Abstract: Method for selective fabrication of high capacitance density areas in a low dielectric constant material and related structure are disclosed. In one embodiment, a first area of a dielectric layer is covered, for example with photoresist, while a second area of the dielectric layer is exposed to a dielectric conversion source such as E-beams, I-beams, oxygen plasma, or an appropriate chemical. The exposure causes the dielectric constant of the dielectric layer in the second area to increase. A number of capacitor trenches are etched in the second area of the dielectric. The capacitor trenches are then filled with an appropriate metal, such as copper, and a chemical mechanical polish is performed. The second area in which the capacitor trenches have been etched and filled has a higher capacitance density relative to the first area. In another embodiment, the exposure to the dielectric conversion source is not performed until after the chemical mechanical polish has been performed.

Abstract: Method for selective fabrication of high capacitance density areas in a low dielectric constant material and related structure are disclosed. In one embodiment, a first area of a dielectric layer is covered while a second area of the dielectric layer is exposed to a dielectric conversion source. The exposure causes the dielectric constant of the dielectric layer in the second area to increase. A number of interconnect trenches are etched in the first area of the dielectric and a number of capacitor trenches are etched in the second area of the dielectric. The interconnect trenches and the capacitor trenches are then filled with an appropriate metal, such as copper, and a chemical mechanical polish is performed. The second area in which the capacitor trenches have been etched and filled has a higher capacitance density relative to the first area.

Abstract: A varactor designed to enable voltage controlled oscillator (VCO) integration in wireless systems is the base-emitter junction of a specially optimized NPN device formed with a double base implant. A first, shallow implant optimizes capacitance, leakage current, and tuning range. A second, deeper base implant is used to improve the quality factor of the device by reducing the base resistance. The varactor includes a third terminal (collector), which isolates the emitter-base junction from the substrate, providing flexibility in circuit applications. A method for fabricating a high performance varactor having the above-described structure is also provided.

Abstract: Structure and method for fabrication of an improved capacitor are disclosed. In one embodiment, the disclosed capacitor includes a metal column comprising a number of interconnect metal segments and a number of via metal segments stacked on one another. The metal column constitutes one electrode of the capacitor. Another electrode of the capacitor is a metal wall surrounding the metal column. In one embodiment, the metal wall is fabricated from a number of interconnect metal structures and a number of via metal structures stacked on one another. In one embodiment, the metal wall is shaped as a hexagon. In this embodiment, a tight packing arrangement is achieved by packing individual hexagonal capacitors “wall to wall” so as to achieve a cluster of individual hexagonal capacitors. The cluster of individual capacitors acts as a single composite capacitor. In one embodiment, the interconnect metal and via metal are both made of copper.