On a single-crystal semiconductor substrate with an upper surface including a first direction in which an inverted mesa step extends and a second direction in which a forward mesa step extends in response to anisotropic etching in which an etching rate depends on crystal plane orientation, a bipolar transistor including a collector layer, a base layer, and an emitter layer that are epitaxially grown, and a base wire connected to the base layer are arranged. A step is provided at an edge of the base layer, and the base wire is extended from inside to outside of the base layer in a direction intersecting the first direction in a plan view. An intersection of the edge of the base layer and the base wire has a disconnection prevention structure that makes it difficult for step-caused disconnection of the base wire to occur.

A lateral transistor tile is formed with first and second collector regions that longitudinally span first and second sides of the transistor tile; and a base region and an emitter region that are between the first and second collector regions and are both centered on a longitudinal midline of the transistor tile. A base-collector current, a collector-emitter current, and a base-emitter current flow horizontally; and the direction of the base-emitter current is perpendicular to the direction of the base-collector current and the collector-emitter current. Lateral BJT transistors having a variety of layouts are formed from a plurality of the tiles and share common components thereof.

A heterojunction bipolar transistor includes: a substrate; a base mesa disposed on the substrate, wherein the base mesa includes a collector layer and a base layer disposed on the collector layer, and wherein in a top view, the base layer includes a first edge and a second edge opposite to the first edge; an emitter layer disposed on the base layer; a base electrode disposed on the substrate and connected to the base layer; a dielectric layer disposed on the base electrode, wherein a first via hole is formed in the dielectric layer at the first edge of the base layer, and a second via hole is formed in the dielectric layer at the second edge of the base layer; and a conductive feature disposed on the dielectric layer, wherein the conductive feature is connected to the base electrode through the first via hole and the second via hole.

A heterojunction bipolar transistor includes an emitter layer on a base layer on a collector layer on an upper sub-collector layer over a bottom sub-collector layer, a first dielectric film over the bottom sub-collector layer, the base layer and the emitter layer, a base electrode on the first dielectric film, electrically connected to the base layer through at least one first via hole in the first dielectric film, a second dielectric film on the first dielectric film and the base electrode, and a conductive layer on the second dielectric film, with conductive layer electrically connected to base electrode through a second via hole disposed in the second dielectric film, first dielectric film between the base electrode and first sidewall of a stack including the base layer and the collector layer, and second via hole laterally separated from the base layer.

A semiconductor device includes a plurality of unit transistors that are arranged on a surface of a substrate in a first direction. Input capacitive elements are arranged so as to correspond to the unit transistors. An emitter common wiring line is connected to emitter layers of the unit transistors. A via-hole extending from the emitter common wiring line to a back surface of the substrate is disposed at a position overlapping the emitter common wiring line. A collector common wiring line is connected to collector layers of the unit transistors. The input capacitive elements, the emitter common wiring line, the unit transistors, and the collector common wiring line are arranged in this order in a second direction. Base wiring lines that connect the input capacitive elements to base layers of the corresponding unit transistors intersect the emitter common wiring line without physical contact.

A lateral transistor tile is formed with first and second collector regions that longitudinally span first and second sides of the transistor tile; and a base region and an emitter region that are between the first and second collector regions and are both centered on a longitudinal midline of the transistor tile. A base-collector current, a collector-emitter current, and a base-emitter current flow horizontally; and the direction of the base-emitter current is perpendicular to the direction of the base-collector current and the collector-emitter current. Lateral BJT transistors having a variety of layouts are formed from a plurality of the tiles and share common components thereof.

Bipolar junction transistor (BJT) structures are provided. A BJT structure includes a semiconductor substrate, a collector region formed in the semiconductor substrate, a base region formed over the collector region, an emitter region formed over the collector region, a ring-shaped shallow trench isolation (STI) region formed in the collector region, and a base dielectric layer formed over the collector region and on opposite sides of the base region. The base dielectric layer is surrounded by an inner side wall of the ring-shaped STI region.

A semiconductor device includes a collector layer, a base layer, and an emitter layer that are disposed above a substrate. An emitter mesa layer is disposed on a partial region of the emitter layer. In a plan view, the base electrode is disposed in or on a region which does not overlap the emitter mesa layer. The base electrode allows base current to flow to the base layer. In the plan view, a first edge forming part of edges of the emitter mesa layer extends in a first direction, and a second edge forming part of edges of the base electrode faces the first edge. A gap between the first edge and the second edge in a terminal portion located in an end portion of the emitter mesa layer in the first direction is wider than a gap in an intermediate portion of the emitter mesa layer.

At least one unit transistor is arranged over a substrate. A first wiring as a path of current that flows to each unit transistor is arranged over the at least one unit transistor. An inorganic insulation film is arranged over the first wiring. At least one first opening overlapping a partial region of the first wiring in a plan view is provided in the inorganic insulation film. An organic insulation film is arranged over the inorganic insulation film. A second wiring coupled to the first wiring through the first opening is arranged over the organic insulation film and the inorganic insulation film. In a plan view, a region in which the organic insulation film is not arranged is provided outside a region in which the first wiring is arranged. The second wiring is in contact with the inorganic insulation film outside the region in which the first wiring is arranged.

An advanced moisture resistant structure of compound semiconductor integrated circuit comprises a compound semiconductor substrate, a compound semiconductor epitaxial structure, a compound semiconductor integrated circuit and a moisture barrier layer. The compound semiconductor epitaxial structure is formed on the compound semiconductor substrate. The compound semiconductor integrated circuit is foimed on the compound semiconductor epitaxial structure. The moisture barrier layer is formed on the compound semiconductor integrated circuit. The moisture barrier layer is made of A1.sub.2O.sub.3. The thickness of the moisture barrier layer is greater than or equal to 400 Å and less than or equal to 1000 Å so as to enhance the moisture resistant ability of the compound semiconductor integrated circuit.