Semiconductor device and method for manufacturing thereof
View Patent ↗A semiconductor device includes bit lines provided in a semiconductor substrate; an ONO film that is provided along the surface of the semiconductor substrate and is made of a tunnel oxide film, a trap layer, and a top oxide film; and an oxide film that is provided on the surface of the semiconductor substrate in the middle between the bit lines and contacts the side face of the ONO film, in which the film thickness of the oxide film is larger than the sum of the thicknesses of the tunnel oxide film and the top oxide film, and smaller than the thickness of the ONO film.
1. A method for manufacturing a semiconductor device, comprising:
forming a bit line in a semiconductor substrate;
forming along a surface of the semiconductor substrate an oxide-nitride-oxide (ONO) film that includes a tunnel oxide film, a trap layer made of a nitride film, and a top oxide film;
etching the top oxide film in a middle portion between the bit lines along the surface of the semiconductor substrate; and
oxidizing the trap layer under a portion where the top oxide film is etched.
2. The method for manufacturing a semiconductor device according to claim 1 , further comprising:
forming in an area in the semiconductor substrate between the bit lines a portion defining a groove that contacts the bit line;
wherein the ONO film is formed along an inner surface of the groove.
3. The method for manufacturing a semiconductor device according to claim 1 , wherein oxidizing the trap layer includes oxidizing the trap layer using as a mask a second sidewall layer formed on a sidewall of the top oxide film.
4. The method for manufacturing a semiconductor device according to claim 1 , wherein oxidizing the trap layer comprises oxidizing the trap layer through low temperature radical oxidation.
5. The method for manufacturing a semiconductor device according to claim 1 , wherein oxidizing the trap layer comprises entirely oxidizing the trap layer.
6. The method for manufacturing a semiconductor device according to claim 1 , wherein oxidizing the trap layer comprises oxidizing the trap layer with a portion of the trap layer remaining.
7. The method for manufacturing a semiconductor device according to claim 1 , wherein etching the top oxide film comprises etching the top oxide film so that part of the top oxide film remains.
8. The method for manufacturing a semiconductor device according to claim 7 , wherein an etching amount of the top oxide film is substantially equal to an oxidation amount of the trap layer.
9. The method for manufacturing a semiconductor device according to claim 1 , wherein etching the top oxide film comprises entirely etching the top oxide film.
10. The method for manufacturing a semiconductor device according to claim 9 , wherein a thickness of the top oxide film is substantially equal to an oxidation amount of the trap layer.
11. A method for manufacturing a semiconductor device, comprising:
forming on a surface of a semiconductor substrate an oxide-nitride-oxide (ONO) film that includes a tunnel oxide film, a trap layer made of a nitride film, and a top oxide film;
forming a mask layer on the ONO film;
forming a bit line in the semiconductor substrate using the mask layer as a mask;
forming on the bit line an insulating film that is penetrating the ONO film, defined by the mask layer, and thicker than the ONO film;
etching the top oxide film using as a mask a first sidewall layer provided on a sidewall of the insulating film on the ONO film; and
oxidizing the trap layer under a portion where the top oxide film is etched.
12. The method for manufacturing a semiconductor device according to claim 11 , wherein the mask layer is a silicon nitride film.
13. The method for manufacturing of a semiconductor device according to claim 11 , wherein the mask layer is a polysilicon film.
14. The method for manufacturing a semiconductor device according to claim 11 , wherein oxidizing the trap layer comprises oxidizing the trap layer through low temperature radical oxidation.
15. The method for manufacturing a semiconductor device according to claim 11 , wherein oxidizing the trap layer comprises entirely oxidizing the trap layer.
16. The method for manufacturing a semiconductor device according to claim 11 , wherein oxidizing the trap layer comprises oxidizing the trap layer with a portion of the trap layer remaining.
17. The method for manufacturing a semiconductor device according to claim 11 , wherein etching the top oxide film comprises etching the top oxide film so that part of the top oxide film remains.
18. The method for manufacturing a semiconductor device according to claim 17 , wherein an etching amount of the top oxide film is substantially equal to an oxidation amount of the trap layer.
19. The method for manufacturing a semiconductor device according to claim 11 , wherein etching the top oxide film comprises entirely etching the top oxide film.
20. The method for manufacturing a semiconductor device according to claim 19 , wherein a thickness of the top oxide film is substantially equal to an oxidation amount of the trap layer.