Abstract: In a semiconductor laser element: an n-type cladding layer, an undoped or n-type optical waveguide layer, an Inx3Ga1-x3As1-y3Py3 quantum-well active layer, and an undoped or p-type optical waveguide layer are formed on an n-type GaAs substrate; a first etching stop layer and an n-type first current confinement layer are formed corresponding to high-refractive-index regions realizing an ARROW structure; a second etching stop layer and an n-type second current confinement layer are formed with an opening for current injection; and a p-type cladding layer and a p-type GaAs contact layer are formed over the entire upper surface. For example, the compositions of the cladding layers, the optical waveguide layers, the first etching stop layer, the first current confinement layer, the second etching stop layer, and the second current confinement layer are In0.49Ga0.51P (or Alz1Ga1-z1As), GaAs, p-type Inx8Ga1-x8P, GaAs, n-type or p-type Inx8Ga1-x8P, and Alz1Ga1-z1As, respectively.

Abstract: In a semiconductor laser device: an n-type In0.49Ga0.51P cladding layer, an undoped or n-type Inx1Ga1-x1As1-y1Py1 optical waveguide layer, an Inx3Ga1-x3As1-y3Py3 compressive-strain quantum-well active layer, an undoped or p-type Inx1Ga1-x1As1-y1Py1 optical waveguide layer, a p-type In0.49Ga0.51P cladding layer, and a p-type GaAs etching stop layer are formed on an n-type GaAs substrate; a p-type Inx8Ga1-x8P etching stop layer and an n-type GaAs current confinement layer are formed corresponding to high-refractive-index regions which realize an ARROW structure; a p-type Inx9Ga1-x9P etching stop layer is formed over the n-type GaAs current confinement layer and exposed areas of the first etching stop layer; a p-type GaAs etching stop layer and an n-type In0.49Ga0.51P current confinement layer are formed in regions other than a current injection region; and a p-type In0.49Ga0.51P cladding layer and a p-type GaAs contact layer are formed over the entire upper surface.

Abstract: A pattern forming method has the steps of: forming a pattern by discharging droplets of a conductive material forming solution onto an insulating substrate; forming a conductive layer pattern on the pattern by discharging droplets of a solution which becomes a growth core; and forming a metal pattern by immersing the conductive layer pattern in a plating liquid. The pattern forming method may further have the step of forming a protective layer on a surface of the metal pattern by discharging droplets of an insulating material forming solution except at regions which are to become electrodes of the metal pattern.

Abstract: In a semiconductor laser element: an n-type AlxGa1−x As cladding layer, an undoped or n-type In0.49Ga0.51P optical waveguide layer, an Inx1Ga1−x1As1−y1Py1 compressive-strain quantum-well active layer, an undoped or p-type In0.49Ga0.51P optical waveguide layer, and a p-type GaAs etching stop layer are formed on an n-type GaAs substrate; a p-type Inx8Ga1−x8P etching stop layer and an n-type GaAs current confinement layer are formed corresponding to high-refractive-index regions which realize an ARROW structure; a p-type Inx9Ga1−x9P etching stop layer is formed over the n-type GaAs current confinement layer and exposed areas of the first etching stop layer; a p-type GaAs etching stop layer and an n-type In0.5(Ga1−zAlz)0.5P current confinement layer are formed in regions other than a current injection region; and a p-type cladding layer made of AlGaAs or In0.5(Ga1−zAlz)0.5P and a p-type GaAs contact layer are formed over the entire upper surface.

Abstract: In a semiconductor laser device having a substrate and an active region, the active region includes an active layer between tensile strain optical waveguide layers. The active layer includes at least one compressive strain quantum well sublayer. When the active layer includes more than one compressive strain quantum well sublayer, the active layer further includes at least one barrier sublayer being formed between the more than one quantum well sublayer and having an identical amount of tensile strain to that of the optical waveguide layers. The absolute value of a sum of a product of the strain and the total thickness of the at least one quantum well sublayer and a product of the strain and the total thickness of the optical waveguide layers and the at least one barrier sublayer (if any) is equal to or smaller than 0.05 nm.

Abstract: In a process for producing a substrate for use in a semiconductor element: a first GaN layer having a plurality of pits at its upper surface is formed; and then a second GaN layer is formed by growing a GaN crystal over the first GaN layer until the upper surface of the second GaN layer becomes flattened. Each of the above plurality of pits has an opening area of 0.005 to 100 &mgr;m2 and a depth of 0.1 to 10.0 &mgr;m.

Abstract: In a semiconductor laser device including an active region which is made of an aluminum-free material and a plurality of cladding layers made of at least one AlGaAs or AlGaInP material, the active region includes a quantum well layer and at least one optical waveguide layer; a portion of the at least one optical waveguide layer located on one side of the quantum well layer has a thickness of 0.25 &mgr;m or more; and the at least one optical waveguide layer, other than a portion of the at least one optical waveguide layer being located near the quantum well layer and having a thickness of at least 10 nm, is doped with impurity of 1017 cm−3 or more.

Abstract: In a semiconductor laser device having an InGaAsP compressive strain quantum well active layer, an InGaAsP first upper optical waveguide layer formed on the active layer, and a current confinement layer which is formed above the first upper optical waveguide layer and includes a stripe groove. An AlGaAs second upper optical waveguide layer having an approximately identical refractive index to that of the first upper optical waveguide layer covers the current confinement layer and the stripe groove. The product of the strain and the thickness of the active layer does not exceed 0.25 nm. All the layers other than the compressive strain quantum well active layer lattice-match with GaAs. An AlGaAs or InGaAsP upper cladding layer formed above the second upper optical waveguide layer has an approximately identical refractive index to that of a lower cladding layer formed under the active layer.

Abstract: In a semiconductor-laser device: an n-type cladding layer, an optical-waveguide layer, an Inx3Ga1−x3As1−y3Py3 compressive-strain quantum-well active layer (0<x3≦0.4, 0≦y3≦0.1), an optical-waveguide layer, a p-Inx6Ga1−x6P etching-stop layer (0≦x6≦1), a p-Inx1Ga1−x1As1−y1Py1 etching-stop layer (0≦x1≦0.4, 0≦y1≦0.5), a p-InxGa1−xP layer (x=0.49±0.01), and an n-InxGa1−xP current-confinement layer are formed on an n-GaAs substrate. A stripe groove is formed down to the depth of the upper surface of the p-Inx6Ga1−x6P etching-stop layer. A p-Inx4Ga1−x4As1−y4Py4 cladding layer (x4=0.49y4±0.01, x−0.04≦x4≦x−0.01) is formed over the current-confinement layer and the stripe groove. A p-type contact layer is formed on the p-Inx4Ga1−x4As1−y4Py4 cladding layer. The absolute value of the product of the strain and the thickness of the active layer does not exceed 0.

Abstract: In a semiconductor laser element: an n-type cladding layer, an undoped or n-type optical waveguide layer, an Inx3Ga1-x3As1-y3Py3 quantum-well active layer, and an undoped or p-type optical waveguide layer are formed on an n-type GaAs substrate; a first etching stop layer and an n-type first current confinement layer are formed corresponding to high-refractive-index regions realizing an ARROW structure; a second etching stop layer and an n-type second current confinement layer are formed with an opening for current injection; and a p-type cladding layer and a p-type GaAs contact layer are formed over the entire upper surface. For example, the compositions of the cladding layers, the optical waveguide layers, the first etching stop layer, the first current confinement layer, the second etching stop layer, and the second current confinement layer are In0.49Ga0.51P (or Alz1Ga1-z1As) , GaAs, p-type Inx8Ga1-x8P, GaAs, n-type or p-type Inx8Ga1-x8P, and Alz1Ga1-z1As, respectively.

Abstract: Heating at the end face while operating in a high output is prevented and reliability improves in a semiconductor laser device. On an n-GaAs substrate, laminated are n-Alz1Ga1-z1As lower cladding layer, an n- or i-In0.49Ga0.51P lower optical waveguide layer, an Inx3Ga1-x3As1-y3Py3 quantum well active layer, a p- or i-In0.49Ga0.51P upper first optical waveguide layer, a GaAs cap layer and SiO2 film. Then a width of about 20 &mgr;m of the SiO2 film is removed inwardly from the cleaved surface. Using the SiO2 film as a mask, the cap layer near the end face and the upper first optical waveguide layer are removed. Then the SiO2 film, the quantum well active layer near the end face and the remaining cap layer are removed. A p- or i-In0.49Ga0.51P upper second optical waveguide layer, a p-Alz1Ga1-z1As upper cladding layer and a p-GaAs contact layer are deposited thereon.

Abstract: In a semiconductor laser element, a lower cladding layer of a first conductive type, a lower optical waveguide layer of the first conductive type or an undoped type, a lower GaAs layer, a compressive-strain quantum well active layer, and an upper GaAs layer are formed on a GaAs substrate of the first conductive type. The upper GaAs layer, the active layer, and the lower GaAs layer are partially removed in a vicinity of end facets of a resonator, and the space of the vicinity of end facets is filled with an upper optical waveguide layer of a second conductive type or an undoped type, an upper cladding layer of the second conductive type, and a GaAs contact layer of the second conductive type. Thus a window structure is formed in the vicinity of the end facets.

Abstract: In a semiconductor-laser device: a compressive-strain quantum-well active layer is made of Inx3Ga1−x3As1−y3Py3 (0<x3≦0.4 and 0≦y3≦0.1); tensile-strain barrier layers made of Inx2Ga1−2AS1−y2P1−y2 (0≦x2<0.49y2 and 0<y2≦0.4)are formed above and under the compressive-strain quantum-well active layer; and optical waveguide layers being made of either p-type or i-type In0.49Ga0.51P are formed above the upper tensile-strain barrier layer and under the lower tensile-strain barrier layer. Preferably, the absolute value of a sum of a first product and a second product is less than or equal to 0.25 nm, where the first product is a product of a strain and a thickness of said compressive-strain active layer, and the second product is a product of a strain of said lower and upper tensile-strain barrier layers and a total thickness of the lower and upper tensile-strain barrier layers.

Abstract: In a semiconductor laser device, a lower cladding layer, a lower optical waveguide layer, an active layer, an upper optical waveguide layer, an upper cladding layer, and a contact layer are formed in this order on a GaAs substrate. The semiconductor laser device has at least one of first and second resistance reduction layers. The first resistance reduction layer is arranged between the substrate and the lower cladding layer, and made of an InGaAsP material having an energy gap which is greater than the energy gap of the substrate, and smaller than the energy gap of the lower cladding layer. The second resistance reduction layer is arranged between the upper cladding layer and the contact layer, and made of an InGaAsP material having an energy gap which is greater than the energy gap of the contact layer, and smaller than the energy gap of the upper cladding layer.

Abstract: In a process for producing a semiconductor laser device, an n-type cladding layer, an n-type or i-type Inx2Ga1−x2As1−y2Py2 first lower optical waveguide layer, an i-type Inx5Ga1−x5P intermediate layer, an i-type Inx2Ga1−x2As1−y2Py2 second lower optical waveguide layer, an Inx1Ga1−x1As1−y1Py1 compressive strain active layer, a p-type or i-type Inx2Ga1−x2As1−y2Py2 first upper optical waveguide layer, and an Inx5Ga1−x5P cap layer are formed on an n-type GaAs substrate. Then, near-edge portions of the cap layer are etched off with a hydrochloric acid etchant, and near-edge portions of the active region above the intermediate layer are etched off with a sulfuric acid etchant so as to produce spaces in vicinities of end facets. Next, the spaces are filled with a p-type Inx2Ga1−x2As1−y2Py2 second upper optical waveguide layer formed over the cap layer, and a p-type upper cladding layer is formed on the second upper optical waveguide layer.

Abstract: In a semiconductor laser element: an n-type AlxGa1−x As cladding layer, an undoped or n-type In0.49Ga0.51P optical waveguide layer, an Inx1Ga1−x1As1−y1Py1 compressive-strain quantum-well active layer, an undoped or p-type In0.49Ga0.51P optical waveguide layer, and a p-type GaAs etching stop layer are formed on an n-type GaAs substrate; a p-type Inx8Ga1−x8P etching stop layer and an n-type GaAs current confinement layer are formed corresponding to high-refractive-index regions which realize an ARROW structure; a p-type Inx9Ga1−x9P etching stop layer is formed over the n-type GaAs current confinement layer and exposed areas of the first etching stop layer; a p-type GaAs etching stop layer and an n-type In0.5(Ga1−zAlz)0.5P current confinement layer are formed in regions other than a current injection region; and a p-type cladding layer made of AlGaAs or In0.5(Ga1−zAlz)0.5P and a p-type GaAs contact layer are formed over the entire upper surface.

Abstract: A semiconductor laser element capable of reducing an element resistance and producing a beam of high quality includes: an n-Ga1−Z4AlZ4N composition gradient layer provided between an n-GaN contact layer and an n-Ga1−Z1AlZ1N/GaN superlattice clad layer; an n-Ga1−Z5AlZ5N composition gradient layer provided between the n-Ga1−Z1AlZ1N/GaN superlattice clad layer and an n- or i-Ga1−Z2AlZ2N optical waveguide layer; a p-Ga1−Z5AlZ5N composition gradient layer provided between a p- or i-Ga1−Z2AlZ2N optical waveguide layer and a p-Ga1−Z1AlZ1N superlattice gradient layer; and a p-Ga1−Z4AlZ4N composition gradient layer provided between a p-Ga1−Z1AlZ1N/GaN superlattice upper clad layer and a p-GaN contact layer. Z4 of the n-Ga1−Z4AlZ4N composition gradient layer is continuously changed from 0 to a composition corresponding to the band gap of the Ga1−Z1AlZ1N/GaN superlattice clad layer.

Abstract: In a process for producing a substrate for use in a semiconductor element: a growth suppression mask which is constituted by a plurality of mask elements being discretely arranged and each having a width of 2.5 micrometers or smaller is formed on a surface of a base substrate; a first GaN layer having a plurality of holes is formed on the surface of the base substrate by growing GaN from areas of the surface of the base substrate which are not covered by the plurality of first mask elements; and a second GaN layer is formed over the first GaN layer by crystal growth.

Abstract: In a semiconductor laser element, a lower cladding layer of a first conductive type, a GaAs first optical waveguide layer of the first conductive type or an undoped type, an InGaAsP or InGaAs compressive-strain active layer, a GaAs second optical waveguide layer of a second conductive type or an undoped type, and an upper cladding portion are formed on a GaAs substrate of the first conductive type. The active layer is not formed in at least one vicinity of at least one end facet, and the space in the at least one vicinity of the at least one end facet is filled with a third optical waveguide layer of the second conductive type or an undoped type, where the bandgaps of the first, second, and third second optical waveguide layers are greater than the bandgap of the active layer.

Abstract: An n-GaAs buffer layer, an n-Alz1Ga1-z1As cladding layer, an n- or i-In0.49Ga0.51P waveguide layer, an i-Inx3Ga1-x3As1-y3Py3 barrier layer, a compressive strain Inx1Ga1-x3As1-y3Py3 quantum well active layer, an i-Inx3Ga1-x3As1-y3Py3 upper barrier layer, and an In0.49Ga0.51P cap layer are laminated on an n-GaAs substrate. Regions near facets of the barrier layer to the cap layer are removed, and a p- or i-type In0.49Ga0.51P upper optical waveguide layer is laminated on the cap layer to fill in the removed portions. A p-GaAs etching stop layer, an n-In0.49(Alz2Ga1-z2)0.51P current confinement layer having an opening, an n-In0.49Ga0.51P second cap layer, a p-In0.49Ga0.51P second upper optical waveguide layer 34 and a p-Alz1Ga1-z1As upper cladding layer are laminated thereon, and a p-GaAs contact layer is formed inwardly except near the facets on the laminated surface, and an insulation film is formed on the regions near the facets, and a p-side electrode is provided as an uppermost layer.