Method for forming poly spacer electron tunnel oxide flash with electric-field enhancing corners for poly to poly erase

摘要

The present invention provides a method for forming a poly spacer ETOX (Electron Tunnel Oxide) flash memory device with a floating gate having electric-field enhancing corners for poly to poly erase. Here, a polysilicon spacer is used as an erase gate. A floating gate having four acute angles from top view is formed, it can raise the electric field between the floating and the erase gate. The present invention can not only raise the efficiency of the erasing mechanism but also reduce the stress produced by transferred electrodes through the tunnel oxide layer in program/erase cycles and lessen the cell size with poly to poly erase.