Mitsubishi Cable Industries, Ltd.

Mitsubishi Chemical Corporation

Yoichiro Ouchi

Hiroaki Okagawa

Kazuyuki Tadatomo

Masahiro Koto

Takashi Tsunekawa

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.

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Itami, Japan

Yoichiro Ouchi