| 摘要 |
PROBLEM TO BE SOLVED: To increase capacity between a floating gate electrode and a control gate electrode without lowering the reliability between them or increasing the memory size by making a trench in the floating gate electrode extending in the breadthwise direction thereof. SOLUTION: Since a trench 4a having recessed cross-section in the longitudinal direction of the gate is made on a floating gate electrode 4 in a semiconductor memory, surface area can be increased between the floating gate electrode 4 and a control gate electrode 6. Consequently, capacity between the floating gate electrode 4 and the control gate electrode 6 can be increased without making thin a second gate insulating film 5 or increasing overlap between the floating gate electrode 4 and a field oxide film 2 as required in prior art, and the reliability of gate insulating films 3, 5 can be ensured while reducing cell size.
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