| 摘要 |
PURPOSE:To enable a floating-gate-type EEPROM to perform a larger number of writing or deleting operations, by utilizing a CVD insulation film as a tunnel oxide film for exchanging charges with a floating gate electrode. CONSTITUTION:A P-type semiconductor substrate 1 has an N<+> type source region 2 and a drain region on the surface thereof, and a gate oxide film 4 is provided over there. A 100Angstrom thick CVD insulation film 5 is formed on a small region near the drain, and a floating gate electrode 6, a second gate oxide film 7 and a control gate electrode 8 are provided thereon. The CVD insulation film 5 is produced from dichlorosilane (SiH2Cl2) and nitrous oxide (N2O) under a reduced pressure at a temperature of 700-900 deg.C. The CVD insulation film 5 is hardly broken down dielectrically since it has a higher breakdown current density than a thermal oxide film 15 in its region having as a small thickness as 100Angstrom . Therefore, it allows to substantially increase the number of writing or deleting operations that the storage device can perform.
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