Fujitsu Corporation

Akito Kuramata

Shinichi Kubota

Kazuhiko Horino

Nami Yasuoka

Haruhiko Kuwatsuka

Reiko Soejima

Chikashi Anayama

Haruhisa Soda

Toru Uchida

Susumu Yamazaki

Kay Domen

Hirohide Kurakake

A semiconductor photodetecting device including a PIN photodiode formed on an SI-InP substrate; a buried optical waveguide portion formed on the SI-InP substrate and including the film thickness continuously increased toward the PIN photodiode and an InP clad layer covering the upper surface and the side surface of the InGaAsP core layer; and a ridge-shaped connection optical waveguide portion formed on the SI-InP substrate between the PIN photodiode and the buried optical waveguide portion and including the InGaAsP core layer and the InP clad layer selectively covering only the upper surface of the InGaAsP core layer.

Semiconductor photodetecting device and method for fabricating the same

An optical circuit device including a substrate of a III&#x2013;V group compound semiconductor, and a magnetic semiconductor layer having a chalcopyrite type crystal structure. The magnetic semiconductor having the chalcopyrite type crystal structure is a material which can provide Faraday effect, and the use of such material makes it possible to form the Faraday rotation element. Furthermore, the magnetic semiconductor having the chalcopyrite type crystal structure which can lattice-match with the substrates have little crystal defects, which can make a light loss of the Faraday rotation element small. The magnetic semiconductor of the chalcopyrite type crystal structure can provide large Verdet's constant, which makes it possible to reduce a length of the Faraday rotation element and resultantly makes it possible to micronize the optical circuit device.

Optical circuit device and method for fabricating the same

An optical semiconductor device includes an SiC substrate having an n-type conductivity, and an AlGaN buffer layer having an n-type conductivity formed on the SiC substrate with a composition represented as AlGaN, wherein the AlGaN buffer layer has a carrier density in the range between 3&#xd7;10&#x2013;1&#xd7;10cm, and the compositional parameter x is larger than 0 but smaller than 0.4 (0&#x3c;x&#x3c;0.4).

Optical semiconductor device having an epitaxial layer of III-V compound semiconductor material containing N as a group V element

A lateral mode controlling layer made of AlN having a thickness of more than 0 nm but less than 300 nm is formed in at least one cladding layer of an n-type cladding layer and a p-type cladding layer or formed between the at least one cladding layer and the active layer. Also, a mask layer is formed on a substrate, then an AlN layer is formed to cover it, and then the AlN layer is lifted off by using a solution for etching. the mask layer. Accordingly, lateral mode control of the group III-V compound semiconductor laser can be facilitated, the aspect ratio of the beam shape can be improved, and the damage caused by the Al layer growth and the patterning can be reduced.

Semiconductor light emitting device and method of manufacturing the same

A substrate is made of SiC. A plurality of Al Ga N patterns (0&lE;x&lE;1) is formed on a surface of the substrate and dispersively distributed in an in-plane of the substrate. An Al Ga N buffer layer (0&lE;y&lE;1) covers the surface of the substrate and the Al Ga N patterns. A laser structure is formed on the Al Ga N 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.

Semiconductor laser, semiconductor device, and their manufacture methods

There are provided a semiconductor laser, a semiconductor light emitting device, and methods of manufacturing the same wherein a threshold current density in a short wavelength semiconductor laser using a nitride compound semiconductor can be reduced. An active layer is composed of a single gain layer having a thickness of more than 3 nm, and optical guiding layers are provided between the active layer and cladding layers respectively.

Semiconductor laser, semiconductor light emitting device, and methods of manufacturing the same

The present invention relates to a semiconductor laser having light emitting wavelengths from blue to UV, more specifically a semiconductor laser which can form a laser resonator by perpendicular cleavage of the substrate and a method for fabricating the semiconductor laser. The semiconductor laser comprises a single crystal substrate 10 of cubic system, and an epitaxial crystal layer 12 with the laser resonator formed by cleavage planes 30 thereof. Cleavage planes 28 of the single crystal substrate 10 and the cleavage planes 30 of the epitaxial crystal layer 12 are not parallel with each other, and the intersection between the cleavage planes 30 of the epitaxial crystal layer 12 and the surface of the single crystal substrate substantially agrees with the intersection L between the cleavage planes 28 of the single crystal substrate 10 and the surface of the single crystal substrate 10.

Semiconductor laser and method for fabricating the same

A group III-V compound semiconductor laser of a 1 .mu.m band having an excellent conversion efficiency and a high characteristic temperature. The semiconductor laser can emit light in a 1.3 .mu.m band or a 1.55 .mu.m, and has a laser structure including an active layer For emitting light, guide layers sandwiching the active layer and having a band gap larger than the active layer, and clad layers embracing the guide layers and having a band gap larger than the guide layers. The lattice constants of the guide layers and clad layers are larger than a1 by 0.5% or more and smaller than a2 by 0.5% or more, where a1 represents the lattice constant of GaAs and a2 is the lattice constant of InP.

Semiconductor laser

A process for growing a semiconductor crystal, comprising growing a group III-V compound semiconductor containing P as a group V element by an organometal vapor phase epitaxy by using tertiary butyl phosphine (TBP) as a source of P constituting a grown layer and doping the semiconductor with a dopant gas during a growth of the semiconductor. In this process, the source gas and dopant gas are fed under a condition satisfying a requirement represented by the following formula, to conduct a growth of the crystal: ##EQU1## wherein n is a carrier concentration of the growing semiconductor crystal, T is a temperature of the substrate and an atmosphere in the vicinity of the substrate, P.sub.TBP.sup.0 is an equilibrium vapor pressure of TBP or a decomposition product thereof, P.sub.D.sup.0 is an equilibrium vapor pressure of a dopant or a decomposition product thereof, P.sub.0 is a total pressure, f.sub.0 is a total flow rate, and f.sub.TBP is a flow rate of TBP.

Growing community of inventors

Kawasaki, Japan

Akito Kuramata