SEMICONDUCTOR DEVICE AND ITS FABRICATING METHOD

摘要

PROBLEM TO BE SOLVED: To obtain a semiconductor device in which electrical insulation is ensured sufficiently between a bit line and a word line and excellent charge holding characteristics are realized by suppressing troubles, e.g. generation of a bird's beak. SOLUTION: In a buried bit line type flash memory arranged such that a bit line 5 functioning as source-drain formed by implanting impurity ions into a semiconductor substrate 1 intersects a word line 7 functioning as a gate electrode, a three layer structure ONO film 6 of silicon oxide film/silicon nitride film/silicon oxide film is formed after impurity ions for forming the bit line 5 are implanted and annealing for activation is performed.