Method of fabrication a non-volatile semiconductor memory device with shielded single polysilicon gate memory part

摘要

Process for manufacturing a semiconductor memory device comprising the formation, in a same semiconductor material chip, of at least a first memory cell (18) comprising a MOS transistor (19) with a first gate electrode (21) and a second gate electrode (23) superimposed and respectively formed by definition in a first (12) and a second layer (17) of conductive material, and of at least a second memory cell (1) shielded by a layer (32) of shielding material for preventing the information stored in the second memory cell (1) from being accessible from the outside, said second memory cell (1) comprising a MOS transistor (2) with a floating gate electrode (4) formed simultaneously with the first gate electrode (21) of the first cell (18) by definition of said first layer of conductive material (12). Said layer of shielding material (32) is formed by definition of said second layer of conductive material (17).