Denso Corporation

Kazuhiro Oyama

Yasushi Higuchi

Shinichi Hoshi

Youngshin Eum

Takayuki Shibata

Yuki Anno

Masahiko Ogura

Toshiharu Makino

Satoshi Yamasaki

Hiromitsu Kato

Masaki Matsui

Daisuke Takeuchi

Norio Tokuda

Hiroyuki Tarumi

Seigo Oosawa

Takao Inokuma

Yoshinori Tsuchiya

Takuma Minamiyama

A magnetic field generator includes: an upper layer resonance coil composed of a first conductive material and forming a loop circuit having a coil portion; a lower layer coil composed of a second conductive material and forming a loop circuit having a coil portion arranged opposite to the coil portion of the upper layer coil at a predetermined distance; and a substrate supporting the upper layer coil and the lower layer coil and having a dielectric material between the upper layer coil and the lower layer coil. A high-frequency current is supplied to the lower layer coil and a high-frequency current having a phase opposite to that of the high frequency current supplied to the lower layer coil flows through the upper layer coil. A length per loop of the coil portion in the upper layer coil and the coil portion in the lower layer coil is matched to one wavelength of the high-frequency current.

Magnetic field generator having a high frequency current lower layer coil and a resonance upper layer coil

A magnetic field generator includes: an upper layer coil composed of a first conductive material and forming a loop circuit having a coil portion; a lower layer coil composed of a second conductive material and forming a loop circuit having a coil portion arranged opposite to the coil portion of the upper layer coil at a predetermined distance; and a substrate supporting the upper layer coil and the lower layer coil and having a dielectric material between the upper layer coil and the lower layer coil. High-frequency currents of opposite phases are passed through the upper layer coil and the lower layer coil, respectively, and a length per loop of the coil portion in the upper layer coil and the coil portion in the lower layer coil is matched to one wavelength of the high-frequency current.

Magnetic field generator and magnetic sensor having the same

In a semiconductor device with a wide gap semiconductor, a gate insulating film is made of a material having a barrier against a minor carrier in an n-type body layer and having no barrier against a minor carrier in a p-type drift layer. As a result, in the semiconductor device with the wide gap semiconductor, a reduction in a conduction loss can be achieved while realizing an improvement in blocking resistance and securing reliability of the gate insulating film.

Semiconductor device and circuit having the same

A semiconductor device includes a conductive substrate, a channel forming layer, a first electrode, and a second electrode. The channel forming layer is located above the conductive substrate and includes at least one hetero-junction structure. The hetero-junction structure includes a first GaN-type semiconductor layer providing a drift region and a second GaN-type semiconductor layer having a bandgap energy greater than the first GaN-type semiconductor layer. A total fixed charge quantity of charges in the first GaN-type layer and the second GaN-type layer is from 0.5&#xd7;10to 1.5&#xd7;10cm. The charges in the first GaN-type layer and the second GaN-type layer include charges generated by the polarization in the first GaN-type layer. Accordingly, the semiconductor device capable of improving a break-down voltage and decreasing an on-resistance is obtained.

Semiconductor device

A semiconductor device has a lateral switching device that includes a channel forming layer, a gate structure portion, a source electrode, a drain electrode, a third semiconductor layer, a fourth semiconductor layer, and a junction gate electrode. The gate structure portion has a gate insulating film provided in a recess portion of the channel forming layer and a MOS gate electrode functioning as a gate electrode of a MOS structure provided on the gate insulating film. The source electrode and the junction gate electrode are coupled through an electrode layer provided on an interlayer insulating film covering the MOS gate electrode. An end of the third semiconductor layer facing the drain electrode protrudes toward the drain electrode from an end of the fourth semiconductor layer facing the drain electrode by a distance in a range of 1 &#x3bc;m to 5 &#x3bc;m both inclusive.

Semiconductor device including switching device having four-terminal structure

A nitride semiconductor device includes a horizontal switching device that includes a substrate, a channel forming layer, a source region, a drain region and a gate region. The source region and the drain region are arranged apart from each other in one direction along a plane of the substrate. The gate region is formed of a p-type semiconductor layer and is arranged between the source region and the drain region. The gate region is divided into multiple parts in a perpendicular direction along the plane of the substrate, the perpendicular direction being perpendicular to an arrangement direction in which the source region and the drain region are arranged. Accordingly, on-resistance is decreased while securing high breakdown voltage.

Nitride semiconductor device including a horizontal switching device

A semiconductor device includes a lateral switching device having: a substrate; a channel forming layer that has a heterojunction structure made of a GaN layer and an AlGaN layer and is formed with a recessed portion, on the substrate; a gate structure part that includes a gate insulating film and a gate electrode formed in the recessed portion; and a source electrode and a drain electrode on opposite sides of the gate structure part on the channel forming layer. The AlGaN layer includes a first AlGaN layer that has an Al mixed crystal ratio determining a two dimensional electron gas density, and a second AlGaN layer that has an Al mixed crystal ratio smaller than that of the first AlGaN layer to induce negative fixed charge, and is disposed in contact with the gate structure part and spaced from the source electrode and the drain electrode.

In a semiconductor device, an AlGaN layer includes a first AlGaN layer and a second AlGaN layer. The second AlGaN layer is positioned between a gate structure portion and a drain electrode and is divided into multiple parts in an arrangement direction in which the gate structure portion and the drain electrode are arranged. A second Al mixed crystal ratio of the second AlGaN layer is less than a first Al mixed crystal ratio of the first AlGaN layer. Accordingly, the semiconductor device is a normally-off-type device and is capable of restricting a decrease of a breakdown voltage and an increase of an on-resistance.

A protection circuit of a semiconductor device includes a high electron mobility transistor and a protection element. Between the drain and the gate of the high electron mobility transistor, the protection element includes: a thyristor; and a first resistor connected in series to the thyristor. Between the source and the gate of the high electron mobility transistor, the protection element includes: a second resistor and an interrupter that is connected in series to the second resistor. The interrupter interrupts a flow of a current between the drain and the gate when the thyristor is turned off, and the interrupter permits the current to flow between the drain and the gate when the thyristor is turned on.

Protection circuit of semiconductor device

A semiconductor device includes a MISFET having: a diamond substrate; a drift layer having a first layer with a first density for providing a hopping conduction and a second layer with a second density lower than the first density, and having a &#x3b4; dope structure; a body layer on the drift layer; a source region in an upper portion of the body layer; a gate insulation film on a surface of the body layer; a gate electrode on a surface of the gate insulation film; a first electrode electrically connected to the source region and a channel region; and a second electrode electrically connected to the diamond substrate. The MISFET flows current in the drift layer in a vertical direction, and the current flows between the first electrode and the second electrode.

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Kariya, Japan

Kazuhiro Oyama