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A method is provided, the method comprising forming a first dielectric layer above a structure layer, the first dielectric layer having an upper portion. The method also comprises grading the upper portion of the first dielectric layer using at least one of monomethyl silane, dimethyl silane, trimethyl silane, and tetramethyl silane with helium (He) and at least one of nitrous oxide (N 2 O) and molecular nitrogen (O 2).