| 摘要 |
PURPOSE:To form a semiconductor memory device into one which is superior in the points of reliability, integration degree and cost and also, has an easily designable circuit by applying the light to generate at the time of avalanche breakdown for erasing the contents of an EPROM. CONSTITUTION:N<+> source and drain regions 23 and 24 are provided in the island region surrounded with a field oxide film 22 on a P<-> Si substrate 21 and an N<+> semiconductor region 25 which releases electrons in a floating gate outside of the gate is provided in the vicinity of the drain region 24. The floating gate 27 is provided on the channel of the source and drain regions 23 and 24 through a first oxide film 26 and a control gate 29 is provided on this through a second oxide film 28. Moreover, a third oxide film 30 is provided on the N<+> region 25 and an interlayer insulating film 31 is provided on the field oxide film 22, the control gate 29 and so on. A source electrode 33, a drain electrode 34 and an electrode 35 for erase are each provided in contact holes 32... provided in the first oxide film 26 or the third oxide film 30 and the interlayer insulating film 31.
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