Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – Having insulated gate
Reexamination Certificate
1998-03-26
2001-01-23
Wilczewski, Mary (Department: 2822)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
Having insulated gate
C438S769000, C438S720000, C438S974000
Reexamination Certificate
active
06177312
ABSTRACT:
TECHNICAL FIELD
This invention relates to an improvement in the fabrication of non-volatile memory devices and, more particularly, to a method for removing contaminate nitrogen from the peripheral gate regions of such memory devices.
BACKGROUND OF THE INVENTION
Oxynitridation is an attractive way for scaling down tunnel oxide during the production of non-volatile memory devices. However, during the oxynitridation process, contaminate nitrogen incorporates into the peripheral transistor gate oxide layer and forms an Si—N bond with the surface of the silicon substrate in contact with the gate oxide layer. This contaminate nitrogen can not be effectively removed using conventional hydrofluoric acid dip or reoxidation techniques. The presence of such contaminate nitrogen contributes to a nonuniform gate oxide growth during subsequent gate oxidation processing. This degrades the peripheral transistor characteristics and makes oxynitridation less attractive for producing non-volatile memory devices. The present invention provides an effective way for removing this contaminate nitrogen and thus provides a solution for growing high quality gate oxide as well as taking advantage of the use of oxynitridation for tunnel oxide.
SUMMARY OF THE INVENTION
This invention relates to a method for removing contaminate nitrogen from the peripheral gate region of a non-volatile memory device during production of said device, wherein at least some of the contaminate nitrogen has formed a bond with the surface of the silicon substrate in contact with the gate oxide layer in said gate region, said method comprising: contacting said gate oxide layer and contaminate nitrogen with a gas comprising ozone at a temperature of about 850° C. to about 950° C. for an effective period of time to break said bond; and removing said gate oxide layer and contaminate nitrogen from said surface of said silicon substrate.
In one embodiment, the present invention relates to a method for treating the surface of a silicon substrate, comprising:
(A) forming spaced field oxide regions on said surface of said silicon substrate, the spaces between said field oxide regions comprising a core area and a peripheral area;
(B) forming on said surface of said silicon substrate a tunnel oxide layer in said core area and a gate oxide layer in said peripheral area, contaminate nitrogen forming in said gate oxide layer, at least some of said contaminate nitrogen forming a bond with the silicon substrate in contact with said gate oxide layer;
(C) forming a floating gate in said core area over said tunnel oxide layer;
(D) depositing a multilayered dielectric film on the surface of said field oxide regions, floating gate and gate oxide layer;
(E) forming a photoresist layer over the portion of said multilayered film overlying said floating gate;
(F) etching said multilayered film formed during step (D) in the areas not protected by the photoresist layer formed during step (E);
(G) contacting said gate oxide layer and contaminate nitrogen with a gas comprising ozone at a temperature of about 850° C. to about 950° C. for an effective period of time to break the bond formed between said contaminate nitrogen and silicon substrate; and
(H) removing said gate oxide layer and contaminate nitrogen from said surface of said silicon substrate.
REFERENCES:
patent: 5468687 (1995-11-01), Carl et al.
patent: 5489540 (1996-02-01), Liu et al.
patent: 5672521 (1997-09-01), Barsan et al.
patent: 5679585 (1997-10-01), Gardner et al.
patent: 5861347 (1999-01-01), Maiti et al.
patent: 5926741 (1999-07-01), Matsuoka et al.
patent: 5972804 (1999-10-01), Tobin et al.
E. C. Carr et al., Appl. Phys. Lett 66 (12), Mar. 20, 1995, “N Depth Profiles in Thin SiO2Grown of Processed in N2O: The Role of Atomic Oxygen”.
Chang Kent Kuohua
He Yue-song
Ibok Effiong
Ishigaki Toru
Wang John Jianshi
Advanced Micro Devices , Inc.
Park James
Renner Otto Boisselle & Sklar
Wilczewski Mary
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