Non-volatile semiconductor memory device having multiple different sized floating gates

摘要

The object of the present invention is to provide a non-volatile semiconductor memory device which is capable of increasing a integration density of a memory cell by increasing the number of states to be expressed with one memory cell.A non-volatile semiconductor memory device of the present invention has a structure in which two floating gates (3, 4) under one control gate (5) having a minimum dimension are provided, each of two floating gates is able to express two values in accordance with existences of stored charges whereby one memory cell is able to express four values and the widths of the two floating gates are different.