Hitachi, Ltd.

Renesas Technology Corp.

Renesas Electronics Corporation

Other

Murata Manufacturing Co., Ltd.

Hgst Netherlands, B.v.

Hitachi Vlsi Engineering Corp.

Hiroyuki Takazawa

Yasushi Shigeno

Shinya Osakabe

Shinichiro Takatani

Masao Yamane

Atsushi Kurokawa

Shigeki Koya

Takashi Ogawa

Yoshinori Imamura

Akishige Nakajima

Eigo Tange

Koji Hirata

Osamu Kagaya

Isao Ohbu

Tohru Oka

Kan Yasui

Masato Shiimoto

Nobuo Yoshida

Hidekatsu Onose

Masayoshi Kobayashi

Junji Shigeta

Hiroto Oda

Yukihiro Kawata

According to one embodiment, a magnetoresistive effect head includes a lower magnetic shield provided on a substrate, a magnetoresistive effect film laminated from a pinned layer with a pinned direction of magnetization, an intermediate layer, a free layer having a varying direction of magnetization controlled by an applied external magnetic field, a magnetic domain control layer formed with an intervening insulation layer on both sides in a track width direction of the magnetoresistive effect film, an upper magnetic shield, and electrodes for directing sense current flow in a direction perpendicular to a film surface of the magnetoresistive effect film, wherein a magnetic field applied by the magnetic domain control layer to a region away from an ABS of the free layer is at least 1.4 times larger than a magnetic field applied by the magnetic domain control layer to a region near the ABS of the free layer.

Magnetoresistive effect head having a free layer and a magnetic domain control layer that applies a magnetic field more strongly in an upper part of the free layer

A switching element is provided that realizes an stabilize a potential between the gates of the multi-gates without an increase in the insertion loss, and an antenna switch circuit and a radio frequency module each using the switch element. The switching element includes two ohmic electrodesformed on a semiconductor substrate, at least two gate electrodesdisposed between the two ohmic electrodes, and a conductive regiondisposed between the adjacent gate electrodes among the at least two gate electrodes, a field effective transistor being structured by the two ohmic electrodes, the at least two gate electrodes, and the conductive region. The conductive region has a wider portion that is wider in width than the conductive region interposed between the adjacent gate electrodes on one end thereof. The distance between the adjacent gate electrodes is narrower than the width of the wider portion. Resistorsare connected in series between the two ohmic electrodes through the wider portion.

Switching element, antenna switch circuit and radio frequency module using the same

The present invention miniaturizes a HEMT element used as a switching element in a radio frequency module. A single gate electrodeis formed in an active region defined by an element separation portionon a main surface of a substratecomprising GaAs. The gate electrodeis patterned so as to extend in the vertical direction of the page surface between source electrodesand drain electrodes, and to extend in left and right directions at other portions. Thus, the ratio of the gate electrodedisposed outside the active region is reduced, and the area of a gate padA is reduced.

Semiconductor device

A UMOSFET is capable of reducing a threshold voltage and producing a large saturation current. A typical UMOSFET according to the present invention includes: an Ntype SiC substrate constituting a drain layer; an Ntype SiC layer that is in contact with the drain layer and constitutes a drift layer; a P type body layer formed on the drift layer and being a semiconductor layer; an Ntype SiC layer constituting a source layer; a trench extending from the source layer to a predetermined location placed in the drift layer; a P type electric field relaxation region provided around and outside a bottom portion of the trench; and a channel region extending from the Ntype source layer to the P type electric field relaxation region and having an impurity concentration higher than that of the Ntype drift layer and lower than that of the P type body layer.

Semiconductor device and electrical circuit device using thereof

The present invention provides a semiconductor device for high frequency application having a high breakdown voltage and the method of manufacturing thereof. A region including a first conductivity type high impurity concentration semiconductor and a region including a first conductivity type low impurity concentration semiconductor are provided from an ohmic layer side at the side far from a semiconductor substrate of the end surface of a barrier layer opposite the semiconductor substrate and between the ohmic layer and a gate electrode. The sheet impurity concentration of the region including a first conductivity type low impurity concentration semiconductor is set to be lower than that between the bottom surface of the gate electrode at the side of the semiconductor substrate and the end surface of the channel layer opposite the semiconductor substrate. The sheet impurity concentration of the region including a first conductivity type high impurity concentration semiconductor is set to be higher than that of the region including a first conductivity type low impurity concentration semiconductor.

Compound semiconductor having a doped layer between the gate and an ohmic contact of an active region

A semiconductor device comprising a bipolar transistor having an emitter layer consisting of a semiconductor containing indium, and a protective insulating film containing silicon and oxygen which is formed on the surface of the guard ring of the emitter layer, wherein the protective insulating film has a density of oxygen of less than 7&times;10 cm . This semiconductor device prevents performance deterioration and ensures high performance in a power amplifier.

Semiconductor device and power amplifier using the same

A semiconductor device including a bipolar transistor having an emitter layer consisting of a semiconductor containing indium, and a protective insulating film containing silicon and oxygen which is formed on the surface of the guard ring of the emitter layer, wherein the protective insulating film has a density of oxygen of less than 7&times;10 cm . This semiconductor device prevents performance deterioration and ensures high performance in a power amplifier.

To provide a super high-speed heterojunction bipolar transistor, a semiconductor device including such a heterojunction bipolar transistor has a structure wherein a subcollector layer, collector layer, base layer, emitter layer (InGaP layer) and emitter cap layer are successively formed in predetermined shapes a surface of a semi-insulating GaAs substrate, an inner edge part of a base electrode overlaps a periphery of the emitter layer, and the base electrode is electrically connected to the base layer by an alloy layer formed by alloying the emitter layer under the base electrode. The emitter layer is selectively formed on the base layer. The base electrode extends from the peripheral part of the emitter layer across the base layer, and the alloy layer extends to a midway depth of the base layer. The edge of the base layer is situated further inside than the outer edge of the base electrode.

High speed heterojunction bipolar transistor, and RF power amplifier and mobile communication system using the same

A compound semiconductor integrated circuit having a high resistance layer consisting of a compound semiconductor to which oxygen is added as an impurity and an undoped compound semiconductor layer which are formed between a semi-insulating substrate and field effect transistors formed thereon sequentially from the semi-insulating substrate side is suited to a superspeed operation because the low frequency oscillation is suppressed.

Compound semiconductor integrated circuit with a particular high

By forming an isolated semiconductor layer or electrode layer on a semiconductor surface between neighboring field effect transistors and element separating trenches which are deep enough to reach at least the semi-insulating substrate or the hetero junction interface on the buffer layer, low frequency oscillation of a compound semiconductor integrated circuit can be reduced. By controlling the thickness of the buffer layer having a hetero junction to at most 150 nm, the low frequency oscillation can be reduced. By forming materials separating adjacent elements with a width of at most 2 .mu.m which reach from the element region surface to the buffer layer having hetero junction so as to enclose the element regions and etched regions in the neighborhood of the elements or so as to enclose the element regions in the etched regions and by controlling the angle of the sides of the etched regions against the semiconductor layer surface to 10.degree. to 60.degree., wires can be prevented from short-circuiting.

Growing community of inventors

Hino, Japan

Hiroyuki Takazawa