| 摘要 |
PURPOSE:To improve an erasure characteristic and to reduce an effect due to the nonuniformity in a film thickness, by using a CVD method when an insulating layer is formed on an erase gate, and by forming this insulating layer so that it has a large film thickness. CONSTITUTION:A field oxide film 12 is formed on the surface of a substrate, and further a polycrystalline Si layer is formed by deposition. Next, the polycrystalline Si layer is doped with an impurity and thereafter removed selectively so as to form an erase gate 18. Then, an insulating layer 13 is formed, and thereafter only an oxide film on the gate 18 is removed selectively. Next, an insulating layer 20 is formed on the gate 18 by using a CVD method. There after a polycrystalline Si layer is formed by deposition on the whole surface of the base by using the CVD method. Then, a floating gate 16 is formed in this polycrystalline Si layer. Thereafter, an insulating layer 14 is formed, Then, a polycrystalline Si layer is deposited on the base, and an impurity is doped to form a control gate 17. |
