Ricoh Company, Ltd.

Osaka University

Japan Atomic Energy Agency

Ricoh Research Institute of General Electronics

Hirokazu Iwata

Hisanori Yamane

Masahiko Shimada

Akihiro Fuse

Masafumi Kumano

Akira Takahashi

Minoru Fukuda

Hiroaki Ikeda

Shunichi Sato

Yasuo Kitaoka

Tatsuya Miyadera

Takashi Takahashi

Yusuke Mori

Seiji Sarayama

Masato Aoki

Takashi Araki

Tetsuya Takahashi

Junichi Saito

Morimasa Kaminishi

Izumi Kinoshita

Takeshi Kawashima

Yasuo Matsuyama

Tatsuya Ozaki

Kenji Asuwa

Kuniaki Ara

Hiroyuki Iechi

Takashi Satoh

Takaaki Miyashita

Hiroshi Nambu

Chizuru Yoshida, Legal Representative

Tomoaki Yoshida, Deceased

Shunichi Satoh

A reflector includes a low refractive index layer and a high refractive index layer. The low refractive index layer has a first average refractive index and has a laminated structure in which an AlN layer and a GaN layer are alternately laminated. The high refractive index layer has a second average refractive index higher than the first average refractive index and includes an InGaN layer.

Reflector, surface emitting laser, method for manufacturing reflector, and method for manufacturing surface emitting laser

A crystal has a diameter of 1 cm or more and shows a strongest peak in cathode luminescent spectrum at a wavelength of 360 nm in correspondence to a band edge.

Production of a GaN bulk crystal substrate and a semiconductor device formed on a GaN bulk crystal substrate

A crystal growth apparatus comprises a reaction vessel holding a melt mixture containing an alkali metal and a group III metal, a gas supplying apparatus supplying a nitrogen source gas to a vessel space exposed to the melt mixture inside the reaction vessel, a heating unit heating the melt mixture to a crystal growth temperature, and a support unit supporting a seed crystal of a group III nitride crystal inside the melt mixture.

Crystal growth apparatus and manufacturing method of group III nitride crystal

A method of producing an n-type group III nitride single crystal includes putting raw materials that include at least a substance including a group III element, an alkali metal, and boron oxide into a reaction vessel; melting the boron oxide by heating the reaction vessel to a melting point of the boron oxide; forming a mixed melt which includes the group III element, the alkali metal, and the boron oxide, in the reaction vessel by heating the reaction vessel to a crystal growth temperature of a group III nitride; dissolving nitrogen into the mixed melt by bringing a nitrogen-containing gas into contact with the mixed melt; and growing an n-type group III nitride single crystal, which is doped with oxygen as a donor, from the group III element, the nitrogen, and oxygen in the boron oxide that are dissolved in the mixed melt.

Method for producing N-type group III nitride single crystal, N-type group III nitride single crystal, and crystal substrate

A method for manufacturing a group III nitride crystal on a seed crystal in a holding vessel holding therein a melt containing a group III metal, an alkali metal and nitrogen. The manufacturing method comprises the steps of causing the seed crystal to make a contact with the melt, setting an environment of the seed crystal to a first state offset from a crystal growth condition while in a state in which said seed crystal is in contact with the melt, increasing a nitrogen concentration in the melt, and setting the environment of the seed crystal to a second state suitable for crystal growth when the nitrogen concentration of the melt has reached a concentration suitable for growing the seed crystal.

Manufacturing method and manufacturing apparatus of a group III nitride crystal, utilizing a melt containing a group III metal, an alkali metal, and nitrogen

A group III nitride crystal containing therein an alkali metal element comprises a base body, a first group III nitride crystal formed such that at least a part thereof makes a contact with the base body, the first group III nitride crystal deflecting threading dislocations in a direction different from a direction of crystal growth from the base body and a second nitride crystal formed adjacent to the first group III nitride crystal, the second nitride crystal having a crystal growth surface generally perpendicular to the direction of the crystal growth.

Group III nitride crystal and manufacturing method thereof

A crystal manufacturing apparatus for manufacturing a group III nitride crystal includes a crucible that holds a mixed molten liquid including an alkali metal and a group III metal; a reaction vessel accommodating the crucible in the reaction vessel; a heating device that heats the crucible with the reaction vessel; a holding vessel having a lid that is capable of opening and closing, accommodating the reaction vessel and the heating device in the holding vessel; a sealed vessel accommodating the holding vessel in the sealed vessel, having an operating device that enables opening the lid of the holding vessel for supplying source materials into the crucible and taking out a manufactured GaN crystal under a sealed condition, and closing the lid of the holding vessel that is sealed in the sealed vessel, the sealed vessel including an inert gas atmosphere or a nitrogen atmosphere; and a gas supplying device for supplying a nitrogen gas to the mixed molten liquid through each of the vessels.

Crystal manufacturing apparatus

A nitride crystal which encircles an outer periphery of a seed crystal, the nitride crystal in an embodiment includes: a first partial region, and a second partial region that has optical characteristics different from those of the first partial region and has optical characteristics which indicate the crystal orientation.

Nitride crystal and method for producing the same

In a method of producing a group III nitride crystal in which a melt holding vessel where a melt containing a group III metal and flux is held is accommodated in a reaction vessel and a group III nitride crystal is produced as a substance containing nitrogen is supplied from an outside to the reaction vessel through a pipe, the method includes a step of forming an accumulated part of a liquid in the pipe to thereby temporarily close the pipe before growing the group III nitride crystal in the melt holding vessel.

Method of producing group III nitride crystal, apparatus for producing group III nitride crystal, and group III nitride crystal

A crystal producing apparatus includes a crystal forming unit and a crystal growing unit. The crystal forming unit forms a first gallium nitride (GaN) crystal by supplying nitride gas into melt mixture containing metal sodium (Na) and metal gallium (Ga). The first GaN crystal is sliced and polished to form GaN wafers. The crystal growing unit grows a second GaN crystal on a substrate formed by using a GaN wafer, by the hydride vapor phase epitaxy method, thus producing a bulked GaN crystal.

Crystal producing apparatus, crystal producing method, substrate producing method, gallium nitride crystal, and gallium nitride substrate

A group-III nitride crystal growth method comprises the steps of: a) preparing a mixed molten liquid of an alkaline material and a substance at least containing a group-III metal; b) causing growth of a group-III nitride crystal from the mixed molten liquid prepared in the step a) and a substance at least containing nitrogen; and c) creating a state in which nitrogen can be introduced into the molten liquid prepared by the step a).

Crystal growth apparatus

A method is provided for producing a single crystal body of a group III nitride, comprising the steps of forming a molten flux of a volatile metal in a reaction vessel and causing a growth of a GaN single crystal from the molten flux, wherein the growth is continued while replenishing a compound containing N from a source outside the reaction vessel, and wherein a seed crystal is disposed in the reaction vessel.

Production of a GaN bulk crystal substrate and a semiconductor device formed thereon

In a crystal preparing device, a crucible holds a mixed molten metal containing alkali metal and group III metal. A container has a container space contacting the mixed molten metal and holds a molten alkali metal between the container space and an outside of the container, the molten alkali metal contacting the container space. A gas supply device supplies nitrogen gas to the container space. A heating device heats the crucible to a crystal growth temperature. The crystal preparing device is provided so that a vapor pressure of the alkali metal which evaporates from the molten alkali metal is substantially equal to a vapor pressure of the alkali metal which evaporates from the mixed molten metal.

Growing community of inventors

Miyagi, Japan

Hirokazu Iwata