Semiconductor device comprising a high dielectric constant insulating film including nitrogen

1. A semiconductor device comprising:

a first gate electrode formed in a first region on a semiconductor substrate with a first gate insulating film sandwiched therebetween; and

a second gate electrode formed in a second region on the semiconductor substrate with a second gate insulating film sandwiched therebetween,

the first gate insulating film including a first high dielectric constant insulating film with a first nitrogen concentration,

the second gate insulating film including a second high dielectric constant insulating film with a second nitrogen concentration higher than the first nitrogen concentration, wherein

the first gate electrode includes a first metal layer and a first silicon layer formed on the first metal layer, and

the second gate electrode includes a second silicon layer.

2. The semiconductor device of claim 1 , wherein the second high dielectric constant insulating film has a smaller thickness than the first high dielectric constant insulating film.

3. The semiconductor device of claim 1 ,

wherein the first gate insulating film includes a first interface layer formed between the semiconductor substrate and the first high dielectric constant insulating film, and

the second gate insulating film includes a second interface layer formed between the semiconductor substrate and the second high dielectric constant insulating film.

4. The semiconductor device of claim 1 , wherein the first gate electrode includes a different conducting material from the second gate electrode.

5. The semiconductor device of claim 1 , wherein the first metal layer is made of TiN.

6. The semiconductor device of claim 1 ,

wherein the first gate electrode includes a second metal layer formed between the first metal layer and the first silicon layer, and

the second gate electrode includes a third metal layer formed between the second gate insulating film and the second silicon layer.

7. The semiconductor device of claim 6 , wherein the second metal layer and the third metal layer are made of TaN.

8. The semiconductor device of claim 1 , wherein the first high dielectric constant insulating film and the second high dielectric constant insulating film are made of HfSiON.

9. The semiconductor device of claim 1 ,

wherein the first gate electrode is a gate electrode of a P-type MISFET, and

the second gate electrode is a gate electrode of an N-type MISFET.

10. The semiconductor device of claim 1 , wherein the first high dielectric constant insulating film and the second high dielectric constant insulating film are made of hafnium oxide including nitrogen.

11. The semiconductor device of claim 1 , wherein the second gate electrode includes a second metal layer formed between the second gate insulating film and the second silicon layer.

12. The semiconductor device of claim 1 ,

wherein the first high dielectric constant insulating film includes a first HfSiO film and a first HfSiON layer formed on the first HfSiO film,

the second high dielectric constant insulating film includes a second HfSiO film and a second HfSiON layer formed on the second HfSiO film, and

a nitrogen concentration of the second HfSiON layer is higher than a nitrogen concentration of the first HfSiON layer.

13. The semiconductor device of claim 1 ,

wherein first extension regions of a first conductivity-type are formed in portions of the first region disposed on both sides of the first gate electrode, and

second extension regions of a second conductivity-type are formed in portions of the second region disposed on both sides of the second gate electrode.

14. The semiconductor device of claim 1 , further comprising:

a first silicide layer formed on the first gate electrode; and

a second silicide layer formed on the second gate electrode.

15. The semiconductor device of claim 1 , wherein a peak of the first nitrogen concentration in the first high dielectric constant insulating film is 5 through 20 atomic %.

16. The semiconductor device of claim 1 , wherein a peak of the second nitrogen concentration in the second high dielectric constant insulating film is 5 through 40 atomic %.

17. The semiconductor device of claim 1 , further comprising:

first insulating sidewall spacers formed on the side faces of the first gate electrode; and

second insulating sidewall spacers formed on the side faces of the second gate electrode,

wherein each of the first insulating sidewall spacers is composed of a first inner spacer in an L shape and a first outer spacer, and

each of the second insulating sidewall spacers is composed of a second inner spacer in an L shape and a second outer spacer.

18. The semiconductor device of claim 17 ,

wherein each of the first insulating sidewall spacers is formed on the side faces of the first gate electrode with an first insulating offset spacer sandwiched therebetween, and

each of the second insulating sidewall spacers is formed on the side faces of the second gate electrode with an second insulating offset spacer sandwiched therebetween.

19. The semiconductor device of claim 3 , wherein the first interface layer and the second interface layer are made of SiON.

20. The semiconductor device of claim 1 , further comprising:

a first modified layer formed in a surface portion of the first high dielectric constant insulating film; and

a second modified layer formed in a surface portion of the second high dielectric constant insulating film,

wherein the first modified layer and the second modified layer include nitrogen, and a nitrogen concentration of the second modified layer is higher than a nitrogen concentration of the first modified layer.