A semiconductor device or circuit includes a vertical bipolar junction transistor (vBJT) and a vertical filed effect transistor (vFET). The vBJT collector is electrically and/or physically connected to an adjacent vFET source. For example, a vBJT collector and a vFET source may be integrated upon a same semiconductor material substrate or layer. The vFET provides negative feedback for the collector-base voltage and the vBJT emitter and collector allow for low transit times.

An integrated circuit includes a bipolar transistor, e.g. a back-ballasted NPN, that can conduct laterally and vertically. At a low voltage breakdown and low current conduction occur laterally near a substrate surface, while at a higher voltage vertical conduction occurs in a more highly-doped channel below the surface. A relatively high-resistance region at the surface has a low doping level to guide the conduction deeper into the collector.

A semiconductor device includes a semiconductor substrate, a first semiconductor region of a first semiconductor type, formed within the semiconductor substrate, wherein the first semiconductor region includes a first doped region formed in a lower portion of the first semiconductor region and a second doped region formed over the first doped region in an upper portion of the first semiconductor region. A defect layer having an upper surface formed in an upper portion of the first doped region. A second semiconductor region of a second semiconductor type is formed over the first semiconductor region.

A semiconductor device or circuit includes a vertical bipolar junction transistor (vBJT) and a vertical filed effect transistor (vFET). The vBJT collector is electrically and/or physically connected to an adjacent vFET source. For example, a vBJT collector and a vFET source may be integrated upon a same semiconductor material substrate or layer. The vFET provides negative feedback for the collector-base voltage and the vBJT emitter and collector allow for low transit times.

A method includes providing a semiconductor structure having an active region and an isolation structure adjacent to the active region, the active region having source and drain regions sandwiching a channel region for a transistor, the semiconductor structure further having a gate structure over the channel region. The method further includes etching a trench in one of the source and drain regions, wherein the trench exposes a portion of a sidewall of the isolation structure, epitaxially growing a first semiconductor layer in the trench, epitaxially growing a second semiconductor layer over the first semiconductor layer, changing a crystalline facet orientation of a portion of a top surface of the second semiconductor layer by an etching process, and epitaxially growing a third semiconductor layer over the second semiconductor layer after the changing of the crystalline facet orientation.

A bipolar junction transistor includes an extrinsic collector region buried in a semiconductor substrate under an intrinsic collector region. Carbon-containing passivating regions are provided to delimit the intrinsic collector region. An insulating layer on the intrinsic collector region includes an opening within which an extrinsic base region is provided. A semiconductor layer overlies the insulating layer, is in contact with the extrinsic base region, and includes an opening with insulated sidewalls. The collector region of the transistor is provided between the insulated sidewalls.

Methods of according to the present disclosure can include: providing a substrate including: a first semiconductor region, a second semiconductor region, and a trench isolation (TI) laterally between the first and second semiconductor regions; forming a seed layer on the TI and the second semiconductor region of the substrate, leaving the first semiconductor region of the substrate exposed; forming an epitaxial layer on the substrate and the seed layer, wherein the epitaxial layer includes: a first semiconductor base material positioned above the first semiconductor region of the substrate, and an extrinsic base region positioned above the seed layer; forming an opening within the extrinsic base material and the seed layer to expose an upper surface of the second semiconductor region; and forming a second semiconductor base material in the opening.

Aspects of the disclosure provide an integrated circuit (IC) structure with a bipolar transistor stack within a substrate. The bipolar transistor stack may include: a collector, a base on the collector, and an emitter on a first portion of the base. A horizontal width of the emitter is less than a horizontal width of the base, and an upper surface of the emitter is substantially coplanar with an upper surface of the substrate. An extrinsic base structure is on a second portion of the base of the bipolar transistor stack, and horizontally adjacent the emitter. The extrinsic base structure includes an upper surface above the upper surface of the substrate.

Various particular embodiments include an integrated circuit (IC) structure including: a stack region; and a silicon substrate underlying and contacting the stack region, the silicon substrate including: a silicon region including a doped subcollector region; a set of isolation regions overlying the silicon region; a base region between the set of isolation regions and below the stack region, the base region including an intrinsic base contacting the stack region, an extrinsic base contacting the intrinsic base and the stack region, and an amorphized extrinsic base contact region contacting the extrinsic base; a collector region between the set of isolation regions; an undercut collector-base region between the set of isolation regions and below the base region; and a collector contact region contacting the collector region under the intrinsic base and the collector-base region via the doped subcollector region.

The present disclosure relates to semiconductor structures and, more particularly, to virtual bulk in semiconductor on insulator technology and methods of manufacture. The structure includes a heterojunction bipolar transistor formed on a semiconductor on insulator (SOI) wafer with a doped sub-collector material in a buried insulator region under a semiconductor substrate of the SOI wafer.