Method for fabricating a silicon-oxide-nitride-oxide-silicon (SONOS) non-volatile memory cell

摘要

The invention provides a method for fabricating a silicon-oxide-nitride-oxide-silicon (SONOS) non-volatile memory cell, comprising: (S1) forming a pad oxide pattern on a silicon substrate having a recess exposing a tunnel region of the silicon substrate; (S2) forming a bottom oxide layer, a nitride layer, a top oxide layer covering the recess and the pad oxide pattern to form a first ONO structure; (S3) forming a photoresist on the first ONO structure covering the recess and a peripheral region of the pad oxide pattern; (S4) removing a part of the first ONO structure exposed by the photoresist to form an U-shaped ONO structure; (S5) trimming the photoresist to exposed a part of the U-shaped ONO structure above the recess; (S6) removing the part of the U-shaped ONO structure; (S7) removing the photoresist; (S8) removing the pad oxide pattern and the top oxide layer; and (S9) forming a gate structure.

主权项

1. A method for fabricating a silicon-oxide-nitride-oxide-silicon (SONOS) non-volatile memory cell, comprising steps of:
(S1) forming a pad oxide pattern on a silicon substrate having a recess exposing a tunnel region of the silicon substrate; (S2) forming a bottom oxide layer, a nitride layer, a top oxide layer in sequence conformally covering the recess and the pad oxide pattern to form a first ONO structure; (S3) forming a photoresist on the first ONO structure covering the recess and a peripheral region of the pad oxide pattern; (S4) removing a part of the first ONO structure exposed by the photoresist to form an U-shaped ONO structure; (S5) trimming the photoresist to exposed a part of the U-shaped ONO structure above the recess; (S6) removing the part of the U-shaped ONO structure above the recess; (S7) removing the photoresist; (S8) removing the pad oxide pattern and the top oxide layer; and (S9) forming a gate structure in the tunnel region.