Abstract: A semiconductor device includes: a channel layer not containing Al; a barrier layer above the channel layer containing Al; a recess; and an ohmic electrode in the recess, which is in ohmic contact with a two-dimensional electron gas layer. An Al composition ratio distribution of the barrier layer has a maximum point at a first position. The semiconductor device includes: a first inclined surface of the barrier layer which includes the first position and is in contact with the ohmic electrode; and a second inclined surface of the barrier layer which intersects the first inclined surface on a lower side of the first inclined surface, and is in contact with the ohmic electrode. To the surface of the substrate, an angle of the second inclined surface is smaller than an angle of the first inclined surface. A position of the first intersection line is lower than the first position.

Abstract: A semiconductor device for power amplification includes: a source electrode, a drain electrode, and a gate electrode disposed above a semiconductor stack structure including a first nitride semiconductor layer and a second nitride semiconductor layer; and a source field plate that is disposed above the semiconductor stack structure between the gate electrode and the drain electrode, and has a same potential as a potential of the source electrode. The source field plate has a staircase shape, and even when length LF2 of an upper section is increased for electric field relaxation, an increase in parasitic capacitance Cds generated between the source field plate and a 2DEG surface is inhibited.

Abstract: A semiconductor device includes: a channel layer not containing Al; a barrier layer above the channel layer containing Al; a recess; and an ohmic electrode in the recess, which is in ohmic contact with a two-dimensional electron gas layer. An Al composition ratio distribution of the barrier layer has a maximum point at a first position. The semiconductor device includes: a first inclined surface of the barrier layer which includes the first position and is in contact with the ohmic electrode; and a second inclined surface of the barrier layer which intersects the first inclined surface on a lower side of the first inclined surface, and is in contact with the ohmic electrode. To the surface of the substrate, an angle of the second inclined surface is smaller than an angle of the first inclined surface. A position of the first intersection line is lower than the first position.

Abstract: A resistive element that includes: a substrate; a first nitride semiconductor layer; a second nitride semiconductor layer; a two-dimensional electron gas layer on the first nitride semiconductor layer side at an interface between the first nitride semiconductor layer and the second nitride semiconductor layer; a first electrode ohmically connected to the two-dimensional electron gas layer; a second electrode ohmically connected to the two-dimensional electron gas layer; and an insulating layer between the first electrode and the second electrode in plan view. The two-dimensional electron gas layer functions as an electric resistance element. A conductive layer is not provided above the insulating layer between the first electrode and the second electrode in the plan view. The resistive element has a resistance-value stabilization structure that functions to keep a resistance value of the electric resistance element constant.

Abstract: A resistive element that includes: a substrate; a first nitride semiconductor layer; a second nitride semiconductor layer; a two-dimensional electron gas layer on the first nitride semiconductor layer side at an interface between the first nitride semiconductor layer and the second nitride semiconductor layer; a first electrode ohmically connected to the two-dimensional electron gas layer; a second electrode ohmically connected to the two-dimensional electron gas layer; and an insulating layer between the first electrode and the second electrode in plan view. The two-dimensional electron gas layer functions as an electric resistance element. A conductive layer is not provided above the insulating layer between the first electrode and the second electrode in the plan view. The resistive element has a resistance-value stabilization structure that functions to keep a resistance value of the electric resistance element constant.

Abstract: A pushbutton switch member has a dome-shaped movable contact and an operation key facing and separated from a movable contact. Pushing the operation key toward the movable contact causes the movable contact to electrically connect at least two contacts on a substrate. The operation key is provided with: a key; a dome connected with an outer periphery of the key, and deformable by pushing of the key toward the substrate; and a foot connected with an outer periphery of the dome, and fixed on the substrate. The movable contact is provided with: an upper contact spaced apart from a site directly below the key, and which makes contact with a contact when the key is pushed in; and an outer fixing part disposed at the upper contact, or further outside thereof in the radial direction, and fixed outside of the key in the radial direction.

Abstract: A pushbutton switch includes: a dome-shaped movable contact; and an operation key on a side of the movable contact. Pushing the operation key causes the movable contact to electrically connect at least two contacts. The operation key includes: a key body; a dome connected with an exterior of the key body and deformable by pushing the key body; a foot connected with an exterior of the dome; and a protrusion on top of the key body, protruding from the top, and deformable by compression. The movable contact includes: an upper contact in contact with a site below the key body and contacting the at least two contacts when the key body is pushed; and an outer fixing part at the upper contact in a radial direction and fixed outside of the key body of the operation key in the radial direction.

Abstract: A pushbutton switch includes: a dome-shaped movable contact; and an operation key on a side of the movable contact. Pushing the operation key causes the movable contact to electrically connect at least two contacts. The operation key includes: a key body; a dome connected with an exterior of the key body and deformable by pushing the key body; a foot connected with an exterior of the dome; and a protrusion on top of the key body, protruding from the top, and deformable by compression. The movable contact includes: an upper contact in contact with a site below the key body and contacting the at least two contacts when the key body is pushed; and an outer fixing part at the upper contact in a radial direction and fixed outside of the key body of the operation key in the radial direction.

Abstract: A pushbutton switch member has a dome-shaped movable contact and an operation key facing and separated from a movable contact. Pushing the operation key toward the movable contact causes the movable contact to electrically connect at least two contacts on a substrate. The operation key is provided with: a key; a dome connected with an outer periphery of the key, and deformable by pushing of the key toward the substrate; and a foot connected with an outer periphery of the dome, and fixed on the substrate. The movable contact is provided with: an upper contact spaced apart from a site directly below the key, and which makes contact with a contact when the key is pushed in; and an outer fixing part disposed at the upper contact, or further outside thereof in the radial direction, and fixed outside of the key in the radial direction.

Abstract: Method for manufacturing a semiconductor device. A channel layer is formed by epitaxially growing a semiconductor layer, in which an ion species of a first conductivity is implanted on a semiconductor substrate. A source region, a drain region, and an emitter region which are of the first conductivity, are formed by activating, using annealing, a portion of the semiconductor substrate in which the ion species has been implanted. An emitter layer of the first conductivity, a base layer of a second conductivity having a band gap smaller than a band gap of the emitter layer, and a collector layer of the first conductivity or a non-doped collector layer are sequentially and epitaxially grown on the channel layer.

Abstract: A semiconductor device and manufacturing method satisfies both of the trade-off characteristic advantages of the HBT and the HFET. The semiconductor device is an HBT and HFET integrated circuit. The HBT includes a sub-collector layer, a GaAs collector layer, a GaAs base layer, and an InGaP emitter layer that are sequentially stacked. The sub-collector layer includes a GaAs external sub-collector region, and a GaAs internal sub-collector region disposed on the GaAs external sub-collector region. A mesa-shaped collector part and a collector electrode are separately formed on the GaAs external sub-collector region. The HFET includes a GaAs cap layer, a source electrode, and a drain electrode. The GaAs cap layer includes a portion of the GaAs external sub-collector region. The source electrode and the drain electrode are formed on the GaAs cap layer.

Abstract: The object of the present invention is to provide a semiconductor device and the manufacturing method thereof which are capable of preventing decrease in the collector breakdown voltage and reducing the collector resistance. The semiconductor device according to the present invention includes: a HBT formed on a first region of a semiconductor substrate; and an HFET formed on a second region of the semiconductor substrate, wherein the HBT includes: an emitter layer of a first conductivity; a base layer of a second conductivity that has a band gap smaller than that of the emitter layer; a collector layer of the first conductivity or a non-doped collector layer; and a sub-collector layer of the first conductivity which are formed sequentially on the first region, and the HFET includes an electron donor layer including a part of the emitter layer, and a channel layer formed under the electron donor layer.

Abstract: An object of the present invention is to provide a semiconductor resistive element having excellent linearity. A semiconductor device according to the present invention includes a HBT which is formed on a GaAs substrate and includes a group III-V compound semiconductor, and a semiconductor resistive element made of at least one layer included in a semiconductor epitaxial layer included in the HBT, and the semiconductor resistive element includes helium impurities.

Abstract: An HBT according to this invention includes: a sub-collector layer; a collector layer formed on the sub-collector layer and the base layer including a first collector layer, a second collector layer, a third collector layer, and a fourth collector layer. The first collector layer is formed on the sub-collector layer, and is made of semiconductor different from semiconductor of which the second to the fourth collector layers are made. The fourth collector layer is formed on the first collector layer, and has an impurity concentration lower than an impurity concentration of the second collector layer. The second collector layer is formed on the fourth collector layer, and has an impurity concentration lower than an impurity concentration of the sub-collector layer and higher than an impurity concentration of the third collector layer. The third collector layer is formed between the second collector layer and the base layer.

Abstract: The object of the present invention is to provide a heterojunction bipolar transistor with high breakdown tolerance which can be manufactured at a high reproducibility and a high yield, the heterojunction bipolar transistor includes: a sub-collector layer; a collector layer formed on the sub-collector layer; a base layer formed on the collector layer; and an emitter layer, which is formed on the base layer and is made of a semiconductor that has a larger bandgap than a semiconductor of the base layer, in which the collector layer includes: a first collector layer formed on the sub-collector layer; a second collector layer formed on the first collector layer; and a third collector layer formed between the second collector layer and the base layer, a semiconductor of the first collector layer differs from semiconductors of the third collector layer and the second collector layer, and an impurity concentration of the second collector layer is lower than an impurity concentration of the sub-collector layer and hi

Abstract: The present invention has as an objective to provide: a semiconductor device to satisfy both of the trade-off characteristic advantages of the HBT; and the HFET and a manufacturing method thereof. The semiconductor device in the present invention is an HBT and HFET integrated circuit. The HBT includes a sub-collector layer, a GaAs collector layer, a GaAs base layer, and an InGaP emitter layer which are sequentially stacked. The sub-collector layer includes a GaAs external sub-collector region, and a GaAs internal sub-collector region disposed on the GaAs external sub-collector region. A mesa-shaped collector part and a collector electrode are separately formed on the GaAs external sub-collector region. The HFET includes a GaAs cap layer, a source electrode, and a drain electrode, the GaAs cap layer including portion of the GaAs external sub-collector region, and the source electrode and the drain electrode being formed on the GaAs cap layer.

Abstract: The object of the present invention is to provide a semiconductor device and the manufacturing method thereof which are capable of preventing decrease in the collector breakdown voltage and reducing the collector resistance. The semiconductor device according to the present invention includes: a HBT formed on a first region of a semiconductor substrate; and an HFET formed on a second region of the semiconductor substrate, wherein the HBT includes: an emitter layer of a first conductivity; a base layer of a second conductivity that has a band gap smaller than that of the emitter layer; a collector layer of the first conductivity or a non-doped collector layer; and a sub-collector layer of the first conductivity which are formed sequentially on the first region, and the HFET includes an electron donor layer including a part of the emitter layer, and a channel layer formed under the electron donor layer.

Abstract: On a high-concentration n-type first sub-collector layer, a high-concentration n-type second sub-collector layer made of a material having a small bandgap, an i-type or low-concentration n-type collector layer, a high-concentration p-type base layer, an n-type emitter layer made of a material having a large bandgap, a high-concentration n-type emitter cap layer, a high-concentration n-type emitter contact layer made of a material having a small bandgap are sequentially stacked. From the emitter contact layer, an interconnection also serving as an emitter electrode is extended. From the emitter layer or the base layer, an interconnection also serving as a base electrode is extended. From the second sub-collector layer, an interconnection also serving as a collector electrode is extended.

Abstract: The present invention has an object of providing a method for manufacturing a semiconductor device which can prevent occurrence of pattern abnormality of an electrode and deterioration of an electronic property. The method for manufacturing the semiconductor device including a GaAs substrate with a portion made of GaAs includes: forming a Ti/Pt/Au/Ti electrode on the GaAs substrate, the electrode including Pt and having a layered structure in which a top layer made of Ti; forming a collector electrode including AuGe on a portion made of GaAs; and performing heat treatment on the collector electrode in a state where both of the Ti/Pt/Au/Ti electrode and the collector electrode are exposed to a surface.

Abstract: Provided is a semiconductor device and a manufacturing method of the same which improve adhesion of a semiconductor substrate to a metal wire, the semiconductor substrate having a via hole formed from a bottom surface of the semiconductor substrate up to the metal wire on a top surface of the semiconductor substrate, and the metal wire being positioned on the top surface of the semiconductor substrate where there is an opening formed since the via hole is formed. The semiconductor device includes: a metal layer formed on a semiconductor substrate; an alloy reaction layer formed below the metal layer as a result of an alloy reaction between the semiconductor substrate and the metal layer; and a via hole formed from a bottom surface side of the semiconductor substrate up to the metal layer or up to the alloy reaction layer.