摘要 |
A cumulative capacitor structure with desirably constant capacitance characteristics is disclosed. In one embodiment, the cumulative capacitor includes a set of four capacitors coupled in parallel between first and second terminals of the cumulative capacitor. In one embodiment, the first capacitor is comprised of a top plate formed of an n-type polysilicon coupled to the first terminal, a bottom plate comprised of a first accumulation/depletion region such as an n-well region coupled to the second terminal, and a first dielectric region between its top and bottom plates. The second capacitor has an n-type polysilicon terminal top plate coupled to the second terminal, an accumulation/depletion region bottom plate coupled to the first terminal, and a dielectric between its top and bottom plate. A third capacitor has a p-type polysilicon top plate coupled to the first terminal, an accumulation/depletion region bottom plate coupled to the second terminal, and a third dielectric region between its top and bottom plates. The fourth capacitor has a p-type polysilicon terminal coupled to the second terminal, an accumulation/depletion region bottom plate coupled to the first terminal, and a dielectric between its top and bottom plates.
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