Patent ID: 7157766
Filing Date: 2007-01-02
Classification: H01L

Abstract:
1. A variable capacitor structure, comprising: a substrate; a first conductivity type ion-doped well within the substrate, wherein the first conductivity type ion-doped well has a cavity; a first conductivity type ion-doped buried layer in the substrate underneath the first conductivity type ion-doped well, wherein the first conductivity type ion-doped buried layer and the first conductivity type ion-doped well are connected; a second conductivity type ion-doped region at the bottom of the cavity of the first conductivity type ion-doped well; and a conductive layer over the first conductivity type ion-doped buried layer, wherein the conductive layer and the first conductivity type ion-doped buried layer are connected, wherein a distance from a top surface of the second conductivity type ion-doped region to a top surface of the first conductivity type ion-doped buried layer is smaller than a thickness of the conductive layer.