Patent ID: 8659080

Claim:
A semiconductor structure, comprising: a substrate having a first conductive type; a well having a second conductive type formed in the substrate; a first doped region and a second doped region formed in the well; a field oxide formed on a surface region of the well and between the first doped region and the second doped region; a first dielectric layer formed on the surface region and covering an edge portion of the field oxide, the first dielectric layer has a first thickness; a second dielectric layer formed on the surface region, the second dielectric layer has a second thickness smaller than the first thickness: and a gate conductive layer formed on a portion of the first dielectric layer which covers the field oxide, such that a position of the gate conductive layer is located on the field oxide covered by the portion of the first dielectric layer, wherein the size of an area of the field oxide covered by the portion of the first dielectric layer is greater than the size of an area of the field oxide covered by the gate conductive layer.