Semiconductor device having nonvolatile memory and method of manufacturing thereof

A method of manufacturing a semiconductor device, comprising the steps of:

• forming a first silicon film overlying a substrate;
• forming a silicon oxide film adjacent the first silicon film;
• annealing the silicon oxide film in a nitrogen-containing environment, at a temperature of at most 900° C., so as to incorporate nitrogen in the silicon oxide film during the annealing;
• and
• forming a second silicon film adjacent the silicon oxide film, after the annealing.

A method of manufacturing a nonvolatile memory device having an electrode in a floating state, an insulating film and a further electrode, comprising the steps of:

• forming the electrode in the floating state, overlying the substrate;
• forming the insulating film adjacent said electrode in the floating state, the insulating film being a silicon oxide film formed by chemical vapor deposition;
• annealing said silicon oxide film in a nitrogen-containing atmosphere to incorporate nitrogen in said silicon oxide film;
• and
• forming said further electrode adjacent said silicon oxide film, after said annealing.