Device structures, fabrication methods, and design structures for a bipolar junction transistor. A trench isolation region is formed in a substrate. The trench isolation region is coextensive with a collector in the substrate. A base layer is formed on the collector and on a first portion of the trench isolation region. A dielectric layer is formed on the base layer and on a second portion of the trench isolation region peripheral to the base layer. After the dielectric layer is formed, the trench isolation region is at least partially removed to define an air gap beneath the dielectric layer and the base 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.

A process for making a transistor that includes removing a sacrificial material under a base layer that includes dopants for an intrinsic base of a transistor. After the removal of the sacrificial layer to form a cavity directly under the base layer, a semiconductor material is formed in the cavity. The semiconductor layer includes dopants for a current electrode of the transistor that is located directly under the intrinsic base of the transistor.

Device structures for a bipolar junction transistor. A layer is formed on a top surface of a substrate. A trench is formed in the layer and has a plurality of sidewalls with a width between an opposite pair of the sidewalls that varies with increasing distance from the top surface of the substrate. A collector pedestal of the bipolar junction transistor is formed in the trench.

The present invention is directed to semiconductor processes and devices. More specifically, embodiments of the present invention provide a shaped cavity that this later to be filled with SiGe material. The shape cavity comprises convex regions interfacing the substrate. There are other embodiments as well.

Disclosed are a structure for providing electrical isolation in a semiconductor substrate and an associated method for the structure's fabrication. The structure includes a deep trench isolation loop having a first depth disposed in the semiconductor substrate. A dielectric material is disposed in the deep trench isolation loop and one or more through silicon vias (TSVs), having a second depth, are disposed in the semiconductor substrate and within a perimeter of the deep trench isolation loop. A portion of the semiconductor substrate surrounding the deep trench isolation loop may be doped. A metallic filler may be disposed within the one or more TSVs and the metallic filler may be in direct electrical contact with the semiconductor substrate.

A semiconductor device having a stressor is provided. A first trench and a second trench spaced apart from each other are formed in a substrate. A channel area is defined between the first trench and the second trench. A gate dielectric layer is formed on the channel area. A gate electrode is formed on the gate dielectric layer. The stressor includes a plurality of semiconductor layers formed in the first trench and the second trench and a plurality of interlayers formed between the semiconductor layers. Sidewalls of the first trench and the second trench are v-shaped (e.g., have a < or > shape).

A SiGe HBT has an inverted heterojunction structure, where the emitter layer is formed prior to the base layer and the collector layer. The frequency performance of the SiGe HBT is significantly improved through a better thermal process budget for the base profile, essential for higher cut-off frequency (f.sub.T) and a minimal collector-base area for a reduced parasitic capacitance, essential for higher maximum oscillation frequency (f.sub.max). This inverted heterojunction structure can be fabricated by using ALE processes to form an emitter on a preformed epitaxial silicide, a base over the emitter and a collector over the base.

A semiconductor device comprising a bipolar transistor and a method of making the same. A power amplifier including a bipolar transistor. The bipolar transistor includes a collector including a laterally extending drift region. The also includes a base located above the collector. The bipolar transistor further includes an emitter located above the base. The bipolar transistor also includes a doped region having a conductivity type that is different to that of the collector. The doped region extends laterally beneath the collector to form a junction at a region of contact between the doped region and the collector. The doped region has a non-uniform lateral doping profile. A doping level of the doped region is highest in a part of the doped region closest to a collector-base junction of the bipolar transistor.

Techniques are disclosed for converting a strain-inducing semiconductor buffer layer into an electrical insulator at one or more locations of the buffer layer, thereby allowing an above device layer to have a number of benefits, which in some embodiments include those that arise from being grown on a strain-inducing buffer and having a buried electrical insulator layer. For instance, having a buried electrical insulator layer (initially used as a strain-inducing buffer during fabrication of the above active device layer) between the Fin and substrate of a non-planar integrated transistor circuit may simultaneously enable a low-doped Fin with high mobility, desirable device electrostatics and elimination or otherwise reduction of substrate junction leakage. Also, the presence of such an electrical insulator under the source and drain regions may further significantly reduce junction leakage. In some embodiments, substantially the entire buffer layer is converted to an electrical insulator.