The present disclosure relates to semiconductor structures and, more particularly, to bipolar transistors and methods of manufacture. The structure includes: an intrinsic base region; an emitter region above the intrinsic base region; a collector region under the intrinsic base region; and an extrinsic base region comprising metal material, and which surrounds the intrinsic base region and the emitter region.

A vertical bipolar junction transistor may include an intrinsic base epitaxially grown on a first emitter or collector, the intrinsic base being compositionally graded, a second collector or emitter formed on the intrinsic base, and an extrinsic base formed all-around the intrinsic base. The extrinsic base may be isolated from the first emitter or collector by a first spacer. The extrinsic base may be isolated from the second collector or emitter by a second spacer. The extrinsic base may have a larger bandgap than the intrinsic base. The intrinsic base may be doped with a p-type dopant, and the first emitter or collector, and the second collector or emitter may be doped with an n-type dopant. The first emitter or collector, the intrinsic base, and the second collector or emitter may be made of a III-V semiconductor material.

A semiconductor die includes a transistor with an emitter, base, and collector. The base includes an intrinsic base that is located in monocrystalline semiconductor material grown in an opening of a first semiconductor layer. A second semiconductor layer is located above the first semiconductor layer and includes a monocrystalline portion. In some embodiments, an opening was formed in the second semiconductor layer wherein a portion of the underlying first semiconductor layer was etched to form a cavity in which a monocrystalline intrinsic base was grown.

A bipolar transistor comprising a subcollector layer, and a collector layer on the subcollector layer. The collector layer includes a plurality of doped layers. The plurality of doped layers includes a first doped layer that has a highest impurity concentration thereamong and is on a side of or in contact with the subcollector layer. Also, the first doped layer includes a portion that extends beyond at least one edge of the plurality of doped layers in a cross-sectional view.

An electrostatic discharge (ESD) protection circuit (FIG. 3C) is disclosed. The circuit includes a bipolar transistor (304) having a base, collector, and emitter. Each of a plurality of diodes (308-316) has a first terminal coupled to the base and a second terminal coupled to the collector. The collector is connected to a first terminal (V+). The emitter is connected to a first power supply terminal (V−).

An electrical device includes a counterdoped heterojunction selected from a group consisting of a pn junction or a p-i-n junction. The counterdoped junction includes a first semiconductor doped with one or more n-type primary dopant species and a second semiconductor doped with one or more p-type primary dopant species. The device also includes a first counterdoped component selected from a group consisting of the first semiconductor and the second semiconductor. The first counterdoped component is counterdoped with one or more counterdopant species that have a polarity opposite to the polarity of the primary dopant included in the first counterdoped component. Additionally, a level of the n-type primary dopant, p-type primary dopant, and the one or more counterdopant is selected to the counterdoped heterojunction provides amplification by a phonon assisted mechanism and the amplification has an onset voltage less than 1 V.

The present disclosure relates to semiconductor structures and, more particularly, to bipolar transistors and methods of manufacture. The structure includes: an extrinsic base region comprising at least a plurality of gate structures on a semiconductor structure; an emitter between the plurality of gate structures; an intrinsic base region between the plurality of gate structures; and a collector region under the plurality of gate structure in the semiconductor material.

A bipolar junction transistor (BJT) may include a substrate defining a collector region therein. A first superlattice may be on the substrate including a plurality of stacked groups of first layers, with each group of first layers including a first plurality of stacked base semiconductor monolayers defining a first base semiconductor portion, and at least one first non-semiconductor monolayer constrained within a crystal lattice of adjacent first base semiconductor portions. Furthermore, a base may be on the first superlattice, and a second superlattice may be on the base including a second plurality of stacked groups of second layers, with each group of second layers including a plurality of stacked base semiconductor monolayers defining a second base semiconductor portion, and at least one second non-semiconductor monolayer constrained within a crystal lattice of adjacent second base semiconductor portions. An emitter may be on the second superlattice.

A semiconductor memory cell includes a floating body region configured to be charged to a level indicative of a state of the memory cell selected from at least first and second states. A first region of the memory cell is in electrical contact with the floating body region. A second region of the memory cell is spaced apart from the first region and is also in electrical contact with the floating body region. A gate is positioned between the first and second regions. A back-bias region is configured to generate impact ionization when the memory cell is in one of the first and second states, and the back-bias region is configured so as not to generate impact ionization when the memory cell is in the other of the first and second states.

A plug electrode is subject to etch back to remain in a contact hole and expose a barrier metal on a top surface of an interlayer insulating film. The barrier metal is subject to etch back, exposing the top surface of the interlayer insulating film. Remaining element structures are formed. After lifetime is controlled by irradiation of helium or an electron beam, hydrogen annealing is performed. During the hydrogen annealing, the barrier metal is not present on the interlayer insulating film covering a gate electrode, enabling hydrogen atoms to reach a mesa part, whereby lattice defects generated in the mesa part by the irradiation of helium or an electron beam are recovered, recovering the gate threshold voltage. Thus, predetermined characteristics of a semiconductor device having a structure where a plug electrode is provided in a contact hole, via barrier metal are easily and stably obtained when lifetime control is performed.