Hitachi, Ltd.

Masahiko Kondow

Takashi Kajimura

Shigekazu Minagawa

Toshiaki Tanaka

Kazuhisa Uomi

Shin Satoh

Takeshi Kitatani

Shinji Nishimura

Hitoshi Nakamura

Kazunori Shinoda

Kenji Uchida

Toshihiro Kawano

Makoto Kudo

Akio Ohishi

In a semiconductor laser for emitting light perpendicular to substrate crystal, including, on the substrate crystal, an active layer for generating light, a cavity structure sandwiching the active layer by reflecting mirrors so as to obtain a laser beam from the light generated from the active layer, and a regrown semiconductor layer between the active layer and one of the reflecting mirrors, a regrown interface or a face very close to the regrown interface is formed by a thin film containing dopants of high concentration. With the configuration, an adverse influence of a contamination deposit on the regrown interface is eliminated by delta-doping the regrown interface. The cost is reduced and device resistance is also reduced to 50 &OHgr; or less. Thus, an edge emitting laser (VCSEL) for realizing a optical module achieving a high speed characteristic over 10 Gb/s is obtained.

Semiconductor laser, ray module using the same and ray communication system

A surface emitting laser device comprising, on a semiconductor substrate, an active region for generating light, a current confinement region disposed on the side opposite to the semiconductor substrate relative to the active region, an optical cavity comprising reflectors putting the active region and the current confinement region vertically therebetween in the direction of layering the semiconductor layer, a first electrode disposed on the side of the semiconductor substrate relative to the current confinement region and a second electrode disposed on the side opposite to the semiconductor layer relative to the current confinement region, and having a layered structure capable of forming 2-dimensional carriers between the current confinement region and the second electrode, in which a current flowing from the electrode to the current confinement region has a component in the horizontal direction relative to the surface of the substrate and is conducted mainly by way of the channel for the 2-dimensional carrier gas, whereby the device resistance can be reduced greatly to provide high speed optical module using the surface emitting laser improved in the performance operating at a high speed of 10 Gb/s or more.

Vertical cavity surface emitting lasers, optical modules and systems

A fabrication process for a semiconductor device including a plurality of semiconductor layers, the plurality of semiconductor layers including at least a nitrogen-containing alloy semiconductor Al.sub.a Ga.sub.b In.sub.1-a-b N.sub.x P.sub.y As.sub.z Sb.sub.1-x-y-z (0.ltoreq.a.ltoreq.1, 0.ltoreq.b.ltoreq.1, 0&lt;x&lt;1, 0.ltoreq.y&lt;1, 0.ltoreq.z&lt;1), and a method of making the semiconductor device and apparatus. For at least two semiconductor layers out of the plurality of semiconductor layers, a value of lattice strain of said at least two semiconductor layers is set at less than a critical strain at which misfit dislocations are generated at an interface between said two adjacent semiconductor layers. In a method for manufacturing a semiconductor device, Al, Ga, In, N, P, As and Sb as materials are prepared as materials for a semiconductor device, and a plurality of semiconductor layers are epitaxially grown by using said materials, including a layer of nitrogen-containing alloy semiconductor Al.sub.a Ga.sub.b In.sub.1-a-b N.sub.x P.sub.y As.sub.z Sb.sub.1-x-y-z (0.ltoreq.a.ltoreq.1, 0.ltoreq.b.ltoreq.1, 0&lt;x&lt;1, 0.ltoreq.y&lt;1, 0.ltoreq.z&lt;1) using nitrogen radical as nitrogen material, in a vacuum of substantially 10.sup.-2 Torr or higher.

Fabrication method for AlGaIn NPAsSb based devices

Disclosed is a vertical cavity surface emitting laser providing mirrors at least one of which has a high reflectivity to be obtained with a small number of pairs each comprising a semiconductor low-refractivity layer and a semiconductor high-refractivity layer, (1) in which GaAs is used for a substrate and Al, In and P are used as main elements for making the low-refractivity layers lattice-matching the GaAs substrate; (2) in which Ga, In, N and As are used as main elements of the high-refractivity layers; (3) in which GaAs is used for a substrate, Ga, In, N and As are used as main elements for making an active layer and the mirrors lattice-match the GaAs substrate.

Vertical cavity surface emitting laser, optical transmitter-receiver

A hetero crystalline structure consisting of semiconductor materials of a zincblende-structure and wurtzite-structure. For example, formed on a semiconductor substrate having a crystal face of (100) of the zincblende structure is a semiconductor material of the wurtzite-structure in its bulk state as a film of the same zincblende-structure as the semiconductor substrate.

Hetero crystalline structure and semiconductor device using it

An optielectronic device comprising a substrate crystal whose crystal plane is a (n11) plane tilted from the (100) plane toward the [110] direction, or [110] direction where (n&gt;1). When the substrate is applied to an AlGaInP semiconductor laser, the optical device can be cleaved into a rectangular shape, as in the case of a (100) substrate crystal, resulting in easy handling of the chips and also is effective for making the lasting wavelength shorter, lowering the threshold current density for lasing, improving the continuous lasing temperature, etc. Furthermore, semiconductor lasers of different lasing wavelengths can be prepared under good control. Furthermore, a doping efficiency having no dependence on a tilt angle can be obtained by proper selection of a dopant. For example, Si is suitable as an n-type dopant entering sites of group III atom on an (n11) A plane (n.gtoreq.2).

Optoelectronic devices

A semiconductor laser having a double hetero structure comprises a cladding layer of In.sub.1-x-y Ga.sub.x Al.sub.y P.sub.1-z As.sub.z (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.z.ltoreq.0.5, 0.5.ltoreq.x+y.ltoreq.1) and an active layer of a strained-layer-superlattice of In.sub.1-x-y Ga.sub.x Al.sub.y P.sub.1-z As.sub.z (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.z.ltoreq.1, 0.ltoreq.x+y.ltoreq.1) system, thus enabling the lasing of wavelength ranges from infra-red to green.

Semiconductor laser device

An opto-electronic device has an atomic layer superlattice semiconductor comprising different semiconductor materials periodically piled up, each material having an atomic layer thickness. The superlattice semiconductor has a bandgap different from an alloy semiconductor having equivalently the same composition as the former. In a semiconductor laser, as clad layers, the atomic layer superlattice semiconductor having equivalently the same composition as a Zn.sub.0.42 Cd.sub.0.58 S alloy semiconductor and a larger bandgap than the later is used, and a ZnSe.sub.0.94 S.sub.0.06 alloy semiconductor as an active layer is located between the cladding layers. The double-hetero structure semiconductor laser thus provided can perform the lasing at 470 nm at room temperature.

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Kodaira, Japan

Masahiko Kondow