Toyoda Gosei Co., Ltd.

Kabushiki Kaisha Toyota Chuo Kenkyusho

Masanobu Senda

Naoki Shibata

Jun Ito

Toshiaki Chiyo

Shizuyo Asami

Hiroshi Watanabe

Shinya Asami

Yasuhiko Ogisu

Toshiyasu Ito

Toshimasa Hayashi

Toshikazu Funahashi

Kazuki Nishijima

Mamoru Kato

Shigeyuki Takahashi

Takaaki Mori

Toshiya Uemura

Koichi Goshonoo

Masayoshi Kosaki

Koji Hirata

Takahiko Asaoka

Mitsuhiro Inoue

Masaki Hashimura

Hideki Omoya

A field-effect transistor which comprises a buffer layer and a barrier layer each of which is made of a Group III nitride compound semiconductor and has a channel at the interface inside of the buffer layer to the barrier layer, wherein the barrier layer has multiple-layer structure comprising an abruct interface providing layer which composes the lowest semiconductor layer in said barrier layer and whose composition varies rapidly at the interface of said buffer layer, and an electrode connection plane providing layer which constructs the uppermost semiconductor layer and whose upper surface is formed flat.

Field-effect transistor, semiconductor device, a method for manufacturing them, and a method of semiconductor crystal growth

A foam-holding bodyhaving a large difference in refractive index between foamsand the surrounding material is disposed on the major light extraction surface of the sapphire substrate. The foam-holding bodyhas translucency to light of a light-emitting wavelength and is formed of a material such as a silicone or the like, having a refractive index equal to or more than 1.77, and includes a foam-holding layer holding a plurality of foams made of an air or an inactive gas having a refractive index of about one. Therefore, when the light emitted in the light-emitting portion scatters in the foam-holding body, the spread of the scattered light becomes wide, which restricts repetition of the total reflection in the light-emitting device to improve an efficiency of the light extraction.

Light-emitting device

A method including the steps of: modifying at least one part of a sapphire substrate by dry etching to thereby form any one of a dot shape, a stripe shape, a lattice shape, etc. as an island shape on the sapphire substrate; forming an AlN buffer layer on the sapphire substrate; and epitaxially growing a desired Group III nitride compound semiconductor vertically and laterally so that the AlN layer formed on a modified portion of the surface of the sapphire substrate is covered with the desirably Group III nitride compound semiconductor without any gap while the AlN layer formed on a non-modified portion of the surface of the sapphire substrate is used as a seed, wherein the AlN buffer layer is formed by means of reactive sputtering with Al as a target in an nitrogen atmosphere.

Process for producing group III nitride compound semiconductor

A semiconductor light emitting element that is made by using the lateral growth function of semiconductor crystal while providing an ELO mask on a crystal growth surface of a crystal growth substrate. At least part of a sidewall of the ELO mask is provided with an inclined plane that is inclined to the crystal growth surface such that the semiconductor crystal to be formed on the ELO mask substantially has no void.

Semiconductor light emitting element and method of making same

An insulation filmmade of SiOis formed on a p-type layerand a multiple thick film positive electrodewhich is a metal film formed through metal deposition, is formed on the insulation filmand on the p-type layerat the central portion of which has a window and is exposed. The insulation filmhas a thickness of one fourth multiple of emission wavelength. Thickness of the insulation filmis generally determined by multiplying one fourth of intramedium emission wavelength by an odd number. By interference effect, directivity of radiated light along the optical axis direction can be improved.

Semiconductor light-emitting device

A Group III nitride compound semiconductor light-emitting element has a reflecting surface on a side opposite to a main light-emitting surface of the element viewed from a light-emitting layer. The reflecting surface is inclined to surfaces of growth of semiconductor layers. Light emitted from the light-emitting layer is reflected by the reflecting surface, so that the reflected light emerges from side surfaces of the light-emitting element to the outside without passing through the semiconductor layers (particularly, the light-emitting layer).

Group III nitride compound semiconductor light-emitting element

A first group III nitride compound layer, which is formed on a substrate by a method not using metal organic compounds as raw materials, is heated in an atmosphere of a mixture gas containing a hydrogen or nitrogen gas and an ammonia gas, so that the crystallinity of a second group III nitride compound semiconductor layer formed on the first group III nitride compound layer is improved. When the first group III nitride compound layer is formed on a substrate by a sputtering method, the thickness of the first group III nitride compound layer is set to be in a range of from 50 &#x212b; to 3000 &#x212b;.

Group III nitride compound semiconductor device and method of producing the same

In an LED, the area of contact between an ohmic electrode formed on a contact layer and the contact layer serves as an effective light-emitting area of a light-emitting layer. Therefore, while the area of contact between the ohmic electrode and the contact layer is kept small, a seat electrode is interposed so that the seat electrode is connected to a circuit wiring on a wiring board by a ball electrode being contact with the seat electrode at an area larger than the area. As a result, the size necessary for forming the ball electrode can be secured easily and the light-emitting area of the light-emitting layer in the LED can be reduced sufficiently. Accordingly, a capacitance component formed by clamping the light-emitting portion of the light-emitting layer can be reduced, so that a time constant at a leading edge of luminance and a time constant at a trailing edge of luminance can be reduced sufficiently to obtain a high speed.

Communication device

The invention is to realize such a semiconductor light-emitting element which is higher in external quantum efficiency than an existing LED, and lower in production cost than an existing semiconductor laser. The light transmission insulating film is formed on a continuously incline face comprising the semiconductor layers having an opening angle etched in right angled V. The V shape incline is formed by a known technique, and both left and right inclined faces have the angle of 45&#xb0;. Depending on the length of &#x3b4; or the position of the light reflecting portion, probability that the light in duration of resonance is reflected may be made optimum or preferable. According to this structure, it is no longer necessary to carry out processing treatments of high degree, high precision, or high cost such as, e.g., multi-layered film coating in a resonance direction, and it is possible to structure the semiconductor light-emitting element having a resonating mechanism as a resonator though not forming end faces of high cost.

Semiconductor light-emitting element

A group III nitride compound semiconductor device has a substrate and an AlN single crystal layer formed on the substrate. The AlN single crystal layer has a thickness of from 0.5 to 3 &#x3bc;m and has a substantially flat surface. The half-value width of an X-ray rocking curve of the AlN single crystal layer is not longer than 50 sec. In another device, a group III nitride compound semiconductor layer having a thickness of from 0.01 to 3.2 &#x3bc;m is grown at a temperature of from 1000 to 1180&#xb0; C. on a sapphire substrate having a surface nitride layer having a thickness of not larger than 300 &#x212b;.

Group III nitride compound semiconductor device and producing method therefor

A titanium layer and a titanium nitride layer are successively laminated on a substrate and a group III nitride compound semiconductor layer is further formed thereon. When the titanium layer is removed in the condition that a sufficient film thickness is given to the titanium nitride layer, a device having the titanium nitride layer as a substrate is obtained.

Group III nitride compound semiconductor device

A separator layer of Ti is formed on an auxiliary substrate of sapphire or the like. An undercoat layer of TiN is formed on the separator layer. The undercoat layer is provided so that a Group III nitride compound semiconductor layer can be grown with good crystallinity on the undercoat layer. TiN is sprayed on the undercoat layer to form a thermal spray depositing layer. Then, the separator layer is chemically etched to reveal the undercoat layer. Then, a Group III nitride compound semiconductor layer is grown on a surface of the undercoat layer.

III group nitride based semiconductor element and method for manufacture thereof

An AlN layer having a surface of a texture structure is formed on a sapphire substrate. Then, a growth suppressing material layer is formed on the AlN layer so that the AlN layer is partially exposed to the outside. Then, group III nitride compound semiconductor layers are grown on the AlN layer and on the growth suppressing material layer by execution of an epitaxial lateral overgrowth method. Thus, a group III nitride compound semiconductor device is produced. An undercoat layer having convex portions each shaped like a truncated hexagonal pyramid is formed on a substrate. Group III nitride compound semiconductor layers having a device function are laminated successively on the undercoat layer.

Group III nitride compound semiconductor device and method for producing the same

A preferred condition for forming a Group III nitride compound semiconductor layer on a substrate by a sputtering method is proposed. When a first Group III nitride compound semiconductor layer is formed on a substrate by a sputtering method, an initial voltage of a sputtering apparatus is selected to be not higher than 110% of a sputtering voltage.

Method for producing group-III nitride compound semiconductor device

A first group III nitride compound layer, which is formed on a substrate by a method not using metal organic compounds as raw materials, is heated in an atmosphere of a mixture gas containing a hydrogen or nitrogen gas and an ammonia gas, so that the crystallinity of a second group III nitride compound semiconductor layer formed on the first group III nitride compound layer is improved. When the first group III nitride compound layer is formed on a substrate by a sputtering method, the thickness of the first group III nitride compound layer is set to be in a range of from 50 &angst; to 3000 &angst;.

Growing community of inventors

Aichi, Japan

Masanobu Senda