A circuit for a pixel site in an imaging array includes a light-detecting element to convert incident light to a photocurrent and a reset transistor, operatively connected to the light-detecting element, to reset a voltage associated with the light-detecting element. The method further includes performing a polysilicon CMP process on the polysilicon layer, where the polysilicon CMP process removes a substantial percentage of the polysilicon nodule defects from the top surface of the polysilicon layer. Then, a second low dielectric constant film having a specific dielectric constant of k less than 3 is formed over the first protection layer so that an edge of the second low dielectric constant film is located at the first position.