Non-volatile flash memory cell

Abstract

A method for manufacturing a flash memory device on a substrate may include: preparing the substrate with shallow trench isolation to define active sections; depositing a floating gate oxide layer on the prepared substrate; depositing a floating gate polysilicon layer on the floating gate oxide layer; polishing the floating gate polysilicon layer to isolate a plurality of floating gates above the active sections of the substrate; depositing a silicon nitride layer on top of the plurality of floating gates; patterning and etching the silicon nitride layer to create silicon nitride features; depositing a set of oxide spacers along sides of the silicon nitride features; implanting a source junction into the substrate beneath the individual floating gates; removing the floating gate polysilicon layer except where beneath individual oxide spacers, then removing the set of oxide spacers; depositing an inter-poly layer on top of the remaining floating gates; depositing a second polysilicon layer on top of the inter-poly layer; and patterning and etching the second polysilicon layer to separate the second polysilicon layer into word line devices and erase gates.