Sumitomo Chemical Company, Limited

Hitachi Metals, Ltd.

Kabushiki Kaisha Topcon

Sciocs Company Limited

Naoki Kaneda

Tomoyoshi Mishima

Tadayoshi Tsuchiya

Tomonobu Tsuchiya

Takeshi Tanaka

Akihisa Terano

Yoshinobu Narita

Tohru Nakamura

Kazuhiro Mochizuki

Shigeki Yagioka

Hiroshi Nawata

A nitride semiconductor epitaxial wafer includes a substrate, a GaN layer provided over the substrate, and an AlGaN layer provided over the GaN layer. The GaN layer has a wurtzite crystal structure, and a ratio c/a of a lattice constant c in a c-axis orientation of the GaN layer to a lattice constant a in an a-axis orientation of the GaN layer is not more than 1.6266.

Nitride semiconductor epitaxial wafer and field effect nitride transistor

There is provided a semiconductor multilayer structure, including:

Semiconductor multilayer structure and method of manufacturing the same

Disclosed are an npn-type bipolar transistor as a nitride semiconductor device having good characteristics, and a method of manufacturing the same. A so-called pn epitaxial substrate has a structure wherein an n-type collector layer and a p-type base layer of a three-layer structure are provided over a substrate. The three-layer structure includes first (lower layer side), second, and third (upper layer side) p-type base layers which differ in thickness and p-type impurity concentration. In a partial region inside the second p-type base layer located as an intermediate layer in the p-type base layer of the three-layer structure, an n-type emitter region is formed by ion implantation.

Nitride semiconductor device and method of manufacturing the same

A high voltage gallium nitride based semiconductor device includes an n-type gallium nitride freestanding substrate, and an n-type gallium nitride based semiconductor layer including a drift layer formed on the surface of the n-type gallium nitride freestanding substrate so as to have a reverse breakdown voltage of not less than 3000 V. The drift layer is configured such that a carbon concentration is not less than 3.0&#xd7;10/cmin a region which has an electric field intensity of not more than 1.5 MV/cm when a maximum allowable voltage where there occurs no breakdown phenomenon is applied as a reverse bias voltage.

High voltage gallium nitride based semiconductor device and manufacturing method of the same

A nitride semiconductor element having a high reverse breakdown voltage and a method of manufacturing the same are provided. A diode (a vertical-type SBD) has an n-type nitride semiconductor layer (a drift region) formed on an n-type nitride semiconductor substrate, a p-type nitride semiconductor layer formed on the n-type nitride semiconductor layer, and besides, an anode electrode formed on the p-type nitride semiconductor layer. The p-type nitride semiconductor layer has a relatively-thin first portion and a relatively-thick second portion provided so as to surround the first portion as being in contact with an outer circumference of the first portion. Also, the relatively-thin first portion of the p-type nitride semiconductor layer is formed thinner than the second portion so as to be depleted. The relatively-thick second portion of the p-type nitride semiconductor layer forms a guard ring part.

Nitride semiconductor element and method of manufacturing the same

There is provided a group III nitride semiconductor crystal, containing a donor-type impurity and having a hydrogen concentration of 2.0E+16 cmor less in a crystal.

Group III nitride semiconductor crystal, group III nitride semiconductor substrate, group III nitride semiconductor freestanding substrate, nitride semiconductor device, and rectifier diode

A gallium nitride rectifying device includes a p-type gallium nitride based semiconductor layer and an n-type gallium nitride based semiconductor layer, the two layers forming a pn junction with each other. The p-type gallium nitride based semiconductor layer has a carrier trap (level) density of not more than 1&#xd7;10cm, or the n-type gallium nitride based semiconductor layer has a carrier trap (level) density of not more than 1&#xd7;10cm.

Gallium nitride rectifying device

An ophthalmologic imaging system comprises: a retinal camera having an illuminating optical system configured to project an illuminating light onto fundus oculi of a subject and an imaging optical system including an imaging part configured to receive the fundus reflection light of the illuminating light and output an imaging signal; and a computer having a package separate from the retinal camera, communicably connected to the retinal camera, and having a display configured to display a fundus oculi image based on the imaging signal, wherein: the retinal camera comprises an operation part; and the computer comprises a controller configured to instruct the display to display information based on an operation signal transmitted from the retinal camera in response to an operation by the operation part.

Growing community of inventors

Tsuchiura, Japan

Naoki Kaneda