Toyoda Gosei Co., Ltd.

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Research Development Corporation of Japan

Junichi Umezaki

Masayoshi Koike

Norikatsu Koide

Shinya Asami

Seiji Nagai

Shiro Yamasaki

Naoki Shibata

Takahiro Kozawa

Toshiya Uemura

Shiro Yamazaki

Michinari Sassa

Makoto Asai

Tomohiko Mori

Takeshi Ohwaki

Isamu Akasaki

Hiroshi Amano

In a method of manufacturing a semiconductor light-emitting device involving the steps of: forming a first semiconductor layer; forming a light-emitting layer of superlattice structure by laminating a barrier layer being made of In Ga N (Y1&gE;0) and a quantum well layer being made of In Ga N (Y2>Y1 and Y2>0) on the first semiconductor layer; and forming a second semiconductor layer on the light-emitting layer, an uppermost barrier layer, which will become an uppermost layer of the light-emitting layer, is made thicker than the other barrier layers. Further, at the time of forming the second semiconductor layer, an upper surface of such uppermost barrier layer is caused to disappear so that the thickness of the uppermost barrier layer becomes substantially equal to those of the other barrier layers.

Semiconductor light-emitting device and manufacturing method thereof

In a method of manufacturing a semiconductor light-emitting device involving the steps of: forming a first semiconductor layer; forming a light-emitting layer of superlattice structure by laminating a barrier layer being made of In Ga N (Y &gE;0) and a quantum well layer being made of In Ga N (Y >Y and Y >0) on the first semiconductor layer; and forming a second semiconductor layer on the light-emitting layer, an uppermost barrier layer, which will become an uppermost layer of the light-emitting layer, is made thicker than the other barrier layers. Further, at the time of forming the second semiconductor layer, an upper surface of such uppermost barrier layer is caused to disappear so that the thickness of the uppermost barrier layer becomes substantially equal to those of the other barrier layers.

In a method of manufacturing a semiconductor light-emitting device involving the steps of: forming a first semiconductor layer; forming a light-emitting layer of superlattice structure by laminating a barrier layer being made of In Ga N (Y 0) and a quantum well layer being made of In Ga N (Y Y and Y 0) on the first semiconductor layer; and forming a second semiconductor layer on the light- emitting layer, an uppermost barrier layer, which will become an uppermost layer of the light-emitting layer, is made thicker than the other barrier layers. Further, at the time of forming the second semiconductor layer, an upper surface of such uppermost barrier layer is caused to disappear so that the thickness of the uppermost barrier layer becomes substantially equal to those of the other barrier layers.

In a method of manufacturing a semiconductor light-emitting device involving the steps of: forming a first semiconductor layer; forming a light-emitting layer of superlattice structure by laminating a barrier layer being made of In,Ga,N (Y,&gE;0) and a quantum well layer being made of In,Ga,N (Y,>Y,and Y,>0) on the first semiconductor layer; and forming a second semiconductor layer on the light-emitting layer, an uppermost barrier layer, which will become an uppermost layer of the light-emitting layer, is made thicker than the other barrier layers. Further, at the time of forming the second semiconductor layer, an upper surface of such uppermost barrier layer is caused to disappear so that the thickness of the uppermost barrier layer becomes substantially equal to those of the other barrier layers.

An electrode for a Group III nitride compound semiconductor having p-type conduction that has a double layer structure. The first metal electrode layer comprising, for example, nickel (Ni) and the second metal electrode layer comprising, for example, gold (Au). The Ni layer is formed on the Group III nitride compound semiconductor having p-type conduction, and the Au layer is formed on the Ni layer. Heat treatment changes or reverses the distribution of the elements Ni and Au. Namely, Au is distributed deeper into the Group III nitride compound semiconductor than is Ni. As a result, the resistivity of the electrode is lowered and its ohmic characteristics are improved as well as its adhesive strength.

Methods and devices related to electrodes for p-type group III nitride

A semiconductor light-emitting device involving the steps of: forming a first semiconductor layer; forming a light-emitting layer of superlattice structure by laminating a barrier layer being made of In.sub.Y1 Ga.sub.1-Y1 N (Y1.gtoreq.0) and a quantum well layer being made of In.sub.Y2 Ga.sub.1-Y1 N (Y2&gt;Y1 and Y2&gt;0) on the first semiconductor layer; and forming a second semiconductor layer on the light-emitting layer, an uppermost barrier layer, which will become an uppermost layer of the light-emitting layer, is made thicker than the other barrier layers. Further, at the time of forming the second semiconductor layer, an upper surface of such uppermost barrier layer is caused to disappear so that the thickness of the uppermost barrier layer becomes substantially equal to those of the other barrier layers.

Semiconductor light-emitting device

Electrodes for p-type group III nitride compound semiconductors

A light-emitting diode or laser diode is provided which uses a Group III nitride compound semiconductor satisfying the formula (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y N, inclusive of 0.ltoreq.x.ltoreq.1, and 0.ltoreq.y.ltoreq.1. A double hetero-junction structure is provided which sandwiches an active layer between layers having wider band gaps than the active layer. The diode has a multi-layer structure which has either a reflecting layer to reflect emission light or a reflection inhibiting layer. The emission light of the diode exits the diode in a direction perpendicular to the double hetero-junction structure. Light emitted in a direction opposite to the light outlet is reflected by the reflecting film toward the direction of the light outlet. Further, the reflection inhibiting film, disposed at or near the light outlet, helps the release of exiting light by minimizing or preventing reflection. As a result, light can be efficiently emitted by the light-generating diode.

Light-emitting semiconductor device using gallium nitride compound

A light-emitting semiconductor device having an improved metal electrode and semiconductor structure that lowers the driving voltage of the device. The device has a hetero p-n junction structure. This structure includes: (1) an n-layer having n-type conduction and a Group III nitride compound semiconductor satisfying the formula Al.sub.x Ga.sub.y In.sub.1-x-y N, inclusive of x=0, y=0, and x=y=0; (2) a p-layer having p-type conduction and a Group III nitride compound semiconductor satisfying the formula Al.sub.x Ga.sub.y In.sub.1-x-y N, inclusive of x=0, y=0, and x=y=0; and (3) an emission layer disposed between the n-layer and the p-layer. The device also has a metal electrode and a contact layer that is disposed between the p-layer and the metal electrode. The contact layer is doped with an acceptor impurity more heavily that is the p-layer. The acceptor impurity may be magnesium (Mg). The contact layer may be doped within the range of 1.times.10.sup.20 /cm.sup.3 to 1.times.10.sup.2l /cm.sup.3 and may comprise a first and a second contact layer.

Light-emitting semiconductor device using a Group III nitride compound

A light-emitting semiconductor device includes a sapphire substrate whose main surface orientation is tilted by 1 to 4 degrees from its axis 'a' &lt;1120&gt;, and layers epitaxially formed thereon. Tilting the surface orientation of the sapphire substrate enables uniform doping of a p-type impurity into the layers epitaxially grown thereon. As a result, the luminous intensity of the light-emitting semiconductor device is improved.

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Aichi, Japan

Junichi Umezaki