PURPOSE: To obtain a tunnel thin-film, defects therein are extremely few and which has excellent film quality, by using an oxide film acquired by oxidizing an epitaxial growth layer immediately after the formation of the epitaxial growth layer as the tunnel thin-film.

CONSTITUTION: An inter-element insulating isolation region 12 is formed to the surface of a P type silicon substrate 11, and an element forming region 13 is demarcated. An oxide film 14 as a gate insulating film is formed to the surface of the region 13. A rewriting region 15 is demarcated to one part of the oxide film 14. An Si crystal layer 16 is shaped to the surface of the substrate 11. The surface of the Si crystal layer 16 is oxidized to form an SiO2 film 17. A first polycrystalline Si layer 18 as a floating gate is formed on the SiO2 film 17 as a tunnel thin-film. An SiO2 film 19 is formed to the surface of the Si layer 18. A second polycrystalline Si layer 20 is shaped on the Si substrate 11 containing the upper section of the SiO2 film 19, and used as a control gate. The surfaces of the Si substrate 11 are exposed to form a drain region and a source region.