Merchant & Gould P.C.
Method for forming the self-aligned buried N+ type to diffusion process in ETOX flash cell
A method for forming the self-aligned buried N+-type to diffusion process in ETOX flash cell is disclosed. The method at least includes the following steps. First of all, a substrate is provided having a pad oxide layer thereon, a dielectric layer on the pad oxide layer, and a cap layer on the dielectric layer. Then, a portion of the cap layer and the dielectric layer are etched to stop on the pad oxide layer to define an active region. Then, a spacer is formed on sidewall of the dielectric layer. Next, a portion of the pad oxide layer and the substrate are etched through said buried N+-type region to form an opening in the substrate. Finally, a field oxide region is formed in the substrate.
United Microelectronics Corp.
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inventional inventional inventional
Cheng-Jyi
Chang