| 摘要 |
PURPOSE:To reduce the irregularity of the whole capacity by forming large unevenness on a floating gate electrode to increase the value of a capacity between electrodes. CONSTITUTION:A first floating gate electrode region is patterned by a photolithography technique and an etching technique. Then, when the photolithography and dry etching techniques are again used to remove by etching the region of a recess 5 so that a remaining polycrystalline silicon film containing an impurity becomes 1000-7000Angstrom , floating gate electrode recesses 5 and protrusions 6 are formed. Then, a control gate electrode 8 is formed through an interlayer insulting film on the recesses 5 and the protrusions 6, and a control gate electrode 8 is made uneven in coincidence with the uneveness of the gate electrode. Thus, since a capacity between the gate electrodes can be increased, the irregularity of an electric field to a tunnel oxide film 4 can be reduced.
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