| 摘要 |
PURPOSE:To obtain an EEPROM in which erroneous writing of information is prevented and the reading speed of the information is improved even if a channel length becomes short accompanied by the implementation of high integration density, by providing a tunnel insulating film, in which a tunnel current flows, between a control gate and a floating gate. CONSTITUTION:First and second diffused regions 23 and 24, which are to become source and drain regions are provided, in the surface region of a semiconductor substrate 13. An insulating film 15 is formed on a channel region between the diffused regions 23 and 24. A control gate 16a and a floating gate 19a, which is adjacent to the control gate 16a, are provided on a region of a part of the film 15. A tunnel insulating film 18, in which a tunnel current flows, is formed between the floating gate 19a and the control gate 16a. For example, a high voltage of about 20 V is applied across the control gate 16a and the N<+> type diffused region 23. Then the tunnel current flows between the control gate 16a and the floating gate 19a through the thin oxide film 18. Thus electric charge is injected in the floating gate 19a. |
