Embodiments of the disclosure provide an integrated circuit (IC) structure, including a semiconductor-based isolation structure on a substrate. A shallow trench isolation (STI) structure may be positioned on the semiconductor-based isolation structure. An active semiconductor region is on the substrate and adjacent each of the semiconductor-based isolation structure and the STI structure. The active semiconductor region includes a doped semiconductor material. At least one device on the active semiconductor region may be horizontally distal to the STI structure.

Embodiments of the disclosure provide an integrated circuit (IC) structure, including a semiconductor-based isolation structure on a substrate. A shallow trench isolation (STI) structure may be positioned on the semiconductor-based isolation structure. An active semiconductor region is on the substrate and adjacent each of the semiconductor-based isolation structure and the STI structure. The active semiconductor region includes a doped semiconductor material. At least one device on the active semiconductor region may be horizontally distal to the STI structure.

A semiconductor die includes a structural body that has a power region and a peripheral region surrounding the power region. At least one power device is positioned in the power region. Trench-insulation means extend in the structural body starting from the front side towards the back side along a first direction, adapted to hinder conduction of heat from the power region towards the peripheral region along a second direction orthogonal to the first direction. The trench-insulation means have an extension, in the second direction, greater than the thickness of the structural body along the first direction.

A semiconductor die includes a structural body that has a power region and a peripheral region surrounding the power region. At least one power device is positioned in the power region. Trench-insulation means extend in the structural body starting from the front side towards the back side along a first direction, adapted to hinder conduction of heat from the power region towards the peripheral region along a second direction orthogonal to the first direction. The trench-insulation means have an extension, in the second direction, greater than the thickness of the structural body along the first direction.

A semiconductor device and a method of fabricating a semiconductor device, the device including a semiconductor substrate that includes a trench defining an active region; a buried dielectric pattern in the trench; a silicon oxide layer between the buried dielectric pattern and an inner wall of the trench; and a polycrystalline silicon layer between the silicon oxide layer and the inner wall of the trench, wherein the polycrystalline silicon layer has a first surface in contact with the semiconductor substrate and a second surface in contact with the silicon oxide layer, and wherein the second surface includes a plurality of silicon grains that are uniformly distributed.

A semiconductor device and a method of fabricating a semiconductor device, the device including a semiconductor substrate that includes a trench defining an active region; a buried dielectric pattern in the trench; a silicon oxide layer between the buried dielectric pattern and an inner wall of the trench; and a polycrystalline silicon layer between the silicon oxide layer and the inner wall of the trench, wherein the polycrystalline silicon layer has a first surface in contact with the semiconductor substrate and a second surface in contact with the silicon oxide layer, and wherein the second surface includes a plurality of silicon grains that are uniformly distributed.

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.

Embodiments of the disclosure provide a bipolar transistor structure with a collector on a polycrystalline isolation layer. A polycrystalline isolation layer may be on a substrate, and a collector layer may be on the polycrystalline isolation layer. The collector layer has a first doping type and includes a polycrystalline semiconductor. A base layer is on the collector layer and has a second doping type opposite the first doping type. An emitter layer is on the base layer and has the first doping type. A material composition of the doped collector region is different from a material composition of the base layer.

Embodiments of the disclosure provide a bipolar transistor structure with a collector on a polycrystalline isolation layer. A polycrystalline isolation layer may be on a substrate, and a collector layer may be on the polycrystalline isolation layer. The collector layer has a first doping type and includes a polycrystalline semiconductor. A base layer is on the collector layer and has a second doping type opposite the first doping type. An emitter layer is on the base layer and has the first doping type. A material composition of the doped collector region is different from a material composition of the base layer.

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.