| 摘要 |
PROBLEM TO BE SOLVED: To improve characteristics and reliability of a memory cell by stabilizing operation quality in data writing in the split gate type EEPROM memory cell. SOLUTION: A low concentration source region 7a is formed by implanting phosphorus ion into a p-type semiconductor substrate 1 taking a spacer film 5 as a mask. Then, the side surface of a polysilicon film 3 is coated with a side cap film 6. Then, a high concentration source region 7b is formed by implanting arsenic ion taking the side cap film 6 as a mask. It is possible to keep the width of the low concentration source region 7a wide also after thermal diffusion in order to secure the low concentration source region 7a before the thermal diffusion corresponding to the width of the side cap film 6. It is therefore possible to secure withstand voltage in the low concentration source region 7a and prevent a short channel effect. COPYRIGHT: (C)2006,JPO&NCIPI
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