| 摘要 |
PURPOSE:To increase the area of overlapping by each laminating two layers of polycrystalline silicon layers onto a polycrystalline silicon layer as a floating gate through insulating films and arranging the floating gate so that several polycrystalline silicon layer as upper-most layers is mutually connected electrically. CONSTITUTION:A field insulating film 10 is formed to the surface of a substrate 1, and an insulating film 5 in a region 12, a region 13 and an insulating film 3 are shaped. Arsenic ions are implanted through the insulating film 3 to form a diffusion layer 2. A polycrystalline silicon layer as a floating gate 4 is shaped and the insulating film 5 is formed, a polycrystalline silicon layer as a control gate 6 is shaped, and an insulating film 7 is formed through oxidation. A gate 8 consisting of a polycrystalline silicon layer is shaped, conducted electrically with the floating gate 4 by a contact 9 through patterning, and unified as a floating gate. Source-drain regions and an inter-layer insulating film are formed, and a contact hole is bored and metallic wirings, etc. are shaped. Accordingly, a capacity ratio is removed, thus allowing writing and erasing at high speed. |
