Oki Electric Industry Co., Ltd.

Fujikura Limited

Calsonic Corporation

Xerox Corporation

Kohwa Manufacturing Co., Ltd.

Kohwa Mfg. Co.

Masanori Itoh

Shinichi Hoshi

Ken-ichi Uruga

Takao Suzuki

Hisanaga Hirabayashi

Hitoshi Okuyama

Kiyoshi Yajima

Toshiharu Marui

Hideyuki Okita

Keita Nakano

Shuko Yamamoto

An opening for forming a gate electrode is provided by a first photoresist pattern formed on an insulating film. Reactive ion etching by inductively coupled plasma is applied to the insulating film through the first photoresist pattern as a mask to thereby expose the surface of a GaN semiconductor layer, evaporating thereon a gate metal such as NiAu, thereby forming the gate electrode by self-aligned process. This prevents an oxidized film from being formed on the surface of the semiconductor layer. After the gate electrode is formed, a second photoresist pattern is formed to form a field plate on the gate electrode and the insulating film through the second photoresist pattern as a mask. Thereby, Ti having a high adhesiveness with an insulating film made of SiN or the like can be used as a field plate metal.

Method for manufacturing a field effect transistor having a field plate

The present invention provides a semiconductor device having a recess-structured ohmic electrode, in which the resistance is small and variation in the resistance value caused by manufacturing irregularities is small. In the semiconductor device of the present invention, a two-dimensional electron gas layer is formed on the interface between a channel-forming layer and a Schottky layer by electrons supplied from the Schottky layer. The ohmic electrode comprises a plurality of side faces in ohmic contact with the two-dimensional electron gas layer. At least a part of side faces of the ohmic electrodes are non-parallel to a channel width direction. In a preferred embodiment of the present invention, the side faces have a saw tooth form or a comb tooth form. Since the contact area between the ohmic electrode and the two-dimensional electron gas layer is increased, ohmic resistance is reduced.

Semiconductor device having ohmic recessed electrode

A semiconductor device is provided which is capable of reducing direct current resistance in a signal line, of reducing a high-frequency resistance even in the case of transmitting high-frequency signals and, therefore, of increasing power gain when employed in, for example, an MMIC for high power. The semiconductor device has a microstrip line containing an interlayer dielectric and signal line formed on a semiconductor substrate on which predetermined circuit devices are mounted, wherein the signal line is made multi-layered with the interlayer dielectric interposed among the multiple layers and wherein the interlayer dielectric is made so thin that pin holes are produced and each layer constituting the signal line is electrically connected to each other through the pin holes.

Semiconductor device and method of manufacturing the same

A semiconductor device and a method of manufacturing the same are provided which are novel and fully improved and are capable of lowering satisfactorily a high-frequency resistance or direct current resistance in a signal line. The semiconductor device is composed of a semiconductor substrate on which predetermined circuit devices are mounted, an insulating film formed on the substrate in a manner that it covers the circuit devices and a conductive path formed on the insulating film to electrically connect the circuit devices. A concave trench is formed in a predetermined position on the semiconductor substrate and the conductive path is formed at a bottom of the concave trench in a manner that it extends along the concave trench, with interlayer dielectrics interposed between conductive layers constituting the conductive path.

Method of manufacturing a semiconductor device with a concave trench

A device evaluation circuit capable of easily matching the impedance of a mounted IC to be measured to that of a measurement system. In the device evaluation circuit, a ceramic head used to improve durability of the device evaluation circuit comprises a base and, for example, ceramic plates. Micro strip lines electrically connected to corresponding micro strip lines of a substrate are respectively formed on the ceramic plates. Further, ground patterns are respectively formed on the ceramic plates. Matching devices are implemented between the micro strip line and the ground patterns and between the micro strip line and the ground patterns respectively so that impedance matching is easily done in the neighborhood of an IC to be measured.

Device evaluation circuit

A flat resistance for a blower control unit of an automobile air conditioner, and a blower control unit using the same. The flat resistance includes: a porcelain enameled metallic substrate including a flat head portion, having an edge and one surface, and parallel terminal supporting portions projecting outwardly from the edge of the head; a resistance circuit printed on the one surface of the head portion, the resistance circuit including a plurality of resistances electrically connected in series; a temperature fuse, interposed in the resistance circuit, for being tripped to break the resistance circuit when the porcelain enameled metallic substrate becomes overheated; and terminals, printed on both the head portion and the terminal supporting portions, each terminal being connected to one end of a corresponding one of the resistances.

Flat resistance for blower control unit for automobile air conditioner

Flat resistance for blower control unit of automobile air conditioner

An electrostatic recording medium for use in an electrographic process for forming an electrostatic latent image, and method for making such a recording medium, which includes a base, a resistance layer on the base, an adhesive layer on the resistance layer and a recording layer laminated to the resistance layer through the adhesive layer, the adhesive layer being made of a mateial so that the volume resistivity of the resultant recording medium is relatively unaffected by changes in humidity conditions.

Growing community of inventors

Tokyo, Japan

Masanori Itoh