Semiconductor device and method of manufacturing the same
View Patent ↗The present invention relates to a semiconductor device that includes a semiconductor substrate ( 10 ) having source/drain diffusion regions ( 14 ) formed therein and control gates ( 20 ) formed thereon, with grooves ( 18 ) being formed on the surface of the semiconductor substrate ( 10 ) and being located below the control gates ( 20 ) and between the source/drain diffusion regions ( 14 ). The grooves ( 18 ) are separated from the source/drain diffusion regions ( 14 ), thereby increasing the effective channel length to maintain a constant channel length for charge accumulation while enabling the manufacture of smaller memory cells. The present invention also provides a method of manufacturing the semiconductor device.
1. A method of manufacturing a semiconductor device, comprising:
forming a groove on a semiconductor substrate, the groove formed therein to extend in a first direction, wherein forming the groove comprises:
forming a silicon oxide film in a surface of the semiconductor substrate;
forming an insulating film having an opening on the semiconductor substrate with a sidewall formed around the opening;
forming source/drain diffusion regions between which the groove is located, the source/drain diffusion regions formed therein to extend in the first direction, wherein forming the source/drain diffusion regions comprises implanting ions in the semiconductor substrate, with a mask being formed with the silicon oxide film and the sidewall;
forming an ONO film on the semiconductor substrate over the groove and the source/drain regions; and
forming a control gate on the ONO film, the control gate formed therein to extend in a second direction perpendicular to the first direction, the control gate provided over portions of the groove and the source/drain regions.
2. The method as claimed in claim 1 , wherein forming the groove further comprises:
thermally oxidizing a surface of the semiconductor substrate to form the silicon oxide film; and
removing the silicon oxide film.
3. The method as claimed in claim 2 ,
wherein thermally oxidizing the surface of the semiconductor substrate utilizes the insulating film and the sidewall as a mask.
4. The method as claimed in claim 3 , wherein the insulating film is formed with silicon nitride film, and wherein the sidewall is formed with silicon oxide film.
5. The method as claimed in claim 1 , wherein the groove is formed below the control gate and between the source/drain regions.
6. The method as claimed in claim 5 , wherein the groove is separated from the source/drain regions by a predetermined distance.
7. The method as claimed in claim 1 , wherein the source/drain diffusion regions are formed self-aligned with the groove.
8. The method as claimed in claim 1 , wherein forming the groove comprises etching.
9. The method as claimed in claim 1 , wherein the groove is formed a distance equivalent to the width of each sidewall from each adjacent source/drain region.
10. A method of manufacturing a semiconductor device, comprising:
forming a groove on a semiconductor substrate, the groove formed therein to extend in a first direction;
forming source/drain diffusion regions between which the groove is located, the source/drain diffusion regions formed therein to extend in the first direction, wherein the groove is separated from the source/drain diffusion regions by a distance equivalent to a width of sidewalls formed around an opening in an insulating film formed on the semiconductor substrate, the sidewalls serving as a mask during the source/drain diffusion region formation;
forming an ONO film on the semiconductor substrate over the groove and the source/drain regions; and
forming a control gate on the ONO film, the control gate formed therein to extend in a second direction perpendicular to the first direction, the control gate provided over portions of the groove and the source/drain regions.
11. The method as claimed in claim 10 , wherein forming the groove comprises:
thermally oxidizing a surface of the semiconductor substrate to form a silicon oxide film; and
removing the silicon oxide film.
12. The method as claimed in claim 11 , wherein thermally oxidizing the surface of the semiconductor substrate utilizes the insulating film and the sidewall as a mask.
13. The method as claimed in claim 12 , wherein forming the source/drain diffusion regions comprises implanting ions in the semiconductor substrate, with a mask being formed with the silicon oxide film and the sidewall.
14. The method as claimed in claim 12 , wherein the insulating film is formed with silicon nitride film, and wherein the sidewall is formed with silicon oxide film.
15. The method as claimed in claim 10 , wherein the groove is formed below the control gate and between the source/drain regions.
16. The method as claimed in claim 15 , wherein the groove is separated from the source/drain regions by a predetermined distance.
17. The method as claimed in claim 10 , wherein the source/drain diffusion regions are formed self-aligned with the groove.
18. The method as claimed in claim 10 , wherein the step of forming the groove comprises etching.