Toyoda Gosei Co., Ltd.

Koha Co., Ltd.

Yasuhisa Ushida

Koji Okuno

Naoyuki Nakada

Yoshiki Saito

Shinya Boyama

Naoki Shibata

Kazuo Aoki

Kiyoshi Shimamura

Encarnacion Antonia Garcia Villora

Masao Kamiya

Koji Hirata

Shugo Nitta

Daisuke Shinoda

Yuhei Ikemoto

Masato Aoki

Daisuke Yamazaki

A semiconductor substrate includes a sapphire substrate including a c-plane main surface and a groove in a surface thereof, the groove including side surfaces and a bottom surface, and a Group III nitride semiconductor layer formed on the sapphire substrate. The side surfaces of the groove are an a-plane of sapphire. An axis of the Group III nitride semiconductor layer, perpendicular to one of the side surface of the groove, is a c-axis of Group III nitride semiconductor. A plane of the Group III nitride semiconductor, parallel to the main surface of the sapphire substrate, is an a-plane of Group III nitride semiconductor.

Method for producing group III nitride semiconductor and template substrate

A semiconductor substrate includes a sapphire substrate including an a-plane main surface and a groove in a surface thereof, the groove includes side surfaces and a bottom surface, and a Group III nitride semiconductor layer formed on the sapphire substrate. Both side surfaces of the groove assume a c-plane of sapphire. An axis perpendicular to one of the side surfaces of the groove of the Group III nitride semiconductor layer assumes a c-axis of Group III nitride semiconductor. A plane parallel to the main surface of the sapphire substrate of the Group III nitride semiconductor layer assumes an m-plane of Group III nitride semiconductor.

The present invention is a method for producing a light-emitting device whose p contact layer has a p-type conduction and a reduced contact resistance with an electrode. On a p cladding layer, by MOCVD, a first p contact layer of GaN doped with Mg is formed. Subsequently, after lowering the temperature to a growth temperature of a second p contact layer being formed in the subsequent process, which is 700&#xb0; C., the supply of ammonia is stopped and the carrier gas is switched from hydrogen to nitrogen. Thereby, Mg is activated in the first p contact layer, and the first p contact layer has a p-type conduction. Next, the second p contact layer of InGaN doped with Mg is formed on the first p contact layer by MOCVD using nitrogen as a carrier gas while maintaining the temperature at 700&#xb0; C. which is the temperature of the previous process.

Method for producing a group III nitride semiconductor light-emitting device

The present invention provides a Group III nitride semiconductor light-emitting device exhibiting improved light extraction performance. In the production method, a p cladding layer of p-AlGaN is formed by the MOCVD method on a light-emitting layer at a pressure of 30 kPa and with an Mg concentration of 1.5&#xd7;10/cm. A plurality of regions with a nitrogen polarity is formed in the crystals with a Group III element polarity, and thus the p cladding layer has a hexagonal columnar concave and convex configuration on the surface thereof. Subsequently, a p contact layer of GaN is formed by the MOCVD method, in a film along the concave and convex configuration on the p cladding layer.

A group III nitride compound semiconductor light emitting device that inhibits occurrence of dislocation in a strain relaxation layer in forming a group III nitride compound semiconductor layer on a thin GaN substrate, and a method for producing the same are provided. A light emitting devicecomprises a support substrate, a GaN substrate, an n-type contact layer, a strain relaxation layer(n-type InGaN layer), a light emitting layer, a p-type clad layer, and a p-type contact layer. The GaN substratehas a thickness in a range of from 10 nm to 10 &#x3bc;m. The strain relaxation layer(n-type InGaN layer) has an In composition ratio X in a range of from larger than 0 to 3%.

Group III nitride compound semiconductor light emitting element and method for producing the same

The present invention provides a method for producing a Group III nitride semiconductor. The method includes forming a groove in a surface of a growth substrate through etching; forming a buffer film on the groove-formed surface of the growth substrate through sputtering; heating, in an atmosphere containing hydrogen and ammonia, the substrate to a temperature at which a Group III nitride semiconductor of interest is grown; and epitaxially growing the Group III nitride semiconductor on side surfaces of the groove at the growth temperature. The thickness of the buffer film or the growth temperature is regulated so that the Group III nitride semiconductor is grown primarily on the side surfaces of the groove in a direction parallel to the main surface of the growth substrate. The thickness of the buffer film is regulated to be smaller than that of a buffer film which is employed for epitaxially growing the Group III nitride semiconductor on a planar growth substrate uniformly in a direction perpendicular to the growth substrate. The growth temperature is regulated to be lower than a temperature at which the Group III nitride semiconductor is epitaxially grown on a planar growth substrate uniformly in a direction perpendicular to the growth substrate. The growth temperature is preferably 1,020 to 1,100&#xb0; C. The buffer film employed is an AlN film having a thickness of 150 &#x212b; or less.

The present invention provides a Group III nitride semiconductor light-emitting device whose main surface is a plane which provides an internal electric field of zero, and which exhibits improved emission performance. The light-emitting device includes a sapphire substrate which has, in a surface thereof, a plurality of dents which are arranged in a stripe pattern as viewed from above; an n-contact layer formed on the dented surface of the sapphire substrate; a light-emitting layer formed on the n-contact layer; an electron blocking layer formed on the light-emitting layer; a p-contact layer formed on the electron blocking layer; a p-electrode; and an n-electrode. The electron blocking layer has a thickness of 2 to 8 nm and is formed of Mg-doped AlGaN having an Al compositional proportion of 20 to 30%.

Group III nitride semiconductor light-emitting device

A light-emitting element includes a semiconductor laminated structure including a nitride semiconductor, and formed by laminating a first semiconductor layer of a first conductivity type, a light-emitting layer and a second semiconductor layer of a second conductivity type different from the first conductivity type, the first semiconductor layer being exposed by removing a part of the second semiconductor layer and the light-emitting layer, a concave portion formed in the exposed portion of the first semiconductor layer, a first electrode formed on the concave portion and being in ohmic contact with the first semiconductor layer, and a second electrode being in ohmic contact with the second semiconductor layer and formed surrounding the first electrode.

Light-emitting element

To produce a Group III nitride-based compound semiconductor having a m-plane main surface and uniformly oriented crystal axes. A mesa having a side surface having an off-angle of 45&#xb0; or less from c-plane is formed in a a-plane main surface of a sapphire substrate. Subsequently, trimethylaluminum is supplied at 300&#xb0; C. to 420&#xb0; C., to thereby form an aluminum layer having a thickness of 40 &#x212b; or less. The aluminum layer is nitridated to form an aluminum nitride layer. Through the procedure, a Group III nitride-based compound semiconductor is epitaxially grown only from a side surface of the mesa having an off-angle of 45&#xb0; or less from c-plane in the sapphire substrate having an a-plane main surface. Thus, a Group III nitride-based compound semiconductor having m-plane which is parallel to the main surface of the sapphire substrate can be formed.

Method for producing group III nitride-based compound semiconductor, wafer including group III nitride-based compound semiconductor, and group III nitrided-based compound semiconductor device

A characteristic feature of the invention is to form, in a Group III nitride-based compound semiconductor device, a negative electrode on a surface other than a Ga-polar C-plane. In a Group III nitride-based compound semiconductor light-emitting device, there are formed, on an R-plane sapphire substrate, an n-contact layer, a layer for improving static breakdown voltage, an n-cladding layer made of a multi-layer structure having ten stacked sets of an undoped InGaN layer, an undoped GaN layer, and a silicon (Si)-doped GaN layer, a multi-quantum well (MQW) light-emitting layer made of a combination of InGaN well layers and GaN barrier layers stacked alternatingly, a p-cladding layer made of a multi-layer structure including a p-type AlGaN layer and a p-InGaN layer, and a p-contact layer (thickness: about 80 nm) made of a stacked structure including two p-GaN layers having different magnesium concentrations. Through etching, the n-contact layer having a thickness direction along the c-axis is provided with stripe-patterned microditches each having side walls, which assume a C-plane, whereby ohmic contact is established between a negative electrode and each C-plane side wall.

Group III nitride-based compound semiconductor device

A method of forming a low temperature-grown buffer layer having the steps of: placing a GaOsubstrate in a MOCVD apparatus; providing a Hatmosphere in the MOCVD apparatus and setting a buffer layer growth condition having an atmosphere temperature of 350&#xb0; C. to 550&#xb0; C.; and supplying a source gas having two or more of TMG, TMA and NHonto the GaOsubstrate in the buffer layer growth condition to form the low temperature-grown buffer layer on the GaOsubstrate.

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Kiyosu, Japan

Yasuhisa Ushida