Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Denso Corpora Tion

Masaki Konishi

Hirokazu Fujiwara

Yukihiko Watanabe

Takeo Yamamoto

Takeshi Endo

Takashi Katsuno

Eiichi Okuno

Narumasa Soejima

Sachiko Aoi

Akitaka Soeno

Naohiro Suzuki

Shinichiro Miyahara

Tsuyoshi Ishikawa

Jun Morimoto

Jun Kawai

Tomoo Morino

Yukihiko Watanbe

A silicon carbide semiconductor device includes: a substrate; a drift layer; a current dispersion layer; a base region; a source region; trenches; a gate insulation film; a gate electrode; a source electrode; a drain electrode; and a bottom layer. The current dispersion layer is arranged on the drift layer, and has a first conductive type with an impurity concentration higher than the drift layer. The bottom layer has a second conductive type, is arranged under the base region, covers a bottom of each trench including a corner portion of the bottom of the trench, and has a depth equal to or deeper than the current dispersion layer.

Silicon carbide semiconductor device

A method of manufacturing a semiconductor device includes forming a drift layer on a substrate; forming a base layer on the drift layer; forming a trench to penetrate the base layer and to reach the drift layer; rounding off a part of a shoulder corner and a part of a bottom corner of the trench; covering an inner wall of the trench with an organic film; implanting an impurity to a surface portion of the base layer; forming a source region by activating the implanted impurity; and removing the organic film after the source region is formed, in which the substrate, the drift layer, the base layer and the source region are made of silicon carbide, and the implanting and the activating of the impurity are performed under a condition that the trench is covered with the organic film.

Method of manufacturing silicon carbide semiconductor device

A method for manufacturing a semiconductor device including a semiconductor substrate composed of silicon carbide, an upper surface electrode which contacts an upper surface of the substrate, and a lower surface electrode which contacts a lower surface of the substrate, the method including steps of: (a) forming an upper surface structure on the upper surface side of the substrate, and (b) forming a lower surface structure on the lower surface side of the substrate. The step (a) comprises steps of: (a1) depositing an upper surface electrode material layer on the upper surface of the substrate, the upper surface electrode material layer being a raw material layer of the upper surface electrode, and (a2) annealing the upper surface electrode material layer. The step (b) comprises steps of: (b1) depositing a lower surface electrode material layer on the lower surface of the substrate, the lower surface electrode material layer being a raw material layer of the lower surface electrode, and (b2) annealing the lower surface electrode material layer with a laser to make an ohmic contact between the lower surface electrode and the substrate.

Semiconductor device manufacturing method

A silicon carbide semiconductor device with a Schottky barrier diode includes a first conductivity type silicon carbide substrate, a first conductivity type silicon carbide drift layer on a first surface of the substrate, a Schottky electrode forming a Schottky contact with the drift layer, and an ohmic electrode on a second surface of the substrate. The Schottky electrode includes an oxide layer in direct contact with the drift layer. The oxide layer is made of an oxide of molybdenum, titanium, nickel, or an alloy of at least two of these elements.

Silicon carbide semiconductor device with Schottky barrier diode and method of manufacturing the same

A method of making a semiconductor device includes forming a p-type semiconductor region to an n-type semiconductor substrate in such a manner that the p-type semiconductor region is partially exposed to a top surface of the semiconductor substrate, forming a Schottky electrode of a first material in such a manner that the Schottky electrode is in Schottky contact with an n-type semiconductor region exposed to the top surface of the semiconductor substrate, and forming an ohmic electrode of a second material different from the first material in such a manner that the ohmic electrode is in ohmic contact with the exposed p-type semiconductor region. The Schottky electrode is formed earlier than the ohmic electrode.

Semiconductor device making method

First, a first layer made of Ni or an alloy including Ni may be formed on an upper surface of a semiconductor layer. Next, a second layer made of silicon oxide may be formed on an upper surface of the first layer. Next, a part, which corresponds to a semiconductor region, of the second layer may be removed. Next, second conductive type ion impurities may be injected from upper sides of the first and second layers to the semiconductor layer after the removing step.

Forming impurity regions in silicon carbide devices

A semiconductor device is provided in which the contact resistance of the interface between an electrode and the semiconductor substrate is reduced. The semiconductor device includes a 4H polytype SiC substrate, and an electrode formed on a surface of the substrate. A 3C polytype layer, which extends obliquely relative to the surface of the substrate and whose end portion at the substrate surface is in contact with the electrode, is formed at the surface of the substrate. The 3C polytype layer has a lower bandgap than 4H polytype. Hence, electrons present in the 4H polytype region pass through the 3C polytype layer and reach the electrode. More precisely, the width of the passageway of the electrons is determined by the thickness of the 3C polytype layer. Consequently, with this semiconductor device, in which the passageway of the electrons is narrow, the electrons are able to reach the electrode at a speed close to the theoretical value, by the quantum wire effect. In this way, the contact resistance can be reduced in the semiconductor device.

Semiconductor device and method of manufacturing thereof

A manufacturing method of a semiconductor device comprises a process of doping conductive impurities in a silicon carbide substrate, a process of forming a cap layer on a surface of the silicon carbide substrate, a process of activating the conductive impurities doped in the silicon carbide substrate, a process of oxidizing the cap layer after a first annealing process, and a process of removing the oxidized cap layer. It is preferred that the cap layer is formed from material that includes metal carbide. Since the oxidation onset temperature of metal carbide is comparatively low, the oxidization of the cap layer becomes easy if metal carbide is included in the cap layer. Specifically, it is preferred that the cap layer is formed from metal carbide that has an oxidation onset temperature of 1000 degrees Celsius or below, such as tantalum carbide.

Manufacturing method of a semiconductor device

A silicon carbide semiconductor device provided as a semiconductor chip includes a substrate, a drift layer on the substrate, an insulation film on the drift layer, a semiconductor element formed in a cell region of the drift layer, a surface electrode formed on the drift layer and electrically coupled to the semiconductor element through an opening of the insulation film, and a passivation film formed above the drift layer around the periphery of the cell region to cover an outer edge of the surface electrode. The passivation film has an opening through which the surface electrode is exposed outside. A surface of the passivation film is made uneven to increase a length from an inner edge of the opening of the passivation film to a chip edge measured along the surface of the passivation film.

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Toyota, Japan

Masaki Konishi