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.

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.

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.

A heterojunction bipolar transistor includes a collector layer, a base layer, and an emitter layer that are stacked on a substrate. The collector layer includes a graded semiconductor layer in which an electron affinity increases from a side closer to the base layer toward a side farther from the base layer. An electron affinity of the base layer at an interface closer to the collector layer is equal to an electron affinity of the graded semiconductor layer at an interface closer to the base layer.

A first sub-collector layer functions as an inflow path of a collector current that flows in a collector layer of a heterojunction bipolar transistor. A collector ballast resistor layer having a lower doping concentration than the first sub-collector layer is disposed between the collector layer and the first sub-collector layer.

A semiconductor device that includes a bipolar transistor, wherein a third opening, through which a pillar bump and a second wiring line, which is electrically connected to an emitter layer, contact each other, is shifted in a longitudinal direction of the emitter layer away from a position at which the third opening would be directly above the emitter layer. The third opening is arranged, with respect to the emitter layer, such that an end portion of the emitter layer in the longitudinal direction of the emitter layer and the edge of the opening of the third opening are substantially aligned with each other.

Aspects generally relate to a heterojunction bipolar transistor (HBT), and method of manufacturing the same. The HBT including an emitter a first, a first side of a base coupled to a second side of the emitter opposite the first side of the emitter. A collector coupled to the base on a second side of the base opposite the emitter, wherein an area of a junction between the base and the collector is less than or equal to an area of a junction between the base and the emitter. A dielectric coupled to the collector. A first conductive base contact coupled to the base and adjacent to the collector and extending over a base-collector junction, the conductive base contact operative as a field plate.

A piezo-junction device may be provided. The piezo-junction device comprises a piezoelectric element comprising two electrodes and piezoelectric material in-between, and a semiconductor junction device adjacent to the piezoelectric element such that one of the two electrodes of the piezoelectric element is in contact with the semiconductor junction device connecting the semiconductor junction device and the piezoelectric element electrically in series. Thereby, the semiconductor junction device and the piezoelectric element are together positioned in a fixed mechanical clamp such that the piezoelectric element with an applied electrical field applies strain to the semiconductor junction device causing a change in Fermi levels of the semiconductor junction device.

A method of forming a bipolar transistor with a vertical collector contact requires providing a transistor comprising a plurality of epitaxial semiconductor layers on a first substrate, and providing a host substrate. A metal collector contact is patterned on the top surface of the host substrate, and the plurality of epitaxial semiconductor layers is transferred from the first substrate onto the metal collector contact on the host substrate. The first substrate is suitably the growth substrate for the plurality of epitaxial semiconductor layers. The host substrate preferably has a higher thermal conductivity than does the first substrate, which improves the heat dissipation characteristics of the transistor and allows it to operate at higher power densities. A plurality of transistors may be transferred onto a common host substrate to form a multi-finger transistor.

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.