摘要 |
A flash memory device manufacturing process includes the steps of providing a semiconductor substrate; forming two gate structures on the substrate; performing an ion implantation process to form two first source regions in the substrate at two lateral outer sides of the two gate structures; performing a further ion implantation process to form a first drain region in the substrate between the two gate structures; performing a pocket implantation process between the gate structures to form two doped regions in the substrate at two opposite sides of the first drain region; forming two facing L-shaped spacer walls between the two gate structures above the first drain region; performing an ion implantation process to form a second drain region beneath the first drain region, both of which having a steep junction profile compared to the first source regions; and forming a barrier plug above the first drain region.
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