2027results about "Semiconductor laser structural details" patented technology

PCT No. PCT/JP98/01640 Sec. 371 Date Dec. 9, 1998 Sec. 102(e) Date Dec. 9, 1998 PCT Filed Apr. 9, 1998 PCT Pub. No. WO98/47170 PCT Pub. Date Oct. 22, 1998A method of growing a nitride semiconductor crystal which has very few crystal defects and can be used as a substrate is disclosed. This invention includes the step of forming a first selective growth mask on a support member including a dissimilar substrate having a major surface and made of a material different from a nitride semiconductor, the first selective growth mask having a plurality of first windows for selectively exposing the upper surface of the support member, and the step of growing nitride semiconductor portions from the upper surface, of the support member, which is exposed from the windows, by using a gaseous Group 3 element source and a gaseous nitrogen source, until the nitride semiconductor portions grown in the adjacent windows combine with each other on the upper surface of the selective growth mask.

A multi-wavelength laser device includes at least two of a blue laser diode, a red laser diode, and an infrared laser diode, which are arranged in the same direction on the same base. One laser light emission point is arranged behind another in increasing order of wavelengths of the laser diodes.

A semiconductor laser device have, on a substrate, a semiconductor layer including an active layer sandwiched between an n-type layer and a p-type layer, the semiconductor layer having a sonator face formed by etching and a projection projecting out in an emission direction relatively to the resonator face, wherein a protective film is formed to extend from the resonator face to an end face of the projection, and, an emission critical angle, which is the largest angle at which light emitted from the resonator face can be radiated without being blocked by the projection and the protective film formed on the projection, is larger than an emission half-angle of an emission distribution in a vertical direction of a laser beam emitted from the resonator face.

It has a structure in which an active layer (5) that emits light by electric current injection is sandwiched between an n-type cladding layer (4) and a p-type cladding layer (6) made of materials having a larger band gap than the active layer (5), wherein the active layer (5) is made, for example, of Cd_xZn_1−xO (0≦x<1). It is further more preferable if the cladding layers (4), (6) are made, for example, of Mg_yZn_1−yO (0≦y<1). This narrows the band gap of the ZnO materials, and an oxide semiconductor capable of being wet-etched, easy to handle with, and excellent in crystallinity can be used as a material for an active layer or a cladding layer of a semiconductor light emitting device such as a blue light emitting diode or a blue laser diode in which an active layer is sandwiched between cladding layers, so that a blue semiconductor light emitting device being excellent in light emission characteristics can be obtained.

A method of fabricating a gallium nitride-based semiconductor structure on a substrate includes the steps of forming a mask having at least one opening therein directly on the substrate, growing a buffer layer through the opening, and growing a layer of gallium nitride upwardly from the buffer layer and laterally across the mask. During growth of the gallium nitride from the mask, the vertical and horizontal growth rates of the gallium nitride layer are maintained at rates sufficient to prevent polycrystalline material nucleating on said mask from interrupting the lateral growth of the gallium nitride layer. In an alternative embodiment, the method includes forming at least one raised portion defining adjacent trenches in the substrate and forming a mask on the substrate, the mask having at least one opening over the upper surface of the raised portion. A buffer layer may be grown from the upper surface of the raised portion. The gallium nitride layer is then grown laterally by pendeoepitaxy over the trenches.

External Cavity Laser An external cavity laser comprising first and second feedback means with an optical gain medium (2) therebetween, one of the feedback means is provided by a grating (4) formed in a silicon waveguide and the other feedback means is provided by a reflective back facet (2B) of the optical gain medium (2). The output wavelength of the laser, at a given temperature, can thus be determined during its manufacture and the laser can be made by mass production techniques. The grating (4) may be thermally isolated to obviate the need for temperature control means (6) to control the temperature of the grating (4). An array of lasers may be provided on a single chip.

A tunable optical source comprises a laser diode and an external optical feedback device. The feedback device has a waveguiding portion fabricated at least in part out of a glass material having both organic and inorganic components. A control device is provided for controlling the refractive index of the glass material so as to change the wavelength of feedback to the laser diode. The glass material may for example have thermo-optic properties and the control device might then be a heating device for heating the glass material. The feedback device can have more than one portion, a second portion for example having controllable coupling characteristics for coupling optical radiation into or out of the feedback device. It also preferably has a portion for controlling optical path length in the feedback device.

Disclosed herein is a method for producing a multi-wavelength semiconductor laser device. The method comprises the steps of: forming first and second nitride epitaxial layers in parallel on a substrate for growth of a nitride single crystal; separating the first and second nitride epitaxial layers from the substrate; attaching the separated first and second nitride epitaxial layers to a first conductivity-type substrate; selectively removing the first and second nitride semiconductor epitaxial layers to expose a portion of the first conductivity-type substrate and to form first and second semiconductor laser structures, respectively; and forming a third semiconductor laser structure on the exposed portion of the first conductivity-type substrate.

Starting point regions for cutting 8a, 8b extending along lines to cut 5a, 5b are initially formed in an object to be processed 1. The starting point regions for cutting 8b have modified regions 7b formed by irradiating the object 1 with laser light while locating a converging point within the object 1 and are formed in parts extending along the lines to cut 5b excluding portions 34b intersecting the lines to cut 5a. This makes the starting point regions for cutting 8b much less influential when cutting the object 1 from the starting point regions for cutting 8a acting as a start point, whereby bars with precise cleavage surfaces can reliably be obtained. Therefore, it is unnecessary to form a starting point region for cutting along the lines to cut 5b in each of a plurality of bars, whereby the productivity of semiconductor laser elements can be improved.

A substrate is made of SiC. A plurality of AlxGa1-xN patterns (0<=x<=1) is formed on a surface of the substrate and dispersively distributed in an in-plane of the substrate. An AlyGa1-yN buffer layer (0<=y<=1) covers the surface of the substrate and the AlxGa1-xN patterns. A laser structure is formed on the AlyGa1-yN buffer layer. Since the AlGaN buffer layer is grown by using the AlGaN patterns as seed crystals, a dislocation density of a predetermined region in the AlGaN buffer layer can be lowered. The characteristics of a laser structure can be improved by forming the laser structure above the region having a low dislocation density. Since the AlGaN pattern has electric conductivity, the device resistance can be suppressed from being increased.

The method of making a GaN single crystal substrate comprises a mask layer forming step of forming on a GaAs substrate 2 a mask layer 8 having a plurality of opening windows 10 disposed separate from each other; and an epitaxial layer growing step of growing on the mask layer 8 an epitaxial layer 12 made of GaN.

A hybrid laser for generating radiation includes an optical passive material and an optical active material. The laser includes a first optical waveguide and optical laser components with reflectors in the optical passive material. The first optical waveguide is adapted for coupling out radiation from the hybrid laser. The laser also includes a second optical waveguide defined in the optical active material. The optical laser components include reflectors defining a cavity and furthermore are adapted for providing laser cavity confinement in the first optical waveguide and the second optical waveguide. The second optical waveguide thereby is positioned at least partly over the first optical waveguide so that an evanescent coupling interface is defined between the second optical waveguide and the first optical waveguide and the evanescent coupling interface is positioned within the laser cavity.

A semiconductor device includes at least one defect-free epitaxial layer. At least a part of the device is manufactured by a method of fabrication of defect-free epitaxial layers on top of a surface of a first solid state material having a first thermal evaporation rate and a plurality of defects, where the surface comprises at least one defect-free surface region, and at least one surface region in a vicinity of the defects, the method including the steps of selective deposition of a second material, having a high temperature stability, on defect-free regions of the first solid state material, followed by subsequent evaporation of the regions in the vicinity of the defects, and subsequent overgrowth by a third material forming a defect-free layer.

A nitride semiconductor laser device with a reduction in internal crystal defects and an alleviation in stress, and a semiconductor optical apparatus comprising this nitride semiconductor laser device. First, a growth suppressing film against GaN crystal growth is formed on the surface of an n-type GaN substrate equipped with alternate stripes of dislocation concentrated regions showing a high density of crystal defects and low-dislocation regions so as to coat the dislocation concentrate regions. Next, the n-type GaN substrate coated with the growth suppressing film is overlaid with a nitride semiconductor layer by the epitaxial growth of GaN crystals. Further, the growth suppressing film is removed to adjust the lateral distance between a laser waveguide region and the closest dislocation concentrated region to 40 μm or more.

There is provided a group III nitride semiconductor epitaxial substrate which has a suppressed level of threading dislocation in the vertical direction and excellent crystal quality, the group III nitride semiconductor epitaxial substrate including a substrate (1) for growing an epitaxial film; and an ELO layer (4) having a composition of Al_xGa_1-xN (0≦x≦1) formed either on top of the substrate (1) or on top of a group III nitride layer (2) formed on top of the substrate (1), wherein the ELO layer (4) is a layer formed by using a mask pattern (3), which is composed of carbon and is formed either on top of the substrate (1) or on top of the group III nitride layer (2).

An opposed terminal structure including a supporting substrate, a first terminal, a nitride semiconductor with a light-emitting layer, and a second terminal. The second terminal forms an opposed terminal structure with the first terminal, which can be formed in a variety of patterns.

An electro-optical transceiver system with controlled lateral light leakage and a method of making such a system includes a plurality of emitter devices and detector devices including at least one of each, arranged in a planar array for transmitting and receiving, respectively, energy in a predetermined wavelength and a blocking medium disposed interstitially of the devices and being absorbing at the predetermined wavelength for blocking energy at the predetermined wavelength laterally leaking from an emitter device to one or more detector devices.