Hitachi, Ltd.

Hitachi Electronics Co., Ltd.

Kazuhiro Kurata

Yuichi Ono

Kazuhiro Ito

Makoto Morioka

Mitsuhiro Mori

Masahiko Kawata

Masao Kawamura

Masaaki Aoki

Hirobumi Ouchi

Hiroshi Matsuda

Satoshi Nakamura

Naoki Chinone

Sachio Ishioka

Masahiko Ogirima

Hisao Nakashima

Yutaka Takeda

Masahiro Ichiki

Takeo Takahashi

Mitshiuro Mori

Ginro Takemura

Youichi Yasuda

Kozi Honma

Makoto Sakamoto

Yoshiteru Keikoin

Yasushi Koga

Disclosed is a photo-detective semiconductor device having, on a predetermined semiconductor substrate, at least a first semiconductor layer which exhibits a first conductivity type, a second semiconductor layer which is disposed on said first semiconductor layer, which has a forbidden band gap greater than that of said first semiconductor layer and which exhibits the first conductivity type, and a p-n junction which is formed by a region disposed in said second semiconductor layer and exhibiting a second conductivity type; characterized by comprising a third semiconductor layer which is disposed on said second semiconductor layer, which exhibits the first conductivity type and which has a surface protective function. The third semiconductor layer is usually made of a group III-V compound semiconductor of a quaternary system. By way of example, in a case where the first semiconductor layer is formed of InGaAsP and where the second semiconductor layer is formed of InP, the third semiconductor layer is made of InGaAsP, InGaAs or the like. A photo-detective semiconductor device of low dark current can be provided.

Photo semiconductor device

An optical semiconductor device includes a light emitting element disposed on a silicon sub-mount having a light receiving element formed in a surface region. By virtue of integral arrangement of the light emitting element and the light receiving element, a single lens can be used for both optical transmission and optical reception, whereby an optical communication system can be manufactured very inexpensively. Further, transmission and reception can be carried out simultaneously.

Optical semiconductor device

A planar-type pleochroic light emitting diode and a method of fabricating the same are disclosed, the diode allowing from a single chip a plurality of light emissions having different center wavelengths. Impurity diffusion is carried out by use of a film having a masking effect to an impurity and a different film partially non-uniform in thickness having no masking effect to the impurity to form a plurality of diffusion regions having different depths. The diode has excellent coupling with an optical fiber, can be easily fabricated and is suitable for use in optical multiplex communication.

Pleochroic light emitting diode and method of fabricating the same

In a prior-art injection type light emitting device which is constructed so that a predetermined range of a p-n junction formed by a semiconductor substrate and an epitaxial layer provided thereon may radiate, a radiation region in the p-n junction becomes larger in area than the region into which current is introduced, on account of the current spreading phenomenon. The construction of a light emitting device free from the phenomenon and a method for manufacturing the light emitting device are disclosed.

Light emitting devices

A light emitting semiconductor device wherein a p-n junction is defined by a ditch and wherein the ditch either extends to a low resistance layer or is away from the low resistance layer at most 1/2 of the width of the ditch is disclosed. It has the merit that the near field pattern is much more uniform than in a prior-art device.

Light emitting semiconductor device

A semiconductor layer for supporting a diode chip of a semiconductor laser is formed to be higher than a semiconductor layer containing a current-conducting region, whereby stresses acting on the diode chip by mounting the diode chip are relieved to prevent degradation of performance and reduced life of the semiconductor laser.

Semiconductor laser

A light emitting element made of a group III - V compound semiconductor has a p-n junction and a hetero-junction which are identical; the mixing ratio (band gap) of a p-type layer on the light emitting side is sufficiently smaller than that of an n-type layer on the opposite side. The semiconductor light-emitting element is especially useful as a light source, for optical communications, photoexcitation, etc.

Semiconductor light-emitting element

In a method for making a light emitting device having hemispherical dome type geometry, a p-conductivity type and then an n-conductivity type layer are successively grown epitaxially on a substrate made of a mixed compound semiconductor crystal having a band gap wider than the two above-mentioned layers. A surface portion of these epitaxially grown layers, which is not covered by a mask deposited on the n-conductivity type layer at a position where a p-n junction is to be formed, is doped with p-conductivity type impurities so that a small n-conductivity type region is surrounded by a region converted into p-conductivity type. The other side of the crystal is formed into a hemispherical shape so that the n-conductivity type region is located at the central portion of the hemisphere.

Light emitting semiconductor device and a method for making the same

A longitudinal epitaxial growth device for making a mixed crystal of III.sub.b -V.sub.b group intermetallic compound semiconductor in which a means for inverting the reaction gas flow is disposed between the gallium source and the substrate, the height of the device is reduced, and the length of the gas mixing band is made sufficiently long.

Epitaxial growth device

In an epitaxial growth process for compound semiconductor crystals in a liquid phase, a substrate crystal is brought into contact with an etching solution containing as solute a predetermined amount of at least one constituent of the substrate crystal, which is smaller than that of a saturated solution, after heating them at a temperature for crystal growth. The substrate crystal is kept in contact with the solution during a period of time sufficient to remove a surface portion of the substrate crystal. Then the substrate crystal is brought into contact with a solution for crystal growth containing a substance to be grown as solute and a crystal of the substance is grown epitaxially on an exposed clean surface of the substrate crystal.

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Hachioji, Japan

Kazuhiro Kurata