US Patent 7312484 Pixel having an oxide layer with step region

A semiconductor structure, having a doped well region being formed in a substrate layer and a transistor having a terminal provided within said doped well region. The semiconductor structure also includes an oxide layer formed over the substrate layer, the doped well region, a poly silicon region, and the terminal of the transistor. The oxide layer including a step region being located where a height of the oxide layer transitions from a height associated with the doped well region to a height associated with the terminal of the transistor.