Transistor of a semiconductor device

1. A transistor of a semiconductor device, comprising:

a stack type gate comprising a tunnel oxide film, a floating gate having two sides with sidewalls, a dielectric film, and a control gate sequentially stacked on a semiconductor substrate;

a gate oxide film formed on the semiconductor substrate below the floating gate with respect to the tunnel oxide film, wherein the gate oxide film is formed along the boundary of a portion of a bottom and a side of the floating gate;

a first spacer formed to cover both sidewalls of the floating gate, the dielectric film, and the control gate; and

floating nitride films buried at gaps between the gate oxide film formed on the semiconductor substrate and the gate oxide film formed along a boundary of a portion of a bottom and a side of the floating gate,

wherein the floating nitride films serve as a trap center of a hot charge and store 1 bit charge, and wherein respective first sides at both sides of the floating gate contact the first spacer, respective second sides at both sides of the floating gate contact the gate oxide film, a width between the respective second sides is narrower than a width between the respective first sides, the bottom defines a plane that contacts the tunnel oxide film, and a face between the bottom and the second sides is inclined at a given tilt and contacts the gate oxide film.

2. The transistor of claim 1 , further comprising second spacers formed at the sides of the first spacers, the gate oxide film formed at a portion of the bottom and side of the floating gate, and the floating nitride film.

3. The transistor of claim 1 , wherein the bottom of the first spacer is lower than the top of the floating gate and higher than the bottom of the floating gate.

4. The transistor of claim 1 , wherein the bottom of the first spacer is lower than the top of the floating gate and higher than the bottom of the floating gate, and the face between the first side and the second side of the floating gate and the bottom of the first spacer is located on the same plane.

5. The transistor of claim 1 , wherein the floating nitride film has a right-angled triangle shape.

6. The transistor of claim 1 , further comprising a capping film formed on the control gate.

7. The transistor of claim 1 , further comprising a source/drain electrode formed in the semiconductor substrate at a lower side of the floating gate.

8. A transistor of a semiconductor device, comprising:

a stack type gate comprising a tunnel oxide film, a floating gate having first and second sides and sidewalls, a dielectric film, and a control gate sequentially stacked on a semiconductor substrate;

first spacers formed on sidewalls of a portion of the floating gate, the dielectric film, and the control gate;

a gate oxide film formed at a portion of a bottom and a side of the floating gate and on the semiconductor substrate;

floating nitride films in which gaps are formed between the gate oxide film formed at a portion of the bottom and side of the floating gate and the gate oxide film formed on the semiconductor substrate, wherein the floating nitride films are buried in the gaps; and

second spacers formed on sidewalls of the first spacers, the gate oxide film formed at a portion of the bottom and side of the floating gate, and the floating nitride film,

wherein respective first sides at both sides of the floating gate contact the first spacers, respective second sides at both sides of the floating gate contact the gate oxide film, a width between the respective second sides is narrower than a width between the respective first sides, the bottom of the floating gate defines a plane that contacts the tunnel oxide film, and a face between the bottom and the second sides is inclined at a given tilt and contacts the gate oxide film.

9. The transistor of claim 8 , wherein the bottom of the first spacers is lower than the top of the floating gate and higher than the bottom of the floating gate.

10. The transistor of claim 8 , wherein, the bottom of the first spacers is lower than the top of the floating gate and higher than the bottom of the floating gate, and the face between the first side and the second side of the floating gate and the bottom of the first spacers is located on the same plane.

11. The transistor of claim 8 , wherein the floating nitride film has a right-angled triangle shape.

12. The transistor of claim 8 , further comprising a capping film formed on the control gate.

13. The transistor of claim 8 , further comprising a source/drain electrode formed in the semiconductor substrate at a lower side of the floating gate.

14. A transistor of a semiconductor device, comprising:

a stack type gate comprising a tunnel oxide film, a floating gate having first and second sides and sidewalls, a dielectric film, and a control gate sequentially stacked on a semiconductor substrate;

a first spacer formed on sidewalls of a portion of the floating gate, the dielectric film, and the control gate;

a thermal oxide film formed on the semiconductor substrate at a bottom of the first side of the floating gate; a gate oxide film formed at a portion of the bottom and a side of the first side of the floating gate and on the thermal oxide film, wherein the gate oxide film is also formed at a portion of the bottom and a side of a second side of the floating gate and on the semiconductor substrate at the bottom of the second side of the floating gate;

floating nitride films in which gaps are formed between the gate oxide film formed at a portion of the bottom and the side of the second side of the floating gate and the gate oxide film formed on the semiconductor substrate at the bottom of the second side of the floating gate, wherein the floating nitride films are buried in the gaps; and

second spacers formed on the first spacer and the thermal oxide film at the first side of the floating gate and formed on sidewalls of the first spacer at the second side of the floating gate, the gate oxide film formed at the bottom and side of the floating gate and the floating nitride film,

wherein at the second side of the floating gate, the first side of the floating gate contacts the first spacers, the second side of the floating gate contacts the gate oxide film, the bottom defines a plane that contacts the tunnel oxide film, and a face between the bottom and the second side is inclined at a given tilt and contacts the gate oxide film.

15. The transistor of claim 14 , wherein the bottom of the first spacer is lower than the top of the floating gate and higher than the bottom of the floating gate.

16. The transistor of claim 14 , wherein the gate oxide film contacts the bottom of the first spacer, the face between the first side and the second side, the second side, the face between the bottom of the floating gate and the second side, and the tunnel oxide film.

17. The transistor of claim 14 , wherein the floating nitride film has a right-angled triangle shape.

18. The transistor of claim 14 , further comprising a capping film formed on the control gate.

19. The transistor of claim 14 , further comprising a source/drain electrode formed in the semiconductor substrate at a lower side of the floating gate.