| 摘要 |
PURPOSE:To extend the freedom in circuit design of EPROM device by means of providing floating gates at both sidewall parts opposing to a control gate. CONSTITUTION:A control gate 5 is formed on a substrate 1 in an element region encircled by a field oxide film 2 through the intermediary of a gate insulating film comprising a double layer structure of an oxide film 3 and a nitride film 4 while the sidewall parts and upper surface of this control gate 5 are covered with another oxide film 6 and another nitride film 7. Furthermore, floating gates 8' comprising polycrystalline silicon are formed on the sidewall parts of control gate 5. Besides, source drain regions in LDD structure comprising shallow N<->regions 9 as well as deep n<+>regions 10 are formed outside the floating gate 8' in the substrate. Through these procedures, the source and drain regions are not decided in principle but to be selected freely subject to the design requirements.
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