Nec Corporation

Other

Masaaki Nido

Akitaka Kimura

Atsushi Yamaguchi

Masaru Kuramoto

Haruo Sunakawa

Isao Tomita

Taro Kaneko

Yukihiro Hisanaga

Akira Suzuki

Akira Usui

Akihisa Tomita

Yasunori Mochizuki

A thermal contraction stress and a residual contraction stress caused by a difference between the linear expansion coefficients of an optical element unit and a carrier are reduced as much as possible. An optical module includes an optical element unit including optical elements requiring a stress control, and a carrier which supports the optical element unit. As the carrier is made of a material having the same property as that of the substrate material of the optical element, the thermal contraction stress is reduced.

Optical module

Distortion of the temperature control element and the package by thermal deformation or mechanical deformation is prevented from being transmitted to the optical element as stress, and at the same time, constant temperature control of the optical element is realized. An optical element unit including an optical element that requires temperature control and an optical component that does not require temperature control, and a temperature control element for performing temperature adjustment of the optical element are arranged. The temperature control element performs temperature adjustment control of the optical element through a region mounted with the optical component of the optical element unit.

The present invention provides a semiconductor device having a semiconductor multi-layer structure which includes at least an active layer having at least a quantum well, and the active layer further including at least a luminescent layer of InAlGaN (0&#x3c;x&#x3c;1, 0&#x2266;y&#x2266;0.2), wherein a threshold mode gain of each of the at least quantum well is not more than 12 cm, and wherein a standard deviation of a microscopic fluctuation in a band gap energy of the at least luminescent layer is in the range of 75 meV to 200 meV.

Nitride based semiconductor light-emitting device

A nitride based semiconductor photo-luminescent device has an active layer having a quantum well structure. The active layer has both a high dislocation density region and a low dislocation density region that is lower in dislocation density than the high dislocation density region, wherein the low dislocation density region includes a current injection region into which a current is injected, and the active layer is less than 1&#xd7;10cmin impurity concentration.

Nitride based semiconductor photo-luminescent device

Gallium nitride based compound semiconductor light-emitting device

For forming a contact electrode to an n-type contact layer of a gallium nitride-based compound semiconductor, the n-type contact layer of the gallium nitride-based compound semiconductor is exposed to an oxygen plasma to form an oxygen-doped surface layer in a surface of the n-type contact layer, and then, an electrode metal is formed on the oxygen-doped surface layer. With this arrangement, an n-type contact electrode having a low specific contact resistance is obtained with good reproducibility, with performing no annealing after formation of the electrode metal.

Contact electrode for n-type gallium nitride-based compound semiconductor and method for forming the same

A semiconductor device and method of forming a current block layer structure includes the steps of providing dielectric stripe masks defining at least a stripe-shaped opening on a surface of a compound semiconductor region having a hexagonal crystal structure, and selectively growing at least a current block layer of a compound semiconductor having the hexagonal crystal structure on the surface of the compound semiconductor region by use of the dielectric stripe masks.

Gallium nitride based compound semiconductor laser and method of forming the same

Contact electrode for N-type gallium nitride-based compound semiconductor and method for forming the same

A method of crystal growth of a GaN layer with an extremely high surface planarity over a GaAs substrate is provided, wherein a GaAs substrate is heated to a temperature in the range of 600.degree. C. to 700.degree. C. without supplying any group-V element including arsenic to form a Ga-rich surface on the GaAs substrate, before a first source material including N and a second source material including Ga are supplied along with a carrier gas onto a surface of the GaAs substrate to form a GaN layer over the GaAs substrate.

Method of crystal growth of a GaN layer over a GaAs substrate

Disclosed is a method of growing 4 gallium nitride-based crystal by vapor phase epitaxy, suitable for mass production, without the necessity of thermal processing after completion of the crystal growth. The temperature of the substrate crystal immediately after completion of the crystal growth is 700.degree. C. or higher, and cooling of the substrate crystal at 700.degree. C. or lower after completion of the crystal growth is performed in an atmosphere of a hydrogen-fee carrier gas.

Method for growing p-type gallium nitride based compound semiconductors

A crystal growth method for growing on a gallium arsenide (GaAs) substrate a gallium nitride (GaN) film which is good in surface flatness and superior in crystallinity. According to the method, a GaAs substrate having a surface which is inclined with respect to the GaAs(100) face is used. The inclination angle of the substrate surface is larger than 0 degree but smaller than 35 degrees with respect to the GaAs(100) face. The inclination direction of the substrate surface is within a range of an angular range from the �0,0,1! direction of GaAs to the �0,-1,0! direction past the �0,-1,1! direction and angles less than 5 degrees on opposite sides of the angular range around an �1,0,0! direction of gallium arsenide taken as an axis, or within another range crystallographically equivalent to the range. The GaN layer is formed on the surface of the GaAs substrate preferably by hydride vapor deposition method.

Crystal growth method for gallium nitride films

In a heterostructure III-V nitride semiconductor device, an InP substrate has a surface having a sloped angle of 0.degree. to 16.degree. with respect to a (100) surface thereof. At least one GaN layer is formed on the InP substrate.

Heterostructure III-V nitride semiconductor device including InP

A gallium nitride type compound semiconductor light emitting element, such as a semiconductor laser, a light emitting diode is constructed by forming an In.sub.0.06 Ga.sub.0.94 N buffer layer, an n-type In.sub.0.06 Ga.sub.0.94 N clad layer, an n-type In.sub.0.06 Al.sub.0.15 Ga.sub.0.79 N clad layer, an undoped GaN active layer having layer thickness of 50 nm, a p-type In.sub.0.06 Al.sub.0.15 Ga.sub.0.79 N clad layer and a p-type In.sub.0.06 Ga.sub.0.94 N cap layer on a (0001) azimuth sapphire substrate. A p-side electrode is formed on the p-type In.sub.0.06 Ga.sub.0.94 N cap layer, and an n-side electrode is formed on the n-type In.sub.0.06 Ga.sub.0.94 N clad layer. In the construction set forth above, a greater thickness for the active layer is provided. Also, tensile strain is applied to the active layer. Light is taken out in parallel direction to the substrate. This threshold current of the semiconductor laser is lowered and light emitting efficiency of the light emitting diode is improved.

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Tokyo, Japan

Masaaki Nido