation density of 100 cm?2 or less. It may be produced by cooling a GaAs melt containing Si, Zn, B and In as dopants in a crystal-growing container having a seed crystal placed at a lower end thereof in an upward increasing temperature gradient, to cause a single crystal to grow upward from the seed crystal.

Abstract: A method for growing a compound semiconductor single crystal comprising cooling a starting material melt of a compound semiconductor with an upward increasing temperature gradient in a crystal-growing container having a seed crystal placed at a lower end, thereby growing a single crystal upward from the seed crystal, the crystal orientation of the seed crystal in a crystal growth axis direction being an offset orientation of <100>+?, wherein the offset angle ? is 2°???55°.

Abstract: A p-type GaAs single crystal containing Si, Zn, B and In as dopants has an average dislocation density of 100 cm−2 or less. It may be produced by cooling a GaAs melt containing Si, Zn, B and In as dopants in a crystal-growing container having a seed crystal placed at a lower end thereof in an upward increasing temperature gradient, to cause a single crystal to grow upward from the seed crystal.

Abstract: A method for growing a compound semiconductor single crystal comprising cooling a starting material melt of a compound semiconductor with an upward increasing temperature gradient in a crystal-growing container having a seed crystal placed at a lower end, thereby growing a single crystal upward from the seed crystal, the crystal orientation of the seed crystal in a crystal growth axis direction being an offset orientation of <100>+&thgr;, wherein the offset angle &thgr; is 2°≦&thgr;≦55°.

Abstract: An epitaxial semiconductor crystal plate or wafer capable of attaining increased reliability with enhanced luminance, a manufacturing method thereof, as well as a light-emitting diode (LED). It has been found that epitaxial wafers with enhanced illuminance and increased yield of manufacture can be fabricated by specifically arranging a double-heterostructure epitaxial wafer such that the interface between its p-type clad layer 2 and p-type GaAlAs active layer 3 and that between an n-type GaAlAs clad layer 4 and p-type GaAlAs active layer 3 measure 1×1017 cm−3 or less in oxygen concentration. Also, in order to cause the oxygen concentration near the p-type GaAlAs active layer 3 in layers of the epitaxial wafer to be less than or equal to 1×1017 cm−3, it may be preferable that a nondoped GaAs polycrystal for use as a preselected original material in liquid-phase epitaxial growth be less than or equal to 1×1016 cm−3 or there about.

Abstract: This invention relates to fabrication of a single crystal of a compound semiconductor according to the vertical Bridgman method which improves a recess in the interface between solid and melt and can obtain a stable yield of single crystal growth characterized in that a part for discharging the heat of a crucible to the outside in the radial direction is formed at least in a part in the circumferential direction of a heater part for controlling the interface between solid and melt in a heater which surrounds the crucible and a semiconductor melt is gradually solidified from a lower part to an upper part in the crucible while maintaining the interface between solid and melt in a saddle shape, thereby growing a single crystal.

Abstract: This invention relates to fabrication of a single crystal of a compound semiconductor according to the vertical Bridgman method which improves a recess in the interface between solid and melt and can obtain a stable yield of single crystal growth characterized in that a part for discharging the heat of a crucible to the outside in the radial direction is formed at least in a part in the circumferential direction of a heater part for controlling the interface between solid and melt in a heater which surrounds the crucible and a semiconductor melt is gradually solidified from a lower part to an upper part in the crucible while maintaining the interface between solid and melt in a saddle shape, thereby growing a single crystal.

Abstract: This invention relates to fabrication of a single crystal of a compound semiconductor according to the vertical Bridgman method which improves a recess in the interface between solid and melt and can obtain a stable yield of single crystal growth characterized in that a part for discharging the heat of a crucible to the outside in the radial direction is formed at least in a part in the circumferential direction of a heater part for controlling the interface between solid and melt in a heater which surrounds the crucible and a semiconductor melt is gradually solidified from a lower part to an upper part in the crucible while maintaining the interface between solid and melt in a saddle shape, thereby growing a single crystal.

Abstract: A Light-emitting diode having improved moisture resistance characteristics comprises a p-type gallium arsenide substrate and four epitaxial layers of Al.sub.x Ga.sub.1-x As (22, 23, 24 and 25). These epitaxial layers comprises an intervening layer (22) of p-type Al.sub.x1 Ga.sub.1-x1 As, a cladding layer (23) of p-type Al.sub.x2 Ga.sub.1-x2 As, an active layer (24) of Al.sub.x3 Ga.sub.1-x3 As, and a window layer (25) of Al.sub.x4 Ga.sub.1-x4 As so as to form a double-hetero structure, where x1, x2, x3 and x4 represent mixed crystal ratios of aluminum to arsenic of the layers, respectively, and meet the condition that:x2.gtoreq.x4>x1.gtoreq.x3 (0.ltoreq.x1, x2, x3, x4.ltoreq.1).

Abstract: An epitaxial semiconductor crystal plate or wafer capable of attaining increased reliability with enhanced luminance, a manufacturing method thereof as well as a light-emitting diode (LED). It has been found that epitaxial wafers with enhanced illuminance and increased yield of manufacture can be fabricated by specifically arranging a double-heterostructure epitaxial wafer such that the interface between its p-type clad layer 2 and p-type GaAlAs active layer 3 and that between an n-type GaAlAs clad layer 4 and p-type GaAlAs active layer 3 measure 1.times.10.sup.17 cm.sup.-3 or less in oxygen concentration. Also, in order to cause the oxygen concentration near the p-type GaAlAs active layer 3 in layers of the epitaxial wafer to be less than or equal to 1.times.10.sup.17 cm.sup.-3, it may be preferable that a nondoped GaAs polycrystal for use as a preselected original material in liquid-phase epitaxial growth be less than or equal to 1.times.10.sup.16 cm.sup.-3 or thereabout.

Abstract: A light-emitting diode having improved moisture resistance characteristics comprises a p-type gallium arsenide substrate and four epitaxial layers of Al.sub.x Ga.sub.1-x As (22, 23, 24 and 25). These epitaxial layers comprises an intervening layer (22) of p-type Al.sub.x Ga.sub.1-x As, a cladding layer (23) of p-type Al.sub.x2 Ga.sub.1-x2 As, an active layer (24) of Al.sub.x3 Ga.sub.1-x3 As, and a window layer (25) of Al.sub.x4 Ga.sub.1-x4 As so as to form a double-hetero structure, where x1, x2, x3 and x4 represent mixed crystal ratios of aluminum to arsenic of the layers, respectively, and meet the condition that:x2.gtoreq.x4>x1.gtoreq.x3 (0.ltoreq.x1, x2, x3, x4.ltoreq.1).

Abstract: A method of fabricating an undoped or impurity-doped semi-insulating GaAs single crystal with the use of a silica boat comprises the steps of making a melt of GaAs in the silica boat except for a seed crystal, doping the melt with oxygen, maintaining the doped melt as it is for a predetermined period of time, solidifying the melt from the side opposite the seed crystal toward the seed crystal, seeding the melt when the melt attains a predetermined melt zone width on the seed crystal side, and moving the melt zone in the direction opposite the seed crystal for its solidification while keeping the melt zone width unchanged.

Abstract: The present invention relates to the manufacturing process of semi-insulating gallium arsenide single crystal by pulling a seed crystal contacted with gallium arsenide melt which is obtained by heat-reacting gallium and arsenic in a crucible contained in a pressure container and is characteristic in providing a film layer of 8-20 mm thickness of melted boron oxide with less than 200 ppm water content under pressure controlled at 60 kg/cm.sup.2 and over during reaction and at 5-40 kg/cm.sup.2 during crystal growth in high purity inert gas atmosphere, and during said crystal growth, rotating said seed crystal and said crucible in the same direction, but said seed crystal being rotated 5-30 rpm faster than the said crucible, and setting the crystal growing plane of said seed crystal to be within .+-.3.degree. from {100} plane.