Nichtflüchtiges Speicherbauelement und Verfahren zu seiner Herstellung

A non-volatile memory device has gate insulating films formed on a semiconductor substrate. A tunnel insulating film is interposed between the adjacent gate insulating films. A memory transistor gate is formed on tunnel and gate insulating films. A select transistor gate is formed on gate insulating film spaced from memory transistor gate. Three doped regions are formed on the substrate. A non-volatile memory device, e.g. electrically-erasable programmable read only memory (EEPROM) cell, consists of gate insulating films, tunnel insulating film (412), memory transistor gate (450), select transistor gate (460), and three doped regions. The gate insulating films are formed on a semiconductor substrate and spaced apart from each other. The tunnel insulating film is interposed between the adjacent gate insulating films. The memory transistor gate is formed on the tunnel and gate insulating films interposing the tunnel insulating film between them. The select transistor gate is formed on the gate insulating film spaced apart from the memory transistor gate. The first doped region is formed in substrate portion under the memory transistor gate and overlaps one end of the select transistor gate. The second doped region is formed in substrate portion spaced apart from the first doped region and overlaps one end of memory transistor opposite to the select transistor gate. The third doped region is formed in substrate portion spaced apart from the first doped region and overlaps the other end of the select transistor gate. The second doped region is shallower in depth than the first and third doped regions, and includes low-density and high-density doped regions. An independent claim is included for fabrication of non-volatile memory device.