The present disclosure generally relates to semiconductor processing for forming an emitter layer in a bipolar junction transistor (BJT). In an example, a BJT includes a collector, a base on the collector, and an emitter layer on the base. The emitter layer includes a first emitter sub-layer and a second emitter sub-layer over the first emitter sub-layer. The first emitter sub-layer includes boron and carbon. A concentration of carbon is uniform throughout the first emitter sub-layer. The second emitter sub-layer includes boron. A concentration of boron in the second emitter sub-layer is greater than a concentration of boron in the first emitter sub-layer.

Provided are a heterojunction bipolar transistor (HBT), a radio frequency module, and a communication device. The HBT includes: a semiconductor stack, an emitter metal, a first passivation layer, a first metal, and a dielectric layer. The semiconductor stack has first surface and second surfaces, and includes an emitter step and a base step having a step side surface. The emitter metal is disposed on the emitter step. The first passivation layer covers at least a side surface of the emitter metal and extends to cover a portion of the first surface exposed outside the emitter step, the step side surface, and a portion of the first surface exposed outside the base step. The first metal includes a base metal, which is at least partially disposed on the first surface, and is adjacent to the emitter step and spaced apart from the emitter step.

The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors and methods of manufacture. The structure includes: a semiconductor substrate; a collector region over the semiconductor substrate; an intrinsic base over the collector region; an electrically insulating heat dissipative material at a junction of the collector region and the intrinsic base; an extrinsic base over the intrinsic base; and an emitter region adjacent to the extrinsic base.

The disclosure provides bipolar transistor structures with a semiconductor film, and related methods. A structure of the disclosure includes an intrinsic base on a collector. The collector has a first doping type. A semiconductor film is on the intrinsic base and horizontally surrounds the intrinsic base. The semiconductor film horizontally encapsulates the intrinsic base. An emitter having the first doping type is on a first portion of the semiconductor film. An extrinsic base having a second doping type is on a second portion of the semiconductor film.

The present disclosure relates to semiconductor structures and, more particularly, to devices with airgap structures and methods of manufacture. The structure includes: a semiconductor substrate with a trap-rich region; one or more airgap structures within the semiconductor substrate; at least one deep trench isolation structure laterally surrounding the one or more airgap structures and extending into the semiconductor substrate; and a device over the one or more airgap structures.

The present disclosure relates to semiconductor structures and, more particularly, to a heterojunction bipolar transistor and methods of manufacture. The structure includes: a plurality of active devices in a layout, the plurality of active devices comprising semiconductor material with a first dopant type; a protective film; and a fill shape covering the protective film and comprising the semiconductor material with the first dopant type.

The disclosure provides a structure base portions having different germanium concentrations, and related methods. A structure of the disclosure includes a base region including a first portion on a first emitter/collector (E/C) terminal and including germanium (Ge). A Ge concentration in the first portion varies with respect to distance from the first E/C terminal. A second portion is on the first portion and includes Ge. A third portion is between the second portion and a second E/C terminal and includes Ge. A Ge concentration in the third portion varies with respect to distance between the second portion and the second E/C terminal.

A semiconductor device includes an active region, including: a semiconductor layer, having a first surface, including a collector layer, a base layer and an emitter layer sequentially stacked, and the first surface being a surface of the emitter layer facing away from the base layer; an emitter mesa and an emitter electrode sequentially disposed on the emitter layer; a first dielectric layer, covering a top surface of the emitter electrode, extending along a side surface of the emitter electrode to cover part of the first surface exposed outside the emitter electrode, and defining a first opening; a second dielectric layer, covering the first dielectric layer, and defining a second opening connected to the first opening; and a base electrode, connected to the base layer through the first opening and the second opening, and extending to cover at least part of the second dielectric layer adjacent to the second opening.

A semiconductor device includes an active region, including: a semiconductor layer, having a first surface, including a collector layer, a base layer and an emitter layer sequentially stacked, and the first surface being a surface of the emitter layer facing away from the base layer; an emitter mesa and an emitter electrode sequentially disposed on the emitter layer; a first dielectric layer, covering a top surface of the emitter electrode, extending along a side surface of the emitter electrode to cover part of the first surface exposed outside the emitter electrode, and defining a first opening; a second dielectric layer, covering the first dielectric layer, and defining a second opening connected to the first opening; and a base electrode, connected to the base layer through the first opening and the second opening, and extending to cover at least part of the second dielectric layer adjacent to the second opening.

A nitride semiconductor device capable of enhancing device characteristics is provided. The nitride semiconductor device may comprise a polarized doped layer being a ternary nitride semiconductor and having a first conductivity type characteristic due to its compositional gradient in a thickness direction. The nitride semiconductor device may comprise a first layer of a nitride semiconductor of a second conductivity type disposed on a bottom surface of the polarized doped layer. The nitride semiconductor device may comprise a second layer of a nitride semiconductor of the second conductivity type disposed on a top surface of the polarized doped layer. The nitride semiconductor device may comprise: a first electrode disposed in electrical contact with the first layer; a second electrode disposed in electrical contact with the second layer; and a third electrode disposed in electrical contact with the polarized doped layer.