Abstract: A method for fabricating a III-V Group compound semiconductor comprising a step of epitaxially growing on an AlxGa1-xAs layer of lower Al content an AlxGa1-xAs layer of higher Al content, in which step a growth rate of the AlxGa1-xAs layer of higher Al content is made slower than a growth rate of the AlxGa1-xAs layer of lower Al content, thereby effectively inhibiting the occurrence of starting points of abnormal growth at the interface between the two layers.

Abstract: Provided is a method for fabricating a compound semiconductor multilayer epitaxial substrate comprising a plurality of epitaxial layers, comprising the steps of determining at least one of the thickness, impurity concentration, and composition of an epitaxial layer comprising the multilayer epitaxial substrate by theoretical calculation, the theoretical calculation describing on electric field and charge distribution inside the epitaxial layer, and performing epitaxy of the epitaxial layer according to the theoretical calculation of the thickness, impurity concentration and/or composition of the epitaxial layer so that measurable electric characteristics of the substrate predetermined by the calculation are satisfied. The method can reduce the fabrication process and also can be applied to manufacture a multilayer epitaxial substrate having a unique structure.

Abstract: A 3-5 group compound semiconductor comprising a conductive substrate and a device layer of a 3-5 group compound semiconductor formed by epitaxial growth on said conductive substrate, which comprises between said conductive substrate and said device layer a pn laminate structure layer having at least one pn junction comprising a p-type layer having p-type conductivity and an n-type layer having n-type conductivity.

Abstract: A thin-film crystal wafer having a pn junction includes a first crystal layer of p GaAs, a second crystal layer of n InxAlyGa1-x-yP, the first and second crystal layers being lattice-matched layers that form a heterojunction, and a control layer of a thin-film of InxAlyGa1-x-yP differing in composition from the n InxAlyGa1-x-yP of the second crystal layer is formed at the interface of the heterojunction. The control layer enables the energy discontinuity at the interface of the InxAlyGa1-x-yP/GaAs heterojunction to be set within a relatively broad range of values and thus enables the current amplification factor and the offset voltage to be matched to specification values by varying the energy band gap at the heterojunction.

Abstract: A method for fabricating a III-V Group compound semiconductor comprising a step of epitaxially growing on an AlxGa1−xAs layer of lower Al content an AlxGa1−xAs layer of higher Al content, in which step a growth rate of the AlxGa1−xAs layer of higher Al content is made slower than a growth rate of the AlxGa1−xAs layer of lower Al content, thereby effectively inhibiting the occurrence of starting points of abnormal growth at the interface between the two layers.

Abstract: Provided is a 3-5 group compound semiconductor comprising a GaAs substrate, a buffer layer on said GaAs substrate and an epitaxial crystal layer on said buffer layer, and the dislocation density in the epitaxial crystal layer on said buffer layer is 2000/cm2 or less. The properties and reliability of an electronic device or optical device can be remarkably improved.

Abstract: Provided is a method for fabricating a compound semiconductor multilayer epitaxial substrate comprising a plurality of epitaxial layers, comprising the steps of determining at least one of the thickness, impurity concentration, and composition of an epitaxial layer comprising the multilayer epitaxial substrate by theoretical calculation, the theoretical calculation describing on electric field and charge distribution inside the epitaxial layer, and performing epitaxy of the epitaxial layer according to the theoretical calculation of the thickness, impurity concentration and/or composition of the epitaxial layer so that measurable electric characteristics of the substrate predetermined by the calculation are satisfied. The method can reduce the fabrication process and also can be applied to manufacture a multilayer epitaxial substrate having a unique structure.

Abstract: Provided is a manufacturing method of a compound semiconductor having at least one layer of carbon-doped p-type semiconductor epitaxial layer by a MOVPE process, wherein carbon trichloride bromide is used as a carbon source of carbon to be added to the p-type semiconductor epitaxial layer. In the method the etching amount during growth is relatively small, and carbon can be added to a high concentration even with a large MOVPE apparatus.

Abstract: A semiconductor comprising an n-type semiconductor layer 1 with donor impurities added thereto, a semiconductor layer 2 having the value of energy from vacuum level to Fermi level larger than the value of energy from vacuum level to the lower end of the conduction band of the n-type semiconductor 1 and a junction connected to said semiconductor layer 2, characterized in that the donor impurities concentration (N.sub.d) in the range of thickness of the depletion layer generated in said n-type semiconductor layer 1 in contact with the junction boundary is at least2.7.times.10.sup.3 exp{-5.5(E.sub.C -E.sub.FS)}.times.N.sub.C(where E.sub.C is the energy value in eV from the upper end of the valence band to the lower end of the conduction band of the n-type semiconductor 1, E.sub.FS is the energy value in eV from the upper end of the valence band to the charge neutrality level of the n-type semiconductor 1, and N.sub.C is the effective density of states in cm.sup.

Abstract: A process for crystal growth of III-V group compound semiconductor, which comprises pyrolyzing, in a gas phase, a material consisting of an organometallic compound and/or a hydride in the presence of an organic compound containing an oxygen atom-carbon atom direct bond, used as a dopant to grow a III-V group compound semiconductor crystal layer containing at least aluminum, of high electric resistance. Said process can grow a compound semiconductor layer of high electric resistance by the use of a dopant which enables the independent controls of oxygen concentration and aluminum concentration and which has a small effect of oxygen remaining.

Abstract: A semiconductor epitaxial substrate, characterized in that a crystal is formed by epitaxial growth on a gallium arsenide single crystal substrate whose crystallographic plane azimuth is slanted from that of one of {100} planes at an angle of not more than 1.degree., that at least part of the epitaxial crystal is an In.sub.x Ga.sub.(1-x) As crystal (wherein 0<x<1), and that the epitaxial growth is carried out by chemical vapor deposition. Since the In.sub.x Ga.sub.(1-x) As layer has reduced microscopic unevenness and reduced variation in thickness, the epitaxial substrate of the present invention can be used as a channel layer of a field effect transistor or as an active layer of a semiconductor laser to endow these devices with excellent characteristics.

Abstract: A semiconductor epitaxial substrate and a process for producing the same, the semiconductor epitaxial substrate comprising a GaAs single-crystal substrate having thereon an In.sub.y Ga.sub.(1-y) As (0<y.ltoreq.1) crystal layer as a channel layer, the composition and the thickness of the In.sub.y Ga.sub.(1-y) As layer being in the ranges within the elastic deformation limit of crystals constituting the In.sub.y Ga.sub.(1-y) As layer and the vicinity of the In.sub.y Ga.sub.(1-y) As layer, the semiconductor epitaxial substrate further comprising a semiconductor layer between the channel layer and an electron donating layer for supplying electrons to the channel layer, the semiconductor layer having a thickness of from 0.5 to 5 nm and a bandgap width within the range of from the bandgap width of GaAs to the bandgap width of the electron donating layer.

Abstract: An epitaxially grown compound-semiconductor crystal comprising a substrate, a buffer layer formed directly or indirectly on the substrate, and an active layer formed on the buffer layer. The buffer layer comprises (A) a high-resistivity AlGaAs or AlGaInP layer doped with oxygen or/and a transition metal and, formed thereon, (B) a layer consisting of high-purity GaAs, InGaP, or AlGaAs.

Abstract: A vapor-phase epitaxial growth method for producing a Groups III-V compound semiconductor containing arsenic by vapor-phase epitaxial growth using arsenic trihydride as an arsenic source is disclosed, wherein said arsenic trihydride has a volatile impurity concentration of not more than 1.5 molppb on a germanium tetrahydride conversion. The resulting epitaxial crystal has a low residual carrier concentration and is applicable to a field effect transistor.

Abstract: In an apparatus for vapor-phase growth which comprises a reactor having an inlet for the introduction of the gas containing a source material on its top and a susceptor provided in the downstream portion of the reactor, the improvement wherein the susceptor is generally in a conical or polygonal pyramid form consisting of an upper rectifying portion and a lower substrate holding portion, with the diameter of the susceptor in its lower portion increasing by a greater degree than in its upper portion.

Abstract: A warp-knit stringer tape for a slide fastener comprises an elongate first web for supporting along one longitudinal edge thereof a row of fastener coupling elements, an elongate second web spaced transversely from the first web with a wale-free coarse region therebetween which is remote from the coupling-element-supporting side of the first web, and a connector thread interconnecting the first and second webs across the wale-free coarse region. The second web is double knit as a round braid-like structure which is compact and rigid.

Abstract: A separable slide fastener comprises a pair of warp-knit stringer tapes each having a pair of webs with a wale-free region therebetween, which are interconnected by a connector thread extending across the wale-free region at longitudinal intervals, the wale-free region being receptive of a chain of thread loops for attaching the stringer tape to a fabric. A pair of rows of coupling elements is mounted on opposite longitudinal edges of the stringer tapes and taken into and out of interdigitating engagement by a slider movable along the rows of coupling elements. The stringer tapes have at one end thereof a separable bottom end stop. A reinforcement member is mounted on each of the stringer tapes at the one end thereof and connected to the separable bottom end stop.