Hitachi, Ltd.

Takao Kuroda

Takashi Kajimura

Jun-ichi Umeda

Hiroyoshi Matsumura

Yasuhiro Shiraki

Naoki Chinone

Tsukuru Ohtoshi

Yasutoshi Kashiwada

Akiyoshi Watanabe

Takeshi Shimano

Makoto Okai

Shinji Tsuji

Michiharu Nakamura

Tomoyoshi Mishima

Kunio Aiki

Makoto Morioka

Yoshifumi Katayama

Shigeo Yamashita

Takao Miyazaki

Yasushi Sawada

Motohisa Hirao

Hisao Nakashima

Akio Ohishi

Atsuko Niwa

Hiroshi Matsuda

Kiichi Ueyanagi

Naoyuki Tamura

Eiichi Maruyama

Sumio Okuno

Shinjiro Ueda

Kenji Hiruma

Hideaki Kamohara

Yoshimasa Murayama

Kazumasa Fujioka

Muneo Mizumoto

Hirobumi Ouchi

Katsutoshi Saito

Sumio Yamaguchi

An information processor of a high reliability and a high recording density, and a blue color, blue-violet color and violet color based semiconductor light emitting device operable at a low threshold current density, used for the same, are provided. An optical information processor of a high reliability and a high recording density enables a moving picture, such as a high-definition television picture, to be recorded and reproduced satisfactorily. A barrier layer in a quantum-well active layer of a semiconductor light emitting device is doped with n-type impurities at a high density. Alternatively, the face orientation of a quantum-well active layer of a semiconductor light emitting device is a plane inclined from the (0001) plane, whereby the threshold current value of the semiconductor light emitting device can be decreased. The semiconductor light emitting device is typified by a gallium nitride based compound semiconductor laser device.

Optical information processing equipment and semiconductor light emitting device suitable therefor

Optical information processor and semiconductor light emitting device suitable for the same

Disclosed is a semiconductor device comprising an undoped GaAs layer, an intermediate undoped layer and an undoped Ga.sub.1-x Al.sub.x As layer which are successively provided on a substrate made of a semiinsulating GaAs crystal; the intermediate undoped layer being an undoped In.sub.y Ga.sub.1-y As layer, an undoped GaAs.sub.1-z Sb.sub.z layer, a superlattice layer which includes an undoped In.sub.y Ga.sub.1-y As layer and an undoped GaAs.sub.1-z Sb.sub.z layer, a superlattice layer which includes an undoped In.sub.y Ga.sub.1-y As layer and an undoped GaAs layer, or a superlattice layer which includes an undoped GaAs.sub.1-z Sb layer and an undoped GaAs layer. When applied to a high electron mobility transistor, this semiconductor device affords a high current and a high speed and has the merit of a small dispersion in the threshold voltage thereof.

Semiconductor device

A semiconductor device such as a semiconductor laser device or a transistor which is small in both threshold current and leakage current and exhibits no increase with time in the threshold current and leakage current can be obtained by incorporating pnp or npn junctions in a buried layer which coats an active region containing InGaAsP, forming the mid layer of the junctions with InGaAsP, adjusting the conductivity type of the mid layer with an implanted ion and specifying the energy band width of a semiconductor constituting the mid layer.

Semiconductor devices

Disclosed is a semiconductor device comprising a first semiconductor layer, a second semiconductor layer, and a third semiconductor layer which is formed between the first semiconductor layer and the second semiconductor layer and a band gap of which is narrower than that of each of the first and second layers, so that band discontinuities in conduction bands and valence bands of the three layers form a barrier to the third semiconductor layer, and that a tunneling current can flow through the third semmiconductor layer owing to an internal electric field of the third semiconductor layer.

Electron gas hole gas tunneling transistor device

A semiconductor device in which two sorts of compound semiconductors having unequal lattice constants are joined, is disclosed. Defects such as dislocations attributed to lattice mismatching are avoided by subjecting one of the compound semiconductors to atomic layer doping with an impurity. Owing to this construction, it is permitted to combine the optimum materials as the compound semiconductors, and the semiconductor device has its performance improved and its design versatility expanded.

Semiconductor device and method of manufacturing the same

When a semiconductor device is produced by growing epitaxially a compound semiconductor layer on a Si or Ge substrate, lattice matching between the substrate crystal and the compound semiconductor layer to be formed on the substrate can be improved by ion-implanting an ion species element, which increases the lattice constant of Si or Ge as the substrate, into the Si or Ge substrate in order to increase its lattice constant. In comparison with conventional semiconductor devices using Si or Ge into which ion implantation is not made, the semiconductor device produced by the method described above can improve remarkably its characteristics. In the case of a semiconductor laser device, for example, its threshold value drops drastically and its service life can be prolonged remarkably.

Method of growing heteroepitaxial InP on Si using Sn substrate

There is disclosed a semiconductor device comprising at least first and second semiconductor layers positioned to form a hetero-junction therebetween, such a hetero-junction being adapted to form a channel, means for controlling carriers, and source and drain areas on opposite edges of the channel, wherein the first and second semiconductor layers formed between the source and drain regions have an area containing only 10.sup.16 cm.sup.-3 or less of an impurity; the first semiconductor layer has a wider forbidden band than that of the second semiconductor layer; and further including at least one semiconductor layer having a higher activation efficiency of impurities than that of the first semiconductor layer, with such at least one semiconductor layer being located on the side of the first semiconductor layer not in contact with the second semiconductor layer. A multi-quantum well structure may be used as the higher impurity activation efficiency semiconductor layer. The electrical resistance in the semiconductor area constituting the source and drain regions can be lowered by utilizing such a higher impurity activation efficiency semiconductor layer.

Heterojunction FET with doubly-doped channel

A semiconductor member has a structure wherein a first semiconductor layer is held between second and third semiconductor layers which have forbidden band widths greater than a forbidden band width of the first semiconductor layer, and wherein only the second semiconductor layer which is formed on a side of the first semiconductor layer close to a substrate is doped with impurities. The semiconductor member constructs the depletion type with the first and second semiconductor layers, and the enhancement type with the first and third semiconductor layers. A semiconductor device can be properly formed in the enhancement or depletion type by selectively connecting the semiconductor layers.

Semiconductor member and semiconductor device employing the same

Disclosed herein is a semiconductor laser device including at least an optical confinement region having at least first, second and third semiconductor layers disposed on a semiconductor substrate, wherein the first and third semiconductor layers have refractive indices greater than the refractive index of the second semiconductor layer but have forebidden band gap smaller than that of the second semiconductor layer and the conductivity types of the first and third semiconductor layers are opposite to each other; the second semiconductor layer has a smooth change of its thickness in two directions parallel to a junction surface of the optical confinement region; and a difference exists in the refractive indices of the first and third semiconductor layers.

Buried heterojunction laser

A rotary substrate holder of a molecular beam epitaxy apparatus including leads-cum-posts serving both as leads for passing a current to a heater for heating a substrate and as posts for supporting the heater. By this arrangement, heat transferred from the heater to a bearing disposed in the vicinity of the heater is minimized in amount, thereby prolonging the service life of the holder and minimizing a heat loss thereof.

Rotary substrate holder of molecular beam epitaxy apparatus

Disclosed is a semiconductor laser device having at least an optical confinement region which includes a first semiconductor layer, and second and third semiconductor layers holding the first semiconductor layer therebetween and having a greater band gap and a lower refractive index than those of the first semiconductor layer, the second and third semiconductor layers having conductivity types opposite to each other; characterized in that the relationship between a donor density (N.sub.D .times.10.sup.17 cm.sup.-3) of the n-conductivity type semiconductor layer in the second and third semiconductor layers and a proportion (.GAMMA..sub.n %) of an optical output existing in the n-conductivity type semiconductor layer relative to a total optical output of the laser is set at N.sub.D .times..GAMMA..sub.n .gtoreq.500. Noise characteristics are sharply improved.

Semiconductor laser device

A semiconductor laser device is provided with a semiconductor substrate and at least a semiconductor assembly for optical confinement formed on the substrate which includes an active layer and cladding layers. A first electrode is disposed on the semiconductor assembly and a second electrode is disposed on the semiconductor substrate. To provide a phase-locked semiconductor laser device of high quality, a plurality of regions are provided in the semiconductor assembly which, in effect, cause a variation of a complex refractive index for a laser beam in a direction intersecting with a traveling direction of the laser beam. These regions can be discretely disposed over or under the active layer and give rise to a nonlinear interaction between adjacent laser emission regions formed by the plurality of regions.

Phase-locked semiconductor laser device

Growing community of inventors

Kokubunji, Japan

Takao Kuroda