Mitsubishi Cable Industries, Ltd.

Mitsubishi Chemical Corporation

Other

Hiroaki Okagawa

Kazuyuki Tadatomo

Yoichiro Ouchi

Masahiro Koto

Shin Hiraoka

Takahide Joichi

Shinichi Watabe

Kazumasa Hiramatsu

Hirokazu Taniguchi

Youichiro Ohuchi

Toshihiko Shima

Keiji Miyashita

Takayuki Hashimoto

Kazuhiko Kagawa

Yoshihito Satou

Hiroaki Sakuta

Takashi Tsunekawa

Hiromitsu Kudo

Tomoo Yamada

Nobuhiko Sawaki

Sumito Shimizu

Yutaka Hamamura

Takumi Shibata

Katsunori Yahashi

Teruhisa Nakai

Tadatomo Kazuyuki

Seong-Jin Kim

Tsuyoshi Takano

A substrate for epitaxial growth of the present invention comprises: a single crystal part comprising a material different from a GaN-based semiconductor at least in a surface layer part; and an uneven surface, as a surface for epitaxial growth, comprising a plurality of convex portions arranged so that each of the convex portions has three other closest convex portions in directions different from each other by 120 degrees and a plurality of growth spaces, each of which is surrounded by six of the convex portions, wherein the single crystal part is exposed at least on the growth space, which enables a c-axis-oriented GaN-based semiconductor crystal to grow from the growth space.

Substrate for epitaxial growth, process for manufacturing GaN-based semiconductor film, GaN-based semiconductor film, process for manufacturing GaN-based semiconductor light emitting element and GaN-based semiconductor light emitting element

A white light-emitting semiconductor device having improved reproducibility of bright red. The device outputs light having a blue component, a green component, and a red component. Each of the light components (blue, green, and red) is based on a light-emitting semiconductor element and/or a phosphor that absorbs light emitted by a light-emitting semiconductor element and emits light through wavelength conversion. The outputted light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and the intensity at a wavelength of 580 nm of the outputted light, which has been normalized with respect to luminous flux, is 80-100% of the intensity at a wavelength of 580 nm of standard light for color rendering evaluation, which has been normalized with respect to luminous flux.

White light-emitting semiconductor devices

A nitride semiconductor light-emitting diode elementincludes a nitride semiconductor layerhaving a bottom surface and an upper surface and containing a light emitting layerinside, and a supporting substratemade from a metal is bonded to the bottom surface of the nitride semiconductor layer. A light reflecting depression Ato reflect light generated in the light emitting layeris formed in the bottom surface of the nitride semiconductor layer. According to the nitride semiconductor light-emitting diode element, since the light generated from the light emitting layerand propagated in the nitride semiconductor layerin a layer direction is reflected by the light reflecting depression Aand its travel direction is changed, the ratio of the light incident upon the upper surface of the nitride semiconductor layerwithin a critical angle is increased. Thus, light extraction efficiency is improved as compared with a conventional nitride semiconductor light-emitting diode element.

Nitride semiconductor light-emitting diode device

A white light-emitting semiconductor device having improved reproducibility of bright red. The device outputs light having a blue component, a green component, and a red component. Each of the light components (blue, green, and red) consists of a light-emitting semiconductor element and/or a phosphor that absorbs light emitted by a light-emitting semiconductor element and emits light through wavelength conversion. The outputted light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and the intensity at a wavelength of 580 nm of the outputted light, which has been normalized with respect to luminous flux, is 80-100% of the intensity at a wavelength of 580 nm of standard light for color rendering evaluation, which has been normalized with respect to luminous flux.

A light emitting device is constituted by flip-chip mounting a GaN-based LED chip. The GaN-based LED chip includes a light-transmissive substrate and a GaN-based semiconductor layer formed on the light-transmissive substrate, wherein the GaN-based semiconductor layer has a laminate structure containing an n-type layer, a light emitting layer and a p-type layer in this order from the light-transmissive substrate side, wherein a positive electrode is formed on the p-type layer, the electrode containing a light-transmissive electrode of an oxide semiconductor and a positive contact electrode electrically connected to the light-transmissive electrode, and the area of the positive contact electrode is half or less of the area of the upper surface of the p-type layer.

Light emitting device using GaN LED chip

A first conductive film-of a light-transmissive conductive oxide filmand a positive pad electrodeare electrically connected through a second conductive film-of the light-transmissive conductive oxide filmin a GaN-based LED element. A contact resistance of the light-transmissive conductive oxide filmwith a p-type layer-in a first contact portionA is lower than in a second contact portionB, so that a current supplied from the positive pad electrodeto the p-type layer-through the conductive oxide filmflows to the p-type layer-mainly through the first contact portionA.

GaN LED element and light emitting device having a structure to reduce light absorption by a pad electrode included therein

The object of the present invention is to provide a semiconductor element containing an n-type gallium nitride based compound semiconductor and a novel electrode that makes an ohmic contact with the semiconductor. The semiconductor element of the present invention has an n-type Gallium nitride based compound semiconductor and an electrode that forms an ohmic contact with the semiconductor, wherein the electrode has a TiW alloy layer to be in contact with the semiconductor. According to a preferable embodiment, the above-mentioned electrode can also serve as a contact electrode. According to a preferable embodiment, the above-mentioned electrode is superior in the heat resistance. Moreover, a production method of the semiconductor element is also provided.

Semiconductor element and method for manufacturing same

A growth plane of substrateis processed to have a concavo-convex surface. The bottom of the concave part may be masked. When a crystal is grown by vapor phase growth using this substrate, an ingredient gas does not sufficiently reach the inside of a concave partand therefore, a crystal growth occurs only from an upper part of a convex partAs shown in FIG.(), therefore, a crystal unitoccurs when the crystal growth is started, and as the crystal growth proceeds, films grown in the lateral direction from the upper part of the convex partas a starting point are connected to cover the concavo-convex surface of the substrateleaving a cavityin the concave part, as shown in FIG.(), thereby giving a crystal layerwhereby the semiconductor base of the present invention is obtained. In this case, the part grown in the lateral direction, or the upper part of the concave parthas a low dislocation region and the crystal layer prepared has high quality. The manufacturing method of the semiconductor crystal of the present invention divides this semiconductor base into the substrateand the crystal layerat the cavity part thereof to give a semiconductor crystal.

Semiconductor base and its manufacturing method, and semiconductor crystal manufacturing method

A growth plane of substrateis processed to have a concavo-convex surface. The bottom of the concave part may be masked. When a crystal is grown by vapor phase growth using this substrate, an ingredient gas does not sufficiently reach the inside of a concave partand therefore, a crystal growth occurs only from an upper part of a convex part. As shown in FIG.(), therefore, a crystal unitoccurs when the crystal growth is started, and as the crystal growth proceeds, films grown in the lateral direction from the upper part of the convex partas a starting point are connected to cover the concavo-convex surface of the substrateleaving a cavityin the concave part, as shown in FIG.(), thereby giving a crystal layerwhereby the semiconductor base of the present invention is obtained. In this case, the part grown in the lateral direction, or the upper part of the concave parthas a low dislocation region and the crystal layer prepared has high quality. The manufacturing method of the semiconductor crystal of the present invention divides this semiconductor base into the substrateand the crystal layerat the cavity part thereof to give a semiconductor crystal.

As shown in FIG.(), substratehaving a growth plane having a concavo-convex surface is used. When GaN group crystal is vapor phase grown using this substrate, the concavo-convex shape suppresses growth in the lateral direction and promotes growth in the C axis direction, thereby affording a base surface capable of forming a facet plane. Thus, as shown in FIG.(), a crystal having a facet plane is grown in a convex part, and a crystal is also grown in a concave part. When the crystal growth is continued, the films grown from the convex part and the concave part are joined in time to cover a concavo-convex surface and become flat as shown in FIG.(). In this case, an area having a low a dislocation density is formed in the upper part of the convex part where facet plane was formed, and the prepared film has high quality.

Semiconductor base material and method of manufacturing the material

Concaves and convexesare formed by processing the surface layer of a first layer, and second layerhaving a different refractive index from the first layer is grown while burying the concaves and convexes (or first crystalis grown as concaves and convexes on crystal layer S to be the base of the growth, and second crystalis grown, which has a different refractive index from the first crystal). After forming these concavo-convex refractive index interfaces(), an element structure, wherein semiconductor crystal layers containing a light-emitting layer A are laminated, is formed. As a result, the light in the lateral direction, which is generated in the light-emitting layer changes its direction by an influence of the concavo-convex refractive index interface and heads toward the outside. Particularly, when an ultraviolet light is to be emitted using InGaN as a material of a light-emitting layer, a quantum well structure is employed and all the layers between the quantum well structure and the low temperature buffer layer are formed of a GaN crystal, removing AlGaN. The quantum well structure preferably consists of a well layer made of InGaN and a barrier layer made of GaN, and the thickness of the barrier layer is preferably 6 nm&#x2013;30 nm.

GaN group semiconductor light-emitting element with concave and convex structures on the substrate and a production method thereof

A growth plane of substrateis processed to have a concavo-convex surface. The bottom of the concave part may be masked. When a crystal is grown by vapor phase growth using this substrate, an ingredient gas does not sufficiently reach the inside of a concave part, and therefore, a crystal growth occurs only from an upper part of a convex part. As shown in FIG.(), therefore, a crystal unitoccurs when the crystal growth is started, and as the crystal growth proceeds, films grown in the lateral direction from the upper part of the convex partas a starting point are connected to cover the concavo-convex surface of the substrate, leaving a cavityin the concave part, as shown in FIG.(), thereby giving a crystal layer, whereby the semiconductor base of the present invention is obtained. In this case, the part grown in the lateral direction, or the upper part of the concave parthas a low dislocation region and the crystal layer prepared has high quality. The manufacturing method of the semiconductor crystal of the present invention divides this semiconductor base into the substrateand the crystal layerat the cavity part thereof to give a semiconductor crystal.

The state of a surface of a substrate or a GaN group compound semiconductor film formed on the substrate is modified with an anti-surfactant material and a GaN group compound semiconductor material is supplied by a vapor phase growth method to form dot structures made of the GaN group compound semiconductor on the surface of the semiconductor film , and the growth is continued until the dot structures join and the surface becomes flat. In this case, the dot structures join while forming a cavity on an anti-surfactant region. A dislocation line extending from the underlayer is blocked by the cavity , and therefore, the dislocation density of an epitaxial film surface can be reduced. As a result, the dislocation density of the GaN group compound semiconductor crystal can be reduced without using a masking material in the epitaxial growth, whereby a high quality epitaxial film can be obtained.

Growing community of inventors

Itami, Japan

Hiroaki Okagawa