Fuji Electric Co., Ltd.

Koa Corporation

Jfe Mineral Company, Ltd.

Octec, Inc.

Kyushu University

National Institute of Technology

Koa Corporoation

Kenichi Iguchi

Haruo Nakazawa

Koh Yoshikawa

Masaaki Ogino

Tsunehiro Nakajima

Yasukazu Seki

Masaaki Tachioka

Katsuya Okumura

Hiroki Wakimoto

Yoji Gomi

Etsurou Udagawa

Yuko Echizenya

Yoshimi Nakata

Chika Ito

Shunsuke Tanaka

Ken Takahashi

Tetsuro Tanaka

Naoto Fujishima

Motoyoshi Kubouchi

Kiyokazu Nakagawa

Kosuke Yoshida

Hiroshi Ikenoue

Koichi Urano

Akihiro Ikeda

Tanemasa Asano

Hisakazu Nagata

Naomi Ishida

Yusuke Wada

Yukiko Ota

Kenji Obata

Shigenori Matsushima

A sensor element () has a cross-sectional area that continuously only increases from a positive (+) electrode side toward a negative (−) electrode side, thereby leading a hot spot, which attempts to move to the negative electrode side, to a lower resistance side. A position that is at nearly equal distances from paired electrodes (and) formed on either end of the sensor element () is set as a hot spot generating position, so as to avoid damage to the electrodes due to heat emitted by the hot spot.

Gas sensor

The gas sensor is provided with: a base material; a first electrode and a second electrode arranged on the base material; and a gas detection member connected to the first electrode and the second electrode, wherein the gas detection member contains flaky particles of alkaline earth ferrite.

Gas sensor and method for producing alkaline earth ferrite

An oxygen sensor for detecting gas concentration based on either an electric current value or a resistance value measured when a voltage is applied to a sensor element includes gaps formed between electrodes arranged in an element main body and ridges where surfaces of an element touch each other. These gaps will be escaping parts for expansion and contraction of electrode material that accompany thermal expansion and contraction of a sensor main body, and concentration of thermal stress at edge parts of the element main body may thus be eliminated, thereby alleviating thermal stress on the oxygen sensor. This allows provision of a gas sensor that controls generation of cracks in the element and that is stably usable over a long period of time.

Gas sensor and method for manufacturing same

Focusing on zinc oxide itself, which is a main raw material for a zinc oxide varistor (laminated varistor), a predetermined amount of additive is added to a zinc oxide powder having crystallite size of 20 to 100 nm, particle diameter of 20 to 110 nm found using a specific area BET method, untamped density of 0.60 g/cmor greater, and tap density of 0.80 g/cmor greater. This allows a zinc oxide sintered body to secure uniformity, high density, and high electric conductivity, resulting in a zinc oxide varistor with high surge resistance, capable of downsizing and cost reduction. Moreover, addition of aluminum (Al), as a donor element, to the zinc oxide powder allows control of sintered grain size in conformity with the aluminum added amount and baking temperature, and also allows adjustment of varistor voltage, etc.

Zinc oxide varistor

Focus is on zinc oxide itself, which is a base material for a zinc oxide varistor (laminated varistor), wherein specified quantities of additives are added to a zinc oxide powder having a crystallite size of 20 to 50 nm, grain diameter of 15 to 60 nm found using the specific surface area BET method, untamped density of 0.38 to 0.50 g/cm, and tap density of 0.50 to 1.00 g/cm. This allows securing of uniformity, high compactness, and high electrical conductivity of a zinc oxide sintered body, and provision of a zinc oxide varistor having high surge resistance.

Zinc oxide varistor and method for manufacturing same

A semiconductor device is manufactured by implanting impurity ions in one surface of a semiconductor substrate made of silicon carbide; irradiating a region of the semiconductor substrate implanted with the impurity ions with laser light of a wavelength in the ultraviolet region; and forming, on a surface of a high-concentration impurity layer formed by irradiating with the laser light, an electrode made of metal in ohmic contact with the high-concentration impurity layer. When irradiating with the laser light, a first concentration peak of the impurity ions that exceeds a solubility limit concentration of the impurity ions in silicon carbide is formed in a surface region near the one surface of the semiconductor substrate within the high-concentration impurity layer.

Semiconductor device and method of manufacturing semiconductor device

A semiconductor device having a semiconductor substrate that includes a first-conductivity-type substrate and a first-conductivity-type epitaxial layer, and a plurality of trenches reaching a predetermined depth from a main surface of the semiconductor substrate to terminate in the first-conductivity-type epitaxial layer. The semiconductor substrate includes a hydrogen-donor introduced part, of which a concentration of a hydrogen donor is greatest at a depth position that is separate from bottoms of the trenches by a distance at least two times of the depth of the trenches. The impurity concentration of an impurity dopant of the first-conductivity-type substrate being lower than that of the first-conductivity-type epitaxial layer. A difference between a first resistivity, corresponding to a total impurity concentration of the impurity dopant and the hydrogen donor of the first-conductivity-type substrate, and a second resistivity, corresponding to the impurity concentration of the impurity dopant of the first-conductivity-type epitaxial layer, is at most 20%.

A silicon carbide semiconductor device includes a first semiconductor layer of silicon carbide, a device structure provided on top of the first semiconductor layer, a second semiconductor layer of silicon carbide having a higher impurity concentration than the first semiconductor layer, provided under the first semiconductor layer, the second semiconductor layer implementing an ohmic-contact, and a metallic electrode film provided under the second semiconductor layer. A thickness of a carbon-containing region in which carbon-atoms are precipitated between the second semiconductor layer and the metallic electrode film is 10 nm or less.

Silicon carbide semiconductor device and method for manufacturing the same

A doping system includes a light source to emit an optical pulse; a light source controller connected to the light source, to control an energy density of the optical pulse; and a beam adjusting unit to irradiate the optical pulse to a surface of a doping-object made of silicon carbide on which an impurity-containing source-film containing impurity atoms is deposited. The light source controller irradiates a first optical pulse to the impurity-containing source-film so as to form a reaction-product layer in the doping-object, and irradiates a second optical pulse having an energy density higher than an energy density of the first optical pulse, so as to introduce the impurity atoms into the target through the reaction-product layer.

Doping system, doping method and method for manufacturing silicon carbide semiconductor device

An impurity-doping apparatus is provided with: a supporting plate which supports a semiconductor substrate; a wall-like block disposed above the supporting plate floating away from the semiconductor substrate, the wall-like block implements a recess inside so as to establish a space for a solution region containing impurity elements, the solution region is localized on an upper surface of the semiconductor substrate, the upper surface being opposite to an bottom surface facing to the supporting plate; and a laser optical system, configured to irradiate a laser beam onto the upper surface of the semiconductor substrate, through the solution region surrounded by the wall-like block, wherein the impurity elements are doped into a part of the semiconductor substrate by irradiation of the laser beam.

Impurity adding apparatus, impurity adding method, and semiconductor element manufacturing method

A method of manufacturing a semiconductor device includes assigning a plurality of chip regions on an epitaxial-growth layer of a semiconductor substrate where the epitaxial-growth layer is grown on a bulk layer and forming a plurality of device structures on the plurality of chip regions, respectively, thinning the semiconductor substrate from a bottom-surface side of the bulk layer, bonding a supporting-substrate on a bottom surface of the thinned semiconductor substrate, selectively removing the supporting-substrate so that the bottom surface of the semiconductor substrate is exposed, at locations corresponding to positions of each of main current paths in the plurality of device structures, respectively, dicing the semiconductor substrate together with the supporting-substrate along dicing lanes between the plurality of the chip regions so as to form a plurality of chips.

Method of manufacturing semiconductor device by removing a bulk layer to expose an epitaxial-growth layer and by removing portions of a supporting-substrate to expose portions of the epitaxial-growth layer

A method of manufacturing a semiconductor device includes: forming, on a surface of an n-type semiconductor layer, an impurity source film containing both aluminum and beryllium; and forming a p-type impurity-doped layer in the n-type semiconductor layer by irradiating the impurity source film with first laser light to simultaneously introduce the aluminum and the beryllium into the n-type semiconductor layer.

Method of manufacturing semiconductor device

A semiconductor device having a voltage resistant structure in a first aspect of the present invention is provided, comprising a semiconductor substrate, a semiconductor layer on the semiconductor substrate, a front surface electrode above the semiconductor layer, a rear surface electrode below the semiconductor substrate, an extension section provided to a side surface of the semiconductor substrate, and a resistance section electrically connected to the front surface electrode and the rear surface electrode. The extension section may have a lower permittivity than the semiconductor substrate. The resistance section may be provided to at least one of the upper surface and the side surface of the extension section.

Manufacturing method of semiconductor device having a voltage resistant structure

A method of manufacturing a semiconductor device includes providing a semiconductor substrate having a front surface and a back surface; forming a transition metal layer on a surface of the semiconductor substrate; and exposing the semiconductor substrate having the transition metal layer formed thereon to a hydrogen plasma atmosphere formed by microwaves, to cause the transition metal layer to generate heat. During exposure of the semiconductor substrate, a portion of the semiconductor substrate contacting the transition metal layer is heated by a transfer of heat from the transition metal layer and, at an interface of the transition metal layer and the semiconductor substrate, an ohmic contact is formed by reaction of the transition metal layer and the semiconductor substrate, such as to form a transition metal silicide when the semiconductor substrate is silicon carbide. The ohmic contact provides a lower contact resistivity and device properties can be prevented from degrading.

Method for forming metal-semiconductor alloy using hydrogen plasma

A first nickel film is deposited inside a contact hole of an interlayer dielectric formed on an n-type SiC substrate. Irradiation with a first laser is carried out, forming an Ohmic contact with a silicon carbide semiconductor. A second nickel film and a front surface electrode film are deposited on the first nickel film, forming a source electrode. The back surface of the n-type SiC substrate is ground, and a third nickel film is formed on the ground back surface of the n-type SiC substrate. Irradiation with a second laser is carried out, forming an Ohmic contact with the silicon carbide semiconductor. A fourth nickel film and a back surface electrode film are deposited on the third nickel film, forming a drain electrode. By so doing, it is possible to prevent electrical characteristic deterioration of a semiconductor device, and to prevent warping and cracking of a wafer.

Growing community of inventors

Matsumoto, Japan

Kenichi Iguchi