Semiconductor device and method of manufacturing the same

Abstract

A gate electrode is formed on a semiconductor substrate via a second gate insulating film, and a floating gate electrode is formed on the semiconductor substrate via a first gate insulating film. A second sidewall spacer is formed on a side surface of the gate electrode, and a first sidewall spacer is formed on a side surface of the floating gate electrode. A first insulating film made of silicon oxide covers the floating gate electrode, and a second insulating film made of silicon nitride covers the gate electrode, the floating gate electrode, the second sidewall spacer, the first sidewall spacer, and the first insulating film. The first insulating film is interposed between an upper surface of the floating gate electrode and the second insulating film. A density of the upper portion of the first insulating film BL is larger than that of the lower portion of the first insulating film.

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