According to the present invention, there is provided a non-volatile semiconductor memory device including a memory cell array in which a plurality of memory cells are arranged, wherein the memory cells contain two or more types of memory cells, which differs in gate couple ratio. Each memory cell includes...http://www.google.de/patents/US5953610?utm_source=gb-gplus-sharePatent US5953610 - Method of fabricating non volatile memory device with memory cells which differ in gate couple ratio
