Sidewall SONOS Gate Structure with Dual-Thickness Oxide and Method of Fabricating the Same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsTzyh-Cheang Lee, Jiunn-Ren Hwang, Tsung-Lin Lee
Life of this patent
Estimating the term…
Abstract
A SONOS gate structure has an oxide structure on a substrate having gate pattern thereon. The oxide structure has a relatively thinner oxide portion on the substrate for keeping good program/erase efficiency, and a relatively thicker oxide portion on sidewalls of the gate pattern for inhibiting gate disturb. Trapping dielectric spacers are on formed the oxide structure laterally adjacent to said sidewalls of said gate pattern respectively.
Claims15
A method of forming a SONOS gate structure, comprising:
- forming a gate pattern with sidewalls on a substrate, wherein said gate pattern comprises a gate dielectric layer patterned on said substrate and a gate electrode patterned on said gate dielectric layer;
- forming a first oxide layer on said gate pattern and said substrate;
- etching back said first oxide layer to expose said substrate and the top of said gate electrode, leaving oxide spacers along said sidewalls of said gate pattern respectively;
- forming a second oxide layer on said substrate and said oxide spacers, wherein said second oxide layer on said substrate is a relatively thinner oxide portion, and a combination of said oxide spacer and said second oxide layer along one of said sidewalls of said gate pattern is a relatively thicker oxide portion;
- and
- forming trapping dielectric spacers on said second oxide layer adjacent to said sidewalls of said gate pattern respectively.
A method of forming a SONOS gate structure, comprising:
- forming a gate pattern with sidewalls on a substrate, wherein said gate pattern comprises a gate dielectric layer patterned on said substrate and a gate electrode patterned on said gate dielectric layer;
- forming a first oxide layer on said gate pattern and said substrate;
- forming a first dielectric layer on said first oxide layer;
- etching back said first dielectric layer to expose said first oxide layer, leaving first dielectric spacers on said first oxide layer adjacent to said sidewalls of said gate pattern respectively;
- etching back said first oxide layer and said first dielectric spacers to expose said substrate and the top of said gate electrode, leaving oxide spacers along said sidewalls of said gate pattern respectively, and leaving said first dielectric spacers on said oxide spacers respectively;
- forming a second oxide layer on the exposed portions of said substrate, said gate electrode and said oxide spacers;
- forming a second dielectric layer on said first dielectric spacers and said second oxide layer;
- and
- etching back said second dielectric layer to expose said second oxide layer, leaving second dielectric spacers adjacent to said sidewalls of said gate pattern respectively.
The method of forming a SONOS gate structure of claim 13, wherein said first dielectric layer and said second dielectric layer are formed of silicon nitride.
Dependencies are inferred from the claim text.