Abstract: A new method of using a NO or N.sub.2 O treatment on a first area on a wafer in order to form a thinner oxide film in the first area and a thicker oxide film in a second area on a wafer using a single oxidation step is achieved. A semiconductor substrate of a silicon wafer is provided wherein a first area is separated from a second area by an isolation region. The silicon substrate in the second area is treated with NO or N.sub.2 O whereby a high-nitrogen silicon oxide layer is formed on the surface of semiconductor substrate in the second area. A tunnel window is defined in the first area and the oxide layer within the tunnel window is removed. The silicon wafer is oxidized whereby a tunnel oxide layer forms within the tunnel window and whereby a gate oxide layer is formed overlying the high-nitrogen silicon oxide layer in the second area. The tunnel oxide layer has a greater thickness than the combined thickness of the gate oxide layer and the high-nitrogen silicon oxide layer.

Abstract: A method of forming dielectric films is described wherein the low dielectric constant of a layer of dielectric material having a low dielectric constant, such as low dielectric constant spin-on-glass, is stabilized to prevent subsequent processing steps from increasing the dielectric constant. The layer of dielectric material having a low dielectric constant is treated in an inert atmosphere, such as nitrogen or argon, at an elevated temperature. This inert atmosphere treatment of the dielectric prevents the dielectric constant from increasing during subsequent processing steps.