Abstract: There are provided a semiconductor substrate and a semiconductor laser using the semiconductor substrate which promises smooth and optically excellent cleaved surfaces and is suitable for fabricating semiconductor lasers using nitride III-V compound semiconductors. Using a semiconductor substrate, such as GaN substrate, having a major surface substantially normal to a {0001}-oriented face, e.g. {01-10}-oriented face or {11-20}-oriented face, or offset within ±5° from these faces, nitride III-V compound semiconductor layers are epitaxially grown on the substrate to form a laser structure. To make cavity edges, the GaN substrate is cleaved together with the overlying III-V compound semiconductor layers along high-cleavable {0001}-oriented faces.

Abstract: When nitride series III-V group compound semiconductor is manufactured by gas phase growing using starting material for a group III element, ammonia as a starting material for a group V element and hydrogen, the gas phase molar ratio of hydrogen to the total amount of hydrogen and ammonia (H2/(H2+NH3)) is specified to 0.3<(H2/(H2+NH3))<0.7, 0.3<(H2/(H2+NH3))<0.6 or 0.4<(H2/(H2+NH3))<0.5. A nitride series III-V group compound semiconductor can thus be manufactured with less non-emission center and of excellent crystallinity.

Abstract: When nitride series III-V group compound semiconductor is manufactured by gas phase growing using starting material for a group III element, ammonia as a starting material for a group V element and hydrogen, the gas phase molar ratio of hydrogen to the total amount of hydrogen and ammonia (H2/(H2+NH3)) is specified to 0.3<(H2/(H2+NH3))<0.7, 0.3<(H2/(H2+NH3))<0.6 or 0.4<(H2/(H2+NH3))<0.5. A nitride series III-V group compound semiconductor can thus be manufactured with less non-emission center and of excellent crystallinity.

Abstract: A semiconductor laser, a semiconductor device and a nitride series III-V group compound substrate capable of obtaining a crystal growth layer with less fluctuation of the crystallographic axes and capable of improving the device characteristics, as well as a manufacturing method therefor are provided. The semiconductor laser comprises, on one surface of a substrate used for growing, a plurality of spaced apart seed crystal layers and an n-side contact layer having a lateral growing region which is grown on the basis of the plurality of seed crystal layers. The seed crystal layer is formed in that a product of width w1 (unit: &mgr;m) at the boundary thereof relative to the n-side contact layer along the arranging direction A and a thickness t1 (unit: &mgr;m) along the direction of laminating the n-side contact layer is 15 or less.

Abstract: A light emitting device which can be easily manufactured and can control the positions of light emission precisely, and an optical device. A first and second light emitting elements are formed on one face of a supporting base. The first light emitting element has an active layer made of GaInN mixed crystal on a GaN-made first substrate on the side thereof on which the supporting base is disposed. The second light emitting element has lasing portions on a GaAs-made second substrate on the side thereof on which the supporting base is disposed. Since the first and second light emitting elements are not grown on the same substrate, a multiple-wavelength laser having the output wavelength of around 400 nm can be easily obtained. Since the first substrate is transparent in the visible region, the positions of light emitting regions in the first and second light emitting elements can be precisely controlled by lithography.

Abstract: A semiconductor device such as a light emitting semiconductor device comprising a mask layer having opening areas and a selective growing layer comprising a semiconductor grown selectively by way of the mask layer, with each of the mask layer and the selective growing layer being disposed by two or more layers alternately. The semiconductor device is manufactured by a step of laminating on a substrate a mask layer having opening areas and a selective growing layer comprising a semiconductor grown selectively way of a mask layer, each by two or more layers alternately and a subsequent step of laminating semiconductor layers thereon. Threading dislocations in the underlying layer are interrupted by the first mask layer and the second mask layer and do not propagate to the semiconductor layer. The density of the threading dislocations is lowered over the entire surface and the layer thickness can be reduced.

Abstract: To provide a semiconductor device capable of preventing the bowing of the substrate, and having a semiconductor layer of a III-V group compound of a nitride system with excellent crystallinity.

Abstract: To provide a semiconductor device capable of enhancing crystallinity of a semiconductor of a III-V group compound of a nitride system formed on a sapphire substrate and to provide a method of manufacturing the same.

Abstract: A semiconductor device such as a light emitting semiconductor device comprising a mask layer having opening areas and a selective growing layer comprising a semiconductor grown selectively by way of the mask layer, with each of the mask layer and the selective growing layer being disposed by two or more layers alternately. The semiconductor device is manufactured by a step of laminating on a substrate a mask layer having opening areas and a selective growing layer comprising a semiconductor grown selectively way of a mask layer, each by two or more layers alternately and a subsequent step of laminating semiconductor layers thereon. Threading dislocations in the underlying layer are interrupted by the first mask layer and the second mask layer and do not propagate to the semiconductor layer. The density of the threading dislocations is lowered over the entire surface and the layer thickness can be reduced.

Abstract: A method for fabricating nitride III-V compound semiconductor layers of substrate, of GaN for example, comprises the steps of: growing a first B.sub.w Al.sub.x Ga.sub.y In.sub.z N layer 2 (where 0.ltoreq.w.ltoreq.1, 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.y.ltoreq.1 and w+x+y+z=1) on a sacrificial sapphire substrate 1 by MOCVD at a growth rate not higher than 4 .mu.m/h; growing a second B.sub.w Al.sub.x Ga.sub.y In.sub.z N layer 3 (where 0.ltoreq.w.ltoreq.1, 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.y.ltoreq.1 and w+x+y+z=1) on the first B.sub.w Al.sub.x Ga.sub.y In.sub.z N layer by hydride VPE at a growth rate higher than 4 .mu.m/h and not higher than 200 .mu.m/h; and removing the sacrificial substrate 1.

Abstract: A molecular beam epitaxy system having a plurality of chambers which contain at least a first chamber and a second chamber. The first chamber is used to form II-VI column compound semiconductor layers not containing Te. The second chamber is used to form II-VI column compound semiconductor layers containing at least Te. A semiconductor device having an ohmic characteristics can be fabricated without mixing Te into other layers.

Abstract: A semiconductor light emitting device composed of an n-type cladding layer, an n-type guide layer, an active layer, a p-type guide layer, and a p-type cladding layer which are sequentially laminated on a substrate. The p-type guide layer is formed from ZnSSe mixed crystal doped with nitrogen. That side of the p-type guide layer which is adjacent to the p-type cladding layer is a p-type semiconductor region in which the concentration of nitrogen is 2.times.10.sup.17 cm.sup.-3, and that side adjacent to the active layer is an intrinsic semiconductor region. The p-type cladding layer is formed from ZnMgSSe mixed crystal doped with nitrogen. That side of the p-type cladding layer which is adjacent to the p-type guide layer is the low-concentration region in which the concentration of nitrogen is 1.times.10.sup.17 cm.sup.-3 which is lower than the concentration at which the rate of activation begins to decrease. The opposite side is the high-concentration region in which the concentration of nitrogen os 2.times.

Abstract: The semiconductor light emitting device includes a semiconductor substrate (1), a first conductivity type first cladding layer (2) deposited on the semiconductor substrate (1), an active layer (4) deposited on the first cladding layer (2), and the second conductivity type second cladding layer (6) deposited on the active layer (4). The first and the second cladding layers (2, 6) are made of the II/VI-compound semiconductors including at least one kind of II group elements such as Zn, Hg, Cd, Mg and at least one kind of VI group elements such as S, Se, Te. The lattice mismatching .DELTA.a/a (%) between at least one of the first cladding layer (2) and the second cladding layer (6) and the substrate is set within the range of -0.9%.ltoreq..DELTA.a/a.ltoreq.0.5% (reference symbols a and a.sub.c represent the lattice constant of the semiconductor substrate and the lattice constant of at least either of the first and second cladding layers, and .DELTA.a is obtained from .DELTA.a=a.sub.c -a).

Abstract: A film of a II-VI group compound semiconductor of at least one of elements belonging to the II group of the periodic table and at least one of elements belonging to the VI group of the periodic table is deposited on a substrate. When the film is deposited on the substrate, a plasma of nitrogen in an excited state is applied to the substrate while removing charged particles from said plasma by a charged particle removing means. The deposited film of a nitrogen-doped II-VI group compound semiconductor has an increased percentage of activated nitrogen atoms and improved crystallinity.

Abstract: A method for growing a II-VI compound semiconductor layer containing Cd, such as Zn.sub.1-x Cd.sub.x Se, by a molecular beam epitaxy method is disclosed. During the growth, the ratio of the intensity of molecular beams of a group VI element to the intensity of molecular beams of a group II element in terms of intensities of molecular beams actually irradiated onto a substrate, namely, the substantial VI/II ratio, is controlled preferably in the range from 0.7 to 1.3, to increase the Cd incorporating efficiency into the grown layer sufficiently high.

Abstract: By applying the method, the critical film thickness of a compound semiconductor layer is determined, and a semiconductor device having a compound semiconductor layer with an optimized film thickness excellent in emitting performance is manufactured.The relationship between film thickness of a compound semiconductor layer and photoluminescence (PL) corresponding to the film thickness is obtained by measurement, the film thickness where PL exhibits a peak is designated as critical film thickness. The semiconductor layer comprises II-VI group compound semiconductor layer containing at least cadmium. The relationship between the critical film thickness and cadmium composition ratio is obtained by measurement. An equation which approximates the relationship between the critical film thickness and cadmium composition ratio is formulated.

Abstract: The semiconductor light emitting device includes a semiconductor substrate (1), a first conductivity type first cladding layer (2) deposited on the semiconductor substrate (1), an active layer (4) deposited on the first cladding layer (2), and the second conductivity type second cladding layer (6) deposited on the active layer (4). The first and the second cladding layers (2, 6) are made of the II/VI-compound semiconductors including at least one kind of group II elements such as Zn, Hg, Cd, Mg and at least one kind of group VI elements such as S, Se, Te. The lattice mismatching .DELTA.a/a (%) between at least one of the first cladding layer (2) and the second cladding layer (6) and the substrate is set within the range of -0.9%.ltoreq..DELTA.Aa/a.ltoreq.0.5% (reference symbols a and a.sub.c represent the lattice constant of the semiconductor substrate and the lattice constant of at least either of the first and second cladding layers, and .DELTA.a is obtained from .DELTA.a=a.sub.c -a).

Abstract: Crystals of an amino acid, a nucleic acid or a derivative thereof can be efficiently isolated and purified at low cost from a solution containing the crystals, bacterial cells and medium components by using a liquid cyclone.

Abstract: Disclosed is a semi-solid pharmaceutical agent containing a stabilized proteinaceous bioactive substance prepared by successively mixing an oligosaccharide and an aqueous solution of a proteinaceous bioactive substance, and kneading the resultant solids with an oil or fat base. The pharmaceutical handles with ease because it is readily administered to the body through percutaneous and permucosal route which are safer and less in pain administration routes than other conventional administrations.

Abstract: According to the present invention, a p-type ZnSe or p-type ZnSSe buffer layer is formed on a p-type GaAs substrate through at least single layer made of AlGaInP-based material and a II/VI-compound laser structure is formed on the p-type ZnSe or p-type ZnSSe buffer layer. Further, an AlGaAs-based buffer layer is provided between the substrate and the AlGaInP-based buffer layer. Further, the AlGaAs-based buffer layer has a composition expressed as Al.sub.0.5 Ga.sub.0.4 As and the AlGaInP-based buffer layer has a composition expressed as Al.sub.0.5 In.sub.0.5 P. Furthermore, a composition ratio x of Al in a buffer layer expressed as Al.sub.x Ga.sub.1-x As is modulated from 0 to 0.6 and a composition ratio y of Al in a buffer layer expressed as (Al.sub.y Ga.sub.1-y).sub.0.5 In.sub.0.5 P is modulated from 0 to 1. According to the present invention, an operation voltage of the II/VI-compound semiconductor laser can be reduced and the green or blue color semiconductor laser of low operation voltage can be obtained.