A circuit includes at least one bipolar transistor and at least one variable capacitance diode. The circuit is fabricated using a method whereby the bipolar transistor and variable capacitance diode are jointly produced on a common substrate.

Gate-all-around integrated circuit structures including varactors are described. For example, an integrated circuit structure includes a varactor structure on a semiconductor substrate. The varactor structure includes a plurality of discrete vertical arrangements of horizontal nanowires. A plurality of gate stacks is over and surrounding corresponding ones of the plurality of discrete vertical arrangements of horizontal nanowires. The integrated circuit structure also includes a tap structure adjacent to the varactor structure on the semiconductor substrate. The tap structure includes a plurality of merged vertical arrangements of horizontal nanowires. A plurality of semiconductor structures is over and surrounding corresponding ones of the plurality of merged vertical arrangements of horizontal nanowires.

An image sensing device is provided to include a pixel region and a peripheral region located outside of the pixel region. The peripheral region includes logic circuits located to receive a pixel signals from the pixel region and configured to process the pixel signals and a capacitor located adjacent to the logic circuits. The capacitor includes an active region, a recessed structure, and a first junction. The active region includes a first impurity region and a second impurity region formed over the first impurity region. The recessed structure is at least partly disposed in the active region and including a first portion disposed in the active region and including a conductive material and a second portion surrounding the first portion and including an insulation material. The first junction is formed in the active region and spaced apart from the recessed structure by a predetermined distance.

A passive tunable integrated circuit (PTIC) having an electro-static discharge (ESD) protection circuit is disclosed. The ESD protection circuit includes at least one spark gap that has a breakdown voltage determined by design parameters. The at least one spark gaps are configured to route signals above a breakdown voltage to ground in order to protect a variable capacitor. The design parameters can be based on a material (Barium Strontium Titanate), a structure, and a fabrication process of the PTIC and further based on expected ESD signals for a mobile device application.

A semiconductor device includes a substrate and an isolation feature. The isolation feature includes a first portion in the substrate, and a second portion extending along a top surface of the substrate, wherein a bottom surface of the second portion is below the top surface of the substrate. The semiconductor device further includes a gate structure over the substrate, wherein the gate structure extends along a top surface of the second portion of the isolation feature.

Gate-all-around integrated circuit structures including varactors are described. For example, an integrated circuit structure includes a varactor structure on a semiconductor substrate. The varactor structure includes a plurality of discrete vertical arrangements of horizontal nanowires. A plurality of gate stacks is over and surrounding corresponding ones of the plurality of discrete vertical arrangements of horizontal nanowires. The integrated circuit structure also includes a tap structure adjacent to the varactor structure on the semiconductor substrate. The tap structure includes a plurality of merged vertical arrangements of horizontal nanowires. A plurality of semiconductor structures is over and surrounding corresponding ones of the plurality of merged vertical arrangements of horizontal nanowires.

A capacitor structure includes a semiconductor substrate, a first vertical diffusion plate in the semiconductor substrate, a first STI structure in the semiconductor substrate and surrounding the first vertical diffusion plate, a second vertical diffusion plate in the semiconductor substrate and surrounding the first STI structure, and an ion well in the semiconductor substrate. The ion well is disposed directly under the first vertical diffusion plate, the first STI structure and the second vertical diffusion plate. The second vertical diffusion plate is electrically coupled to an anode of the capacitor structure. The first vertical diffusion plate is electrically coupled to a cathode of the capacitor structure.

A varactor structure includes a substrate. A first and second gate structure are disposed on the substrate. The first and second gate structures each include a base portion and a plurality of line portions connected thereto. The line portions of each of the first and second gate structures is alternately arranged. A meander diffusion region is formed in the substrate and surrounds the line portions. A first set of contact plugs is planned with at least two columns or rows and disposed on the base portions of the first and second gate structures. A second set of contact plugs is planned with at least two columns or rows and disposed on the meander diffusion region. A first conductive layer is disposed on a top end of the first set of contact plugs. A second conductive layer is disposed on a top end of the second set of contact plugs.

Various embodiments of the present disclosure are directed towards a method for forming a varactor comprising a reduced surface field (RESURF) region. The method includes forming a drift region having a first doping type within a substrate. A RESURF region having a second doping type is formed within the substrate such that the RESURF region is below the drift region. A gate structure is formed on the substrate. A pair of contact regions is formed within the substrate on opposing sides of the gate structure. The contact regions respectively abut the drift region and have the first doping type, and wherein the first doping type is opposite the second doping type.

Various embodiments of the present disclosure are directed towards a varactor comprising a reduced surface field (RESURF) region. In some embodiments, the varactor includes a drift region, a gate structure, a pair of contact regions, and a RESURF region. The drift region is within a substrate and has a first doping type. The gate structure overlies the drift region. The contact regions are within the substrate and overlie the drift region. Further, the contact regions have the first doping type. The gate structure is laterally sandwiched between the contact regions. The RESURF region is in the substrate, below the drift region, and has a second doping type. The second doping type is opposite the first doping type. The RESURF region aids in depleting the drift region under the gate structure, which decreases the minimum capacitance of the varactor and increases the tuning range of the varactor.