| 摘要 |
PURPOSE:To overlap both gates without an extra space for isolating both gates, by providing a two-layer structure of a selecting gate and a floating gate. CONSTITUTION:An element isolating region 10 is formed on a substrate 11. Then, after a gate oxide film is formed, a word line 3 is formed with a first polycrystalline Si layer, and an interlayer insulating film is formed. Then, a tunnel oxide film 6 is formed. Thereafter, impurities are implanted in a gate region, and regions 8, 9 and 12 are formed. Then, a floating gate 2 is formed with a second polycrystalline Si layer, and an interlayer insulating film is formed. Then, a control gate 1 is formed with a third polycrystalline Si layer, and an interlayer insulating film is formed. Finally, a bit line 4 is formed. |
