| 摘要 |
PURPOSE:To reduce an area occupied by a storage element and to enable the reduction of a program voltage Vpp, by making small the thickness of a part of the region of an interlayer insulation film formed between a floating gate and a control gate, and by using the part as a tunnel region. CONSTITUTION:A tunnel region 26 included in an interlayer insulation film 31 is formed by a method wherein: after the interlayer insulation film 31 is formed on a floating gate 22, the interlayer insulation film in a desired position on the floating gate 22 is etched to expose a part of the top surface of the floating gate 22, and thereafter an oxide film is made to grow on the surface of polysilicon constituting the floating gate 22 by using a thermal oxidation method. Accordingly, the thickness of the interlayer insulation film 31 is smaller in the part of the tunnel region 26 than in the other part. Since the area of a region 33 wherein the floating gate 22 and a drain region overlap each other, for instance, can be made large appropriately by this method, it becomes possible to set a value of a program Vpp to be small. |
