Method of manufacture of undoped polysilicon as the floating-gate of a split-gate flash cell

摘要

Form a split gate EEPROM memory device on a doped silicon semiconductor substrate starting with an initial oxide layer and form an undoped first polysilicon layer thereon. Then form a polysilicon oxide hard mask over the undoped first polysilicon layer for use in patterning the initial oxide layer and the undoped first polysilicon layer which are then etched to form a floating gate electrode stack from the undoped first polysilicon layer and the initial oxide layer on the substrate. Then form a tunnel oxide layer and a doped polysilicon and pattern them into control gate electrode stack, with the control gate electrode stack being located in a split-gate configuration with respect to the floating gate electrode stack.