Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Yoshihiko Hanamaki

Kenichi Ono

Tohru Takiguchi

Makoto Takada

Kimio Shigihara

Kazushige Kawasaki

Toshio Tanaka

Yutaka Mihashi

Masayoshi Takemi

Kimitaka Shibata

Nobuyuki Tomita

Chikara Watatani

Takehiro Nishida

Tomoko Kadowaki

Naoyuki Shimada

A method for manufacturing a semiconductor optical device includes forming a BDR (Band Discontinuity Reduction) layer of a first conductivity type doped with an impurity, depositing a contact layer of the first conductivity type in contact with the BDR layer after forming the the BDR layer, the contact layer being doped with the same impurity as the BDR layer and used to form an electrode, and heat treating after forming the contact layer.

Method for manufacturing semiconductor optical device

A method for manufacturing a semiconductor optical device includes: forming a p-type cladding layer; forming a capping layer on the p-type cladding layer, the capping layer being selectively etchable relative to the p-type cladding layer; forming a through film on the capping layer; forming a window structure by ion implantation; removing the through film after the ion implantation; and selectively removing the capping layer using a chemical solution.

A laser diode includes a first n-cladding layer disposed on and lattice-matched to an n-semiconductor substrate, wherein the first n-cladding layer is n-AlGaInP or n-GaInP; a second n-cladding layer of n-AlGaAs supported by the first n-cladding layer; and an inserted layer disposed between the first n-cladding layer and the second n-cladding layer, wherein the inserted layer includes the same elements as the first n-cladding layer, the inserted layer has the same composition ratios of Al and Ga (and P) as the first n-cladding layer, and the inserted layer contains a lower composition ratio of In than the first n-cladding layer.

Semiconductor device and manufacturing method therefor

In a semiconductor laser, a n-type AlGaInP clad layer is formed on a n-type GaAs substrate and an active layer having an emission wavelength of 600 to 850 nm is formed on the n-type AlGaInP clad layer. A p-type AlGaInP clad layer is formed on the active layer and a p-type AlGaAs contact layer in which the Al composition is controlled so that the p-type AlGaAs contact layer has an optical bandgap larger than that of the active layer is formed on the p-type AlGaInP clad layer. A p-type GaAs cap layer is formed on the p-type AlGaAs contact layer.

Semiconductor laser

An n-type first cladding layer, a first guide layer, a first enhancing layer, an active layer, a second enhancing layer, a second guide layer, and a p-type second cladding layer are sequentially stacked on an n-type GaAs substrate. The thickness of each of the first guide layer and the second guide layer is 100 nm or more. In such a semiconductor laser, the difference between the Eg (band gap energy) of the first guide layer and the Eg of the active layer (or the difference between the Eg of the second guide layer and the Eg of the active layer) is made 0.66 times or less of the difference between the Eg of the first cladding layer and the Eg of the active layer (or the difference between the Eg of the second cladding layer and the Eg of the active layer).

Semiconductor laser having an improved stacked structure

A semiconductor optical element having a includes an n-type GaAs buffer layer, an n-type AlGaInP cladding layer, a first InGaAsP (including zero As content)guide layer without added dopant impurities, an InGaAsP (including zero In content) active layer, a second InGaAsP (including zero As content)guide layer without added dopant impurities, a p-type AlGaInP cladding layer, a p-type band discontinuity reduction layer, and a p-type GaAs contact layer sequentially laminated on an n-type GaAs substrate C or Mg is the dopant impurity in the p-type GaAs contact layer, the p-type band discontinuity reduction layer, and the p-type AlGaInP cladding layer.

Semiconductor optical element

A ridge waveguide semiconductor laser includes an active layer, semiconductor layers on the active layer and having a ridge-shaped waveguide, an insulating film on the semiconductor layer, a first electrode layer in contact with the semiconductor layer through an opening in the insulating film, and a second electrode layer on the first electrode layer having a stripe shape and extending along the waveguide. A distance from an end face of a resonator of the laser to an edge of the second electrode layer does not exceed 20 &#x3bc;m.

Ridge waveguide semiconductor laser

In an optical semiconductor device including, at least, an n-type semiconductor layer having n-type conductivity, an active layer, a p-type semiconductor layer having p-type conductivity, current blocking layers doped with Fe are located on opposite sides of the p-type semiconductor layer. Fe and Be are simultaneously supplied as dopants when forming the p-type semiconductor layer. In this event, the flow rates of source materials supplying the respective elements are adjusted so that the p-type semiconductor layer has a hole concentration of about 1.0&#xd7;10/cmand an Fe concentration of about 2&#xd7;10to 8&#xd7;10/cm.

Optical semiconductor device and method of fabricating optical semiconductor device

In a semiconductor light-emitting device, an active layer has a multi quantum well structure (MQW) barrier layers and quantum well layers alternately arranged. Each of the cladding layers has a multi quantum barrier structure (MQB) including barrier layers and well layers alternately arranged. The multi quantum barrier (MQB) of each of the cladding layers varies in a graded or stepwise form. Thus, charge carriers are prevented from overflowing from the active layer, preventing cut-off of a guided wave mode, increasing reflectance of electrons entering the energy barriers, and improving temperature characteristics.

Semiconductor light-emitting device using graded multi quantum barrier

A semiconductor optical device with improved optical gain and enhanced switching characteristics. The semiconductor optical device includes positive and negative electrodes for providing holes and electrons, respectively. The semiconductor optical device also includes an active layer between the positive and negative electrodes. The active layer includes a multiple quantum well structure having p-type quantum well layers and barrier layers. The quantum well layers are doped with an impurity that diffuses less than zinc so that trapping holes are produced and excessive electrons contributing no light emission are quenched by the trapping holes. The impurity can be beryllium, magnesium, or carbon.

Optical semiconductor device

A laser device includes a double hetero-structure element constructed by depositing a p-type cladding layer, a quantum well active layer, an n-type thin first cladding layer and an n-type thick second cladding layer sequentially. A ridge-waveguide is shaped between two trenches formed in the second cladding layer. The first cladding layer serves as an etching stopper while etching the second cladding layer to form the two trenches. The trenches reach to or reach in vicinity to the surface of the first cladding layer. High-resistance regions may be formed in portions of the first cladding layer directly underneath the trenches. The thin first cladding layer, suppresses leakage current and improves the temperature characteristics and the operating speed characteristics of the laser device.

Ridge-waveguide semiconductor laser device

A distributed feedback laser device includes a semiconductor base having a ridge waveguide structure projecting from its principal plane. The ridge waveguide structure extends with a predetermined width from one edge of the semiconductor base to an opposite edge. A diffraction grating layer is confined within the ridge structure. The ridge waveguide structure is formed by etching using an SiO film and a resist film as masks so that the diffraction grating layer is produced with substantially the same width as, or a less width than, the width of the ridge waveguide structure. A &lgr;/4 shift diffraction grating or a chirped diffraction grating is preferably employed.

Distributed feedback laser device and method for manufacturing the same

An electrode for a semiconductor device includes a gold-containing thin film and a gold-containing plated film on the thin film. The plated film covers the entire thin film. No open surface is present between the thin gold film and the gold plating so no excessive current concentration occurs in any area.

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Tokyo, Japan

Yoshihiko Hanamaki