Semiconductor device and a method of producing the same

A semiconductor device having a memory device region and a logic device region on a principle surface of a semiconductor substrate comprising:

• a pair of first and second source/drain areas formed with an interval so as to sandwich a first channel region on a principle surface of said memory device region;
• a pair of first and second low concentration impurity regions formed with an interval so as to sandwich a second channel region on a principle surface of said logic device region;
• a first gate electrode and a second gate electrode formed on a gate oxide film respectively formed on said first channel region and said second channel region;
• silicon oxide film formed so as to cover said first gate electrode and said second gate electrode;
• a silicon nitride film formed on said silicon oxide film;
• an inter-layer insulating film formed on said silicon nitride film;
• a self-alignment contact opening formed in an area above said first source/drain area of said inter-layer insulating film, said silicon nitride film, and said silicon oxide film formed on said memory device area;
• a side wall film made of said silicon oxide film and said silicon nitride film extending through areas above said first and second low concentration impurity regions so as to cover an upper portion and a side wall of said second gate electrode formed on said logic device area;
• first and second high concentration impurity regions formed from end portions of said side wall film on said semiconductor substrate formed on said logic device area;
• and
• a high-melting metallic silicide film formed on said semiconductor substrate surfaces of said first and second high concentration impurity regions, wherein
• said silicon oxide film and said silicon nitride film formed on said upper portion and said side surface of the second gate electrode in said logic device region have a function as a silicon protection film in addition to a function as the side wall film for said second gate electrode.