Abstract: A method is provided for forming isolated regions of oxide of an integrated circuit, and an integrated circuit formed according to the same. A pad oxide layer is formed over the integrated circuit. A nitrogen doped polysilicon layer is formed over the pad oxide layer. A thick nitride layer is then formed over the nitrogen doped polysilicon layer. An opening is formed in the nitride layer and the nitrogen doped polysilicon layer exposing a portion of the pad oxide layer. The nitrogen doped polysilicon layer is annealed encapsulating the polysilicon layer in silicon nitride. A field oxide region is then formed in the opening.