| 摘要 |
PURPOSE:To make an extremely fine opening with good controllability by a method wherein, after the opening reaching the surface of a drain layer has been made by a lithographic technique, a third insulating film is left on the side of this opening by an anisotropic etching method. CONSTITUTION:A thick SiO2 film 12 is formed on a P-type Si substrate 11; then, an N-type source and an N-type drain 13, 14 are formed. Then, a thin SiO2 film 15 and a thin SiN film 16 for floating gate use are applied and formed. After that, an opening 18 is made. Then, an SiO2 film 19 is applied. Then, the SiN film 16 is removed partially in such a way that it is left only on the drain region. After that, the exposed Si substrate is thermally oxidized via the opening; a thin SiO2 film 20 is formed. Then, after a poly-Si film 22 has been applied, it is removed partially and a floating gate electrode is formed. Then, an SiO2 film 23 is applied; an insulating film for control gate use is formed; furthermore, a control gate composed of the poly-Si film 23 is formed.
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