Kabushiki Kaisha Toshiba

Other

Toshiba Ceramics., Ltd.

Chie Hongo

Shinya Nunoue

Koichi Tachibana

Hajime Nago

Hiroshi Tomita

Masaaki Onomura

Tsuneo Ishii

Hideto Sugawara

Akira Tanaka

Yoshiyuki Harada

A semiconductor device has an active layer, a first semiconductor layer of first conductive type, an overflow prevention layer disposed between the active layer and the first semiconductor layer, which is doped with impurities of first conductive type and which prevents overflow of electrons or holes, a second semiconductor layer of first conductive type disposed at least one of between the active layer and the overflow prevention layer and between the overflow prevention layer and the first semiconductor layer, and an impurity diffusion prevention layer disposed between the first semiconductor layer and the active layer, which has a band gap smaller than those of the overflow prevention layer, the first semiconductor layer and the second semiconductor layer and which prevents diffusion of impurities of first conductive type.

Semiconductor device

A gallium nitride based semiconductor device comprises: a first gallium nitride based semiconductor film doped with magnesium; and a second gallium nitride based semiconductor film provided on the first gallium nitride based semiconductor film and doped with magnesium. The first gallium nitride based semiconductor film has substantially flat distributions of magnesium concentration and hydrogen atom concentration, and the magnesium concentration is higher than the hydrogen atom concentration. The second gallium nitride based semiconductor film has a first region in which the magnesium concentration decreases and the hydrogen atom concentration increases toward the surface, and the magnesium concentration in the first region is higher than the hydrogen atom concentration in the first region and higher than the magnesium concentration in the first gallium nitride based semiconductor film.

Gallium nitride based semiconductor device and method of manufacturing same

A semiconductor substrate encompasses a GaN substrate and a single-crystal layer formed of III-V nitride compound semiconductor epitaxially grown on the GaN substrate. The GaN substrate has a surface orientation defined by an absolute value of an off-angle of the surface from {0001} plane towards &#x3c;1-100&#x3e; direction lying in a range of 0.12 degree to 0.35 degree and by an absolute value of an off-angle of the surface from {0001} plane towards &#x3c;11-20&#x3e; direction lying in a range of 0.00 degree to 0.06 degree.

Method for manufacturing a semiconductor device on GAN substrate having surface bidirectionally inclined toward &#x3c;1-100&#x3e; and &#x3c;11-20&#x3e; directions relative to {0001} crystal planes

A semiconductor substrate encompasses a GaN substrate and a single-crystal layer formed of III-V nitride compound semiconductor epitaxially grown on the GaN substrate. The GaN substrate has a surface orientation defined by an absolute value of an off-angle of the surface from {0001} plane towards &#x3c;1&#x2212;100&#x3e; direction lying in a range of 0.12 degree to 0.35 degree and by an absolute value of an off-angle of the surface from {0001} plane towards &#x3c;11&#x2212;20&#x3e; direction lying in a range of 0.00 degree to 0.06 degree.

Semiconductor device having bidirectionally inclined toward &#x3c;1-100&#x3e; and &#x3c;11-20&#x3e; relative to {0001} crystal planes

A semiconductor laser device comprising: a first cladding layer of a first conductivity type; an active layer provided on the first cladding layer and having a quantum well structure; an overflow blocking layer of a second conductivity type provided on the overflow blocking layer. The active layer includes a region having an impurity concentration is 3&#xd7;10cmor more and having a thickness of 30 nm or less between the overflow blocking layer and a well layer in the active layer closet to the overflow blocking layer.

Semiconductor laser device

A quartz glass which would not become a source for the contamination even if it contains metallic impurities. This quartz glass includes a region where a concentration of E&prime; center as measured by means of an. electron spin resonance analysis is 3&times;10 cm or more. This quartz glass can be manufactured by a method including the steps of forming an initial quartz glass by melting and quenching a raw material for quartz glass, and implanting therein an ion, which is capable of entering into an SiO network of the initial quartz glass and substantially incapable of externally diffusing, to increase a concentration of E&prime; center in at least part of the initial quartz glass. This quartz glass can be manufactured by a method making use of a quartz glass raw material containing 0.01 to 0.1% by weight of-silicon, by a method of irradiating ultraviolet ray to the initial quartz glass, or by a method of giving an abrasion damage to the surface of the initial quartz glass by means of sand blast.

Heat treating apparatus using quartz glass

A quartz glass which would not become a source for the contamination even if it contains metallic impurities. This quartz glass includes a region where a concentration of E&prime; center as measured by means of an electron spin resonance analysis is 3&times;10,cm,or more. This quartz glass can be manufactured by a method including the steps of forming an initial quartz glass by melting and quenching a raw material for quartz glass, and implanting therein an ion, which is capable of entering into an SiO,network of the initial quartz glass and substantially incapable of externally diffusing, to increase a concentration of E&prime; center in at least part of the initial quartz glass. This quartz glass can be manufactured by a method making use of a quartz glass raw material containing 0.01 to 0.1% by weight of silicon, by a method of irradiating ultraviolet ray to the initial quartz glass, or by a method of giving an abrasion damage to the surface of the initial quartz glass by means of sand blast.

Quartz glass, heat treating apparatus using quartz glass, and heat treating method

A quartz glass which would not become a source for the contamination even if it contains metallic impurities. This quartz glass includes a region where a concentration of E' center as measured by means of an electron spin resonance analysis is 3.times.10.sup.19 cm.sup.-3 or more. This quartz glass can be manufactured by a method including the steps of forming an initial quartz glass by melting and quenching a raw material for quartz glass, and implanting therein an ion, which is capable of entering into an SiO.sub.2 network of the initial quartz glass and substantially incapable of externally diffusing, to increase a concentration of E' center in at least part of the initial quartz glass. This quartz glass can be manufactured by a method making use of a quartz glass raw material containing 0.01 to 0.1% by weight of silicon, by a method of irradiating ultraviolet ray to the initial quartz glass, or by a method of giving an abrasion damage to the surface of the initial quartz glass by means of sand blast.

Growing community of inventors

Yokohama, Japan

Chie Hongo