The present disclosure relates to a semi-conductor structure and method for co-integrating a III-V device with a group IV device on a Si.sub.xGe.sub.1-x(100) substrate. The method includes: (a) providing a Si.sub.xGe.sub.1-x(100) substrate, where x is from 0 to 1; (b) selecting a first region for forming therein a group IV device and a second region for forming therein a III-V device, the first and the second region each comprising a section of the Si.sub.xGe.sub.1-x(100) substrate; (c) forming a trench isolation for at least the III-V device; (d) providing a Si.sub.yGe.sub.1-y(100) surface in the first region, where y is from 0 to 1; (e) at least partially forming the group IV device on the Si.sub.yGe.sub.1-y(100) surface in the first region; (f) forming a trench in the second region which exposes the Si.sub.xGe.sub.1-x(100) substrate, the trench having a depth of at least 200 nm, at least 500 nm, at least 1 μm, usually at least 2 μm, such as 4 μm, with respect to the Si.sub.yGe.sub.1-y(100) surface in the first region; (g) growing a III-V material in the trench using aspect ratio trapping; and (h) forming the III-V device on the III-V material, the III-V device comprising at least one contact region at a height within 100 nm, 50 nm, 20 nm, usually 10 nm, of a contact region of the group IV device.

A vertical high-blocking III-V bipolar transistor, which includes an emitter, a base and a collector. The emitter has a highly doped emitter semiconductor contact region of a first conductivity type and a first lattice constant. The base has a low-doped base semiconductor region of a second conductivity type and the first lattice constant. The collector has a layered low-doped collector semiconductor region of the first conductivity type with a layer thickness greater than 10 μm and the first lattice constant. The collector has a layered highly doped collector semiconductor contact region of the first conductivity type. A first metallic connecting contact layer is formed in regions being integrally connected to the emitter. A second metallic connecting contact layer is formed in regions being integrally connected to the base. A third metallic connecting contact region is formed at least in regions being arranged beneath the collector.

A compound semiconductor device includes a heterojunction bipolar transistor and a bump. The heterojunction bipolar transistor includes a plurality of unit transistors. The bump is electrically connected to emitters of the plurality of unit transistors. The plurality of unit transistors are arranged in a first direction. The bump is disposed above the emitters of the plurality of unit transistors while extending in the first direction. The emitter of at least one of the plurality of unit transistors is displaced from a center line of the bump in the first direction toward a first side of a second direction which is perpendicular to the first direction. The emitter of at least another one of the plurality of unit transistors is displaced from the center line of the bump in the first direction toward a second side of the second direction.

In one example, a sensor includes a heterojunction bipolar transistor and component sensing surface coupled to the heterojunction bipolar transistor via an extended base component. In another example, a biosensor for detecting a target analyte includes a heterojunction bipolar transistor and a sensing surface. The heterojunction bipolar transistor includes a semiconductor emitter including an emitter electrode for connecting to an emitter voltage, a semiconductor collector including a collector electrode for connecting to a collector voltage, and a semiconductor base positioned between the semiconductor emitter and the semiconductor collector. The sensing surface is coupled to the semiconductor base of the heterojunction bipolar transistor via an extended base component and includes a conducting film and a reference electrode.

This disclosure relates to methods for forming bipolar transistors, such as heterojunction bipolar transistors, having at least one grading in the collector. In some embodiments, the methods include forming a sub-collector. In some embodiments the methods include forming a primary collector region with at least one grading having a doping concentration that decreases away from the sub-collector. In some embodiments the methods further include forming a secondary collector region to abut a base of the bipolar transistor and having a doping concentration of at least about 3×10.sup.16 cm.sup.−3 at an interface with the base. Such bipolar transistors can be implemented, for example, in power amplifiers.

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 method for manufacturing an epitaxial wafer comprising a silicon carbide substrate and a silicon carbide voltage-blocking-layer, the method includes: epitaxially growing a buffer layer on the substrate, doping a main dopant for determining a conductivity type of the buffer layer and doping an auxiliary dopant for capturing minority carriers in the buffer layer at a doping concentration less than the doping concentration of the main dopant, so that the buffer layer enhances capturing and extinction of the minority carriers, the minority carriers flowing in a direction from the voltage-blocking-layer to the substrate, so that the buffer layer has a lower resistivity than the voltage-blocking-layer, and so that the buffer layer includes silicon carbide as a main component; and epitaxially growing the voltage-blocking-layer on the buffer layer.

A heterojunction bipolar transistor includes a collector layer, a base layer, an emitter layer, and a semiconductor layer that are laminated in this order, wherein the emitter layer includes a first region having an upper surface on which the semiconductor layer is laminated, and a second region being adjacent to the first region and having an upper surface that is exposed, and the first and second regions of the emitter layer have higher doping concentrations in portions near the upper surfaces than in portions near an interface between the emitter layer and the base layer.

Various embodiments of the present disclosure are directed towards a method for forming a bipolar junction transistor (BJT). A dielectric film is deposited over a substrate and comprises a lower dielectric layer, an upper dielectric layer, and an intermediate dielectric layer between the lower and upper dielectric layers. A first semiconductor layer is deposited over the dielectric film and is subsequently patterned to form an opening exposing the dielectric film. A first etch is performed into the upper dielectric layer through the opening to extend the opening to the intermediate dielectric layer. Further, the first etch stops on the intermediate dielectric layer and laterally undercuts the first semiconductor layer. Additional etches are performed to extend the opening to the substrate. A lower base structure and an emitter are formed stacked in and filling the opening, and the first semiconductor layer is patterned to form an upper base structure.

A bipolar transistor includes a stack of an emitter, a base, and a collector. The base is structured to have a comb shape including fingers oriented in a plane orthogonal to a stacking direction of the stack.