| 摘要 |
PROBLEM TO BE SOLVED: To form a floating gate satisfying both characteristics of a tunneling insulating film interface and floating gate/control gate insulating film characteristics and to improve element characteristics and reliability. SOLUTION: A floating gate is formed on a semiconductor substrate through a tunneling insulating film. A control gate is formed on the floating gate through a gate insulating film, and an electrically rewritable memory cell is constituted. In the EEPROM, wherein a plurality of the memory cells are integrated, the floating gate is formed of double-layered polycrystalline silicon films 40a and 40b. Arsenic is doped into the silicon film 40a at the lower layer as impurities, and phosphorus is doped into the silicon film 40b at the upper layer as the impurities. COPYRIGHT: (C)2003,JPO
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