| 摘要 |
PURPOSE:To contrive the improvement in interlayer dielectric strength between two gates by providing a phosphorus glass layer on a surface of a floating gate consisting of polysilicon and providing a control gate while using said phosphorus glass layer at least as a part of an interlayer insulating film. CONSTITUTION:A field oxide film 2 is arranged on one main plane of a P-type silicon substrate 1 and a P-type region 3 is formed by usual thermal diffusion. Then, the field oxide film 2 on a gate region is removed and a gate oxide film 4 is formed, on which a polysilicon floating gate 5 is formed. Phosphorus is diffused in order to improve conductivity of the floating gate 5. At this time, a phosphorus glass layer 6 is produced on a surface of the polysilicon layer as a floating gate. Next, thermal oxidation is done to form an oxide film 7 while leaving the phosphorus glass layer 6. On that film 7, a polysilicon control gate 8 is formed and phosphorus is diffused in order to apply conductivity to this control gate 8. At the same time, source and drain regions 9 are formed in the substrate. After oxidation, an opening is formed to provide an aluminum electrode 10.
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