Abstract: A depletion enhancement layer having a striped opening on the upper surface of a ridge portion, a low carrier concentration layer and an n-type current blocking layer are successively formed on a p-type cladding layer having the ridge portion. The low carrier concentration layer has a lower carrier concentration than the n-type current blocking layer. The band gap of the depletion enhancement layer is set to an intermediate level between the band gaps of the p-type cladding layer and the low carrier concentration layer. Alternatively, a first current blocking layer having a low carrier concentration and a second current blocking layer of the opposite conduction type are formed on an n-type depletion enhancement layer, and a p-type contact layer is formed on the second current blocking layer of the opposite conduction type and another p-type contact layer.

Abstract: A highly reliable semiconductor laser device having a low operating voltage is obtained by increasing adhesive force of the overall electrode layer to a nitride-based semiconductor layer without deteriorating a low contact property. This nitride-based semiconductor laser device comprises a nitride-based semiconductor layer formed on an active layer and an electrode layer formed on the nitride-based semiconductor layer, while the electrode layer includes a first electrode layer containing a material having strong adhesive force to the nitride-based semiconductor layer and a second electrode layer, formed on the first electrode layer, having weaker adhesive force to the nitride-based semiconductor layer than the first electrode layer for reducing contact resistance of the electrode layer with respect to the nitride-based semiconductor layer.

Abstract: A nitride-based semiconductor light-emitting device having low operating voltage with high reliability is obtained by improving adhesion of the whole of an electrode layer to a nitride-based semiconductor layer without damaging a low contact property. This nitride-based semiconductor light-emitting device comprises the nitride-based semiconductor layer formed on an active layer and the electrode layer partially formed on the nitride-based semiconductor layer. The electrode layer includes a first electrode layer containing a material having strong adhesion to the nitride-based semiconductor layer and a second electrode layer formed on the first electrode layer to have a portion coming into contact with the surface of the nitride-based semiconductor layer with weaker adhesion to the nitride-based semiconductor layer than the first electrode layer for reducing contact resistance of the electrode layer to the nitride-based semiconductor layer.

Abstract: A nitride-based semiconductor element capable of effectively preventing a nitride-based semiconductor layer of a first area from cracking and reducing the degree of warpage of a substrate is obtained. This nitride-based semiconductor element comprises a first region formed on a prescribed region of a substrate and provided with an element including a first nitride-based semiconductor layer having a prescribed thickness and a second region formed on a region of the substrate other than the first region and provided with the first nitride-based semiconductor layer with a thickness smaller than the thickness in the first region. Thus, strain easily concentrates to the second region provided with the first nitride-based semiconductor layer with the smaller thickness, whereby strain of the first region provided with the element is relaxed.

Abstract: A thin nitride-based semiconductor layer having a low dislocation density is formed by laterally growing a nitride-based semiconductor layer on the upper surface of an underlayer and forming quantum dots on the laterally grown nitride-based semiconductor layer. The number of dislocations is reduced by a single lateral growth and is further reduced due to a dislocation loop effect by the quantum dots, without repeating lateral growth.

Abstract: A nitride-based semiconductor light-emitting device capable of improving luminous efficiency by reducing light absorption loss in a contact layer is provided. This nitride-based semiconductor light-emitting device comprises a first conductivity type first nitride-based semiconductor layer formed on a substrate, an active layer, formed on the first nitride-based semiconductor layer, consisting of a nitride-based semiconductor layer, a second conductivity type second nitride-based semiconductor layer formed on the active layer, an undoped contact layer formed on the second nitride-based semiconductor layer and an electrode formed on the undoped contact layer.

Abstract: A nitride-based semiconductor laser device capable of attaining stabilization of a laser beam and inhibiting a threshold current and an operating current from increase is provided. This nitride-based semiconductor laser device comprises a substrate consisting of either a nitride-based semiconductor doped with an impurity or a boride-based material, an n-type cladding layer formed on the substrate, an active layer consisting of a nitride-based semiconductor formed on the n-type cladding layer, a p-type cladding layer formed on the active layer and a light guide layer formed only between the active layer and the p-type cladding layer in the interspaces between the active layer and the n- and p-type cladding layers.

Abstract: A method of fabricating a nitride-based semiconductor device capable of reducing contact resistance between a nitrogen face of a nitride-based semiconductor substrate or the like and an electrode is provided. This method of fabricating a nitride-based semiconductor device comprises steps of etching the back surface of a first semiconductor layer consisting of either an n-type nitride-based semiconductor layer or a nitride-based semiconductor substrate having a wurtzite structure and thereafter forming an n-side electrode on the etched back surface of the first semiconductor layer.

Abstract: An n-GaAs current blocking layer is formed on a p-AlGaInP first cladding layer, on sides of a ridge portion and in a region on the upper surface of the ridge portion above a window region. Raised portions are formed in a p-GaAs cap layer in regions in the vicinity of facets, while raised regions are formed in the regions of a first electrode in the vicinity of the facets. A second electrode having a thickness larger than the height of the raised regions is formed on the region between the raised regions of the first electrode.

Abstract: A nitride-based semiconductor light-emitting device capable of attaining homogeneous emission with a low driving voltage is obtained. This nitride-based semiconductor light-emitting device comprises a first conductivity type first nitride-based semiconductor layer formed on a substrate, an emission layer, consisting of a nitride-based semiconductor, formed on the first nitride-based semiconductor layer, a second conductivity type second nitride-based semiconductor layer formed on the emission layer, a second conductivity type intermediate layer, consisting of a nitride-based semiconductor, formed on the second nitride-based semiconductor layer, a second conductivity type contact layer, including a nitride-based semiconductor layer having a smaller band gap than gallium nitride, formed on the intermediate layer, and a light-transmitting electrode formed on the contact layer.

Abstract: A surface emission semiconductor laser device capable of substantially completely controlling the plane of polarization is obtained. This surface emission semiconductor laser device comprises a first multi-layer reflector, an emission layer formed on the first multi-layer reflector and a second multi-layer reflector formed on the emission layer, and at least either the first multi-layer reflector or the second multi-layer reflector includes a striped part worked in a striped manner in a prescribed period.

Abstract: A nitride-based semiconductor laser device capable of elongating the life thereof is obtained. This nitride-based semiconductor laser device comprises a first cladding layer consisting of a first conductivity type nitride-based semiconductor, an emission layer, formed on the first cladding layer, consisting of a nitride-based semiconductor and a second cladding layer, formed on the emission layer, consisting of a second conductivity type nitride-based semiconductor, while the emission layer includes an active layer emitting light, a light guiding layer for confining light and a carrier blocking layer, arranged between the active layer and the light guiding layer, having a larger band gap than the light guiding layer.

Abstract: A nitride-based semiconductor light-emitting device having low operating voltage with high reliability is obtained by improving adhesion of the whole of an electrode layer to a nitride-based semiconductor layer without damaging a low contact property. This nitride-based semiconductor light-emitting device comprises the nitride-based semiconductor layer formed on an active layer and the electrode layer partially formed on the nitride-based semiconductor layer. The electrode layer includes a first electrode layer containing a material having strong adhesion to the nitride-based semiconductor layer and a second electrode layer formed on the first electrode layer to have a portion coming into contact with the surface of the nitride-based semiconductor layer with weaker adhesion to the nitride-based semiconductor layer than the first electrode layer for reducing contact resistance of the electrode layer to the nitride-based semiconductor layer.

Abstract: A semiconductor laser device capable of improving reliability is obtained in a structure formed by mounting a semiconductor laser element on a submount (base) in a junction-down system. This semiconductor laser device comprises a first electrode layer formed on the surface of a semiconductor element including an emission layer to have a shape comprising recess portions and projection portions, a base mounted with the semiconductor element, and a plurality of low melting point metal layers provided between the first electrode layer formed on the surface of the semiconductor element and the base for bonding the first electrode layer formed on the surface of the semiconductor element and the base to each other. Thus, the plurality of low melting point metal layers easily embed clearances resulting from the shape comprising recess portions and projection portions of the surface of the semiconductor element dissimilarly to a case of employing a single low melting point metal layer.

Abstract: A nitride-based semiconductor element capable of effectively preventing a nitride-based semiconductor layer of a first area from cracking and reducing the degree of warpage of a substrate is obtained. This nitride-based semiconductor element comprises a first region formed on a prescribed region of a substrate and provided with an element including a first nitride-based semiconductor layer having a prescribed thickness and a second region formed on a region of the substrate other than the first region and provided with the first nitride-based semiconductor layer with a thickness smaller than the thickness in the first region. Thus, strain easily concentrates to the second region provided with the first nitride-based semiconductor layer with the smaller thickness, whereby strain of the first region provided with the element is relaxed.

Abstract: A nitride-based semiconductor light-emitting device capable of stabilizing transverse light confinement is obtained. This nitride-based semiconductor light-emitting device comprises an emission layer, a cladding layer, formed on the emission layer, including a first nitride-based semiconductor layer and having a current path portion and a current blocking layer, formed to cover the side surfaces of the current path portion, including a second nitride-based semiconductor layer, while the current blocking layer is formed in the vicinity of the current path portion and a region having no current blocking layer is included in a region not in the vicinity of the current path portion. Thus, the width of the current blocking layer is reduced, whereby strain applied to the current blocking layer is relaxed. Consequently, the thickness of the current blocking layer can be increased, thereby stabilizing transverse light confinement.

Abstract: A nitride-based semiconductor light-emitting device capable of attaining homogeneous emission with a low driving voltage is obtained. This nitride-based semiconductor light-emitting device comprises a first conductivity type first nitride-based semiconductor layer formed on a substrate, an emission layer, consisting of a nitride-based semiconductor, formed on the first nitride-based semiconductor layer, a second conductivity type second nitride-based semiconductor layer formed on the emission layer, a second conductivity type intermediate layer, consisting of a nitride-based semiconductor, formed on the second nitride-based semiconductor layer, a second conductivity type contact layer, including a nitride-based semiconductor layer having a smaller band gap than gallium nitride, formed on the intermediate layer, and a light-transmitting electrode formed on the contact layer.

Abstract: A semiconductor laser device having a real refractive index guided structure capable of obtaining a high kink light output and a high maximum light output also when a vertical beam divergence angle is at a small level of at least 12.5° and not more than 20.0° is provided. This semiconductor laser device comprises an n-type cladding layer of AlGaInP formed on an n-type GaAs substrate, an active layer having an AlGaInP layer formed on the n-type cladding layer, a p-type cladding layer of AlGaInP formed on the active layer and a light confinement layer formed to partially cover the p-type cladding layer, and a vertical beam divergence angle is at least 12.5° and not more than 20.0°. Thus, a higher kink light output and a higher maximum light output can be obtained as compared with a conventional semiconductor laser device having a vertical beam divergence angle exceeding 20.0°.

Abstract: A method of forming a nitride-based semiconductor capable of forming a nitride-based semiconductor layer having low dislocation density with a small thickness is obtained. This method of forming a nitride-based semiconductor comprises steps of laterally growing a nitride-based semiconductor layer on the upper surface of an underlayer and forming quantum dots on the laterally grown nitride-based semiconductor layer. Thus, the number of dislocations reduced by lateral growth is further reduced due to a dislocation loop effect by the quantum dots. Therefore, a nitride-based semiconductor having lower dislocation density is formed as compared with a case of reducing the number of dislocations only by lateral growth.

Abstract: A highly reliable semiconductor laser device having a low operating voltage is obtained by increasing adhesive force of the overall electrode layer to a nitride-based semiconductor layer without deteriorating a low contact property. This nitride-based semiconductor laser device comprises a nitride-based semiconductor layer formed on an active layer and an electrode layer formed on the nitride-based semiconductor layer, while the electrode layer includes a first electrode layer containing a material having strong adhesive force to the nitride-based semiconductor layer and a second electrode layer, formed on the first electrode layer, having weaker adhesive force to the nitride-based semiconductor layer than the first electrode layer for reducing contact resistance of the electrode layer with respect to the nitride-based semiconductor layer.