Patent ID: 6835977
Filing Date: 2004-12-28
Classification: H01L

Abstract:
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 including a contact 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 the second conductivity type ion-doped region and the conductive layer are located within the same active device region of the substrate, and the conductive layer is isolated from the second conductivity type ion-doped region through an insulation layer.