Abstract: Device structures for a field-effect transistor and methods of forming a device structure for a field-effect transistor. A trench isolation region is formed in a substrate, and surrounds a semiconductor body. An undercut cavity region is also formed in the substrate. The undercut cavity region extends laterally beneath the semiconductor body and defines a body pedestal as a section of the substrate that is arranged in vertical alignment with the semiconductor body.

Abstract: Structures with altered crystallinity beneath semiconductor devices and methods associated with forming such structures. Trench isolation regions surround an active device region composed of a single-crystal semiconductor material. A first non-single-crystal layer is arranged beneath the trench isolation regions and the active device region. A second non-single-crystal layer is arranged beneath the trench isolation regions and the active device region. The first non-single-crystal layer is arranged between the second non-single-crystal layer and the active device region.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to a transistor with an embedded isolation layer in a bulk substrate and methods of manufacture. The structure includes: a bulk substrate; an isolation layer embedded within the bulk substrate and below a top surface of the bulk substrate; a deep trench isolation structure extending through the bulk substrate and contacting the embedded isolation layer; and a gate structure over the top surface of the bulk substrate and vertically spaced away from the embedded isolation layer, the deep trench isolation structure and the embedded isolation layer defining an active area of the gate structure in the bulk substrate.

Abstract: Photonics structures including an optical component and methods of fabricating a photonics structure including an optical component. The photonics structure includes an optical component, a substrate having a cavity and a dielectric material in the cavity, and a dielectric layer positioned in a vertical direction between the optical component and the cavity. The optical component is positioned in a lateral direction to overlap with the cavity in the substrate.

Abstract: Structures including an edge coupler, and methods of fabricating a structure that includes an edge coupler. The structure includes an edge coupler having a waveguide core with an end surface and a longitudinal axis. The end surface defines a plane tilted in a first direction at a first acute angle relative to the longitudinal axis and tilted in a second direction at a second acute angle relative to the longitudinal axis. The second direction differs from the first direction.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to vertically stacked field effect transistors and methods of manufacture. The structure includes: at least one lower gate structure on a bottom of a trench formed in substrate material; insulator material partially filling trench and over the at least one lower gate structure; an epitaxial material on the insulator material and isolated from sidewalls of the trench; and at least one upper gate structure stacked vertically above the at least one lower gate structure and located on the epitaxial material.

Abstract: Structures including an edge coupler, and methods of fabricating a structure that includes an edge coupler. The structure includes an edge coupler having a waveguide core with an end surface and a longitudinal axis. The end surface defines a plane tilted in a first direction at a first acute angle relative to the longitudinal axis and tilted in a second direction at a second acute angle relative to the longitudinal axis. The second direction differs from the first direction.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors (HBTs) with a buried trap rich region and methods of manufacture. The structure includes: a trap rich isolation region embedded within the bulk substrate; and a heterojunction bipolar transistor above the trap rich isolation region, with its sub-collector region separated by the trap rich isolation region by a layer of the bulk substrate.

Abstract: Structures including an edge coupler and methods of fabricating a structure including an edge coupler. The structure includes an edge coupler having a longitudinal axis, a first ring resonator, and a second ring resonator. The first ring resonator has a first center point that is spaced from the longitudinal axis of the edge coupler by a first perpendicular distance. The second ring resonator has a second center point that is spaced from the longitudinal axis of the edge coupler by a second perpendicular distance.

Abstract: Embodiments of the disclosure provide a method, including forming a shallow trench isolation (STI) in a substrate. The method further includes doping the substrate with a noble dopant, thereby forming a disordered crystallographic layer under the STI. The method also includes converting the disordered crystallographic layer to a doped buried polysilicon layer under the STI and a high resistivity (HR) polysilicon layer under the doped buried polysilicon layer. The method includes forming a pair of contacts operatively coupled in a spaced manner to the doped buried polysilicon layer.

Abstract: An integrated circuit (IC) structure, a switch and related method, are disclosed. The IC structure includes an active device, e.g., a switch, over a bulk semiconductor substrate, and an isolation structure under the active device in the bulk semiconductor substrate. The isolation structure may include a trench isolation adjacent the active device in the bulk semiconductor substrate, a dielectric layer laterally adjacent the trench isolation and over the active device, and a porous semiconductor layer in the bulk semiconductor substrate under the dielectric layer laterally adjacent the trench isolation. The IC structure employs a lower cost, low resistivity bulk semiconductor substrate rather than a semiconductor-on-insulator (SOI) substrate, yet it has better performance characteristics for RF switches than an SOI substrate.

Abstract: A structure includes a field effect transistor (FET) stack including a plurality of transistors over a buried insulator layer. A polysilicon isolation region is in a substrate below the FET stack and the buried insulator layer. A resistor network is in the polysilicon isolation region, the resistor network having a different resistivity than the polysilicon isolation region. The resistor network may include a resistive wire having a first width and a resistive pad within the resistive wire under each FET in the FET stack. Each resistive pad has a second width larger than the first width of the resistive wire. A length of the resistive wire is different aside each resistive pad to adjust a threshold voltage of an adjacent FET in the FET stack to a predetermined value to compensate for non-linear voltage distribution between an input and an output of the FET stack.

Abstract: An integrated circuit (IC) structure includes an active device over a bulk semiconductor substrate, and an isolation structure around the active device in the bulk semiconductor substrate. The active device includes a semiconductor layer having a center region, a first end region laterally spaced from the center region by a first trench isolation, a second end region laterally spaced from the center region by a second trench isolation, a gate over the center region, and a source/drain region in each of the first and second end regions. The isolation structure includes: a polycrystalline isolation layer under the active device, a third trench isolation around the active device, and a porous semiconductor layer between the first trench isolation and the polycrystalline isolation layer and between the second trench isolation and the polycrystalline isolation layer.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to a photodiode with an integrated, light focusing elements and methods of manufacture. The structure includes: a trench photodiode comprising a domed structure; and a doped material on the domed structure, the doped material having a concave underside surface.

Abstract: A structure provides a polysilicon resistor under a shallow trench isolation (STI). The structure includes the STI, a resistor in the form of a doped buried polysilicon layer under the STI, and a high resistivity (HR) polysilicon layer under the doped buried polysilicon layer. The structure also includes a pair of contacts operatively coupled in a spaced manner to the doped buried polysilicon layer. A related method is also disclosed.

Abstract: Structures for a field-effect transistor and methods of forming a structure for a field-effect transistor. The structure includes a semiconductor substrate having a first trench, and a trench isolation region positioned in the first trench. The trench isolation region contains a dielectric material, the trench isolation region includes a second trench surrounded by the dielectric material, and the trench isolation region includes openings that penetrate through the dielectric material. A semiconductor layer is positioned in the second trench of the trench isolation region. The semiconductor layer contains a single-crystal semiconductor material.

Abstract: Structures for a polarization rotator and methods of fabricating a structure for a polarization rotator. The structure includes a substrate, a first waveguide core over the substrate, and a second waveguide core over the substrate. The second waveguide core is positioned proximate to the section of the first waveguide core. The second waveguide core is comprised of a material having a refractive index that is reversibly variable in response to a stimulus.

Abstract: A “lab on a chip” includes an optofluidic sensor and components to analyze signals from the optofluidic sensor. The optofluidic sensor includes a substrate, a channel at least partially defined by a portion of a layer of first material on the substrate, input and output fluid reservoirs in fluid communication with the channel, at least a first radiation source coupled to the substrate adapted to generate radiation in a direction toward the channel, and at least one photodiode positioned adjacent and below the channel.

Abstract: Structures for a transistor including regions for landing gate contacts and methods of forming a structure for a transistor that includes regions for landing gate contacts. The structure includes a field-effect transistor having a source region, a gate region, a gate with a sidewall, and a gate extension with a section adjoined to the sidewall. The structure further includes a dielectric layer over the field-effect transistor, and a gate contact positioned in the dielectric layer to land on at least the section of the gate extension.

Abstract: Processing forms an integrated circuit structure having first and second layers on opposite sides of an insulator, and an interconnect structure extending through the insulator between the first layer and the second layer. The interconnect structure is formed in an opening extending through the insulator between the first layer and the second layer and has an electrical conductor in the opening extending between the first layer and the second layer and a thermally conductive electrical insulator liner along sidewalls of the opening extending between the first layer and the second layer. The electrical conductor is positioned to conduct electrical signals between the first layer and the second layer, and the thermally conductive electrical insulator liner is positioned to transfer heat between the first layer and the second layer.