NONVOLATILE SEMICONDUCTOR MEMORY DEVICE AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device that allows writing by using channel hot electrons and an erasure by FN tunnel phenomenon over the entire channel surface. SOLUTION: A memory cell gate 2 is formed on a main surface of a semiconductor substrate 1 via a gate insulating film 5. On either side of the memory cell gate 2, a source region 3 and a drain region 4 are formed. The source region 3 has a p- impurity region 3a and an n+ impurity region 3b, and the drain region 4 has a p- impurity region 4a and an n+ impurity region 4b. The concentration of the p- impurity region 3a is higher than that of the p- impurity region 4a, and the concentration of the n+ impurity region 3b is higher than that of the n+ impurity region 4b.