| 摘要 |
PURPOSE: A method for manufacturing a flash memory cell is provided to restrain the formation of grain boundary and a native oxide by using a floating gate including a doped polysilicon layer and an undoped polysilicon layer. CONSTITUTION: A tunnel oxide layer, the first silicon layer(104) made of undoped polysilicon and a pad nitride layer are stacked on an isolation region of a substrate(101). After a trench is formed, an isolation layer is formed in the trench. After the pad nitride layer is removed, the second silicon layer(110) made of doped polysilicon and the third silicon layer(111) made of undoped polysilicon are sequentially formed on the resultant structure and selectively patterned, thereby forming a floating gate(117). After a dielectric film(113) is formed on the resultant structure, a control gate(116) including the fourth silicon layer(104) and a silicide layer(115) is formed.
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