A stainless steel foil contains, in percent by mass, 0. An organic carboxylate composition, obtained by heating and mixing a basic silane coupling agent and an amine compound with a softening point or melting point of 40\xb0 C. The source system receives corresponding identification data. In writing the data into the memory cell, a first write operation is to apply a write pulse voltage with a first step-up voltage between the gate electrode and the semiconductor substrate.