Semiconductor device and method for fabricating the same
View Patent ↗A semiconductor device includes: a first gate insulating film on a first region of a semiconductor substrate; a first gate electrode on the first gate insulating film; a second gate insulating film on a second region of the semiconductor substrate; and a second gate electrode on the second gate insulating film. The first gate insulating film includes a first insulating film composed of a first material containing a first metal, and the second gate insulating film includes a second insulating film composed of the first material and a second material containing a second metal.
1. A semiconductor device comprising:
a first gate insulating film formed on a first region of a semiconductor substrate;
a first gate electrode formed on the first gate insulating film;
a second gate insulating film formed on a second region of the semiconductor substrate; and
a second gate electrode formed on the second gate insulating film,
wherein the first gate insulating film includes a first insulating film composed of a first material containing a first metal, and
the second gate insulating film includes a second insulating film composed of the first material and a second material containing a second metal.
2. The semiconductor device of claim 1 , wherein the second insulating film has a higher concentration of the second metal in an upper portion than in a lower portion of the second insulating film.
3. The semiconductor device of claim 2 , wherein
the first gate insulating film is thinner than the second gate insulating film.
4. The semiconductor device of claim 2 , wherein
the first metal is hafnium, zirconium, or yttrium.
5. The semiconductor device of claim 2 , wherein
a MISFET of first conductivity type is provided in the first region, and
a MISFET of second conductivity type is provided in the second region, and
the second metal is lanthanum, scandium, erbium, or strontium.
6. The semiconductor device of claim 2 , wherein
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film and a first silicon film on the first conductive film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film and a second silicon film on the second conductive film, and
the second conductive film is made of a material which is smaller in work function than the first conductive film.
7. The semiconductor device of claim 6 , wherein
the first conductive film is titanium nitride, ruthenium, or molybdenum aluminum nitride, and
the second conductive film is tantalum nitride or tantalum carbide.
8. The semiconductor device of claim 2 , wherein
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film and a first silicon film on the first conductive film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film and a second silicon film on the second conductive film,
the first conductive film and the second conductive film are made of the same material, and
the first conductive film is greater in thickness than the second conductive film.
9. The semiconductor device of claim 2 , wherein
an n-type MISFET is provided in the first region,
a p-type MISFET is provided in the second region, and
the second metal is aluminum.
10. The semiconductor device of claim 2 , wherein
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film and a first silicon film on the first conductive film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film and a second silicon film on the second conductive film, and
the second conductive film is made of a material which is greater in work function than the first conductive film.
11. The semiconductor device of claim 10 , wherein
the first conductive film is tantalum nitride or tantalum carbide, and
the second conductive film is titanium nitride, ruthenium, or molybdenum aluminum nitride.
12. The semiconductor device of claim 2 , wherein
the first metal is hafnium, zirconium, or yttrium, and
the second metal is lanthanum, scandium, erbium, or strontium.
13. The semiconductor device of claim 2 , wherein
the first metal is hafnium, zirconium, or yttrium, and
the second metal is aluminum.
14. The semiconductor device of claim 2 , wherein
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film, and
the first conductive film and the second conductive film are made of the same material.
15. The semiconductor device of claim 2 , wherein
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film, and
the first conductive film and the second conductive film are made of different materials.
16. The semiconductor device of claim 2 , wherein
a p-type MISFET is provided in the first region,
an n-type MISFET is provided in the second region,
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film, and
the second conductive film is made of a material which is smaller in work function than the first conductive film.
17. The semiconductor device of claim 2 , wherein
an n-type MISFET is provided in the first region,
a p-type MISFET is provided in the second region,
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film, and
the second conductive film is made of a material which is greater in work function than the first conductive film.
18. The semiconductor device of claim 1 , wherein the first gate insulating film is thinner than the second gate insulating film.
19. The semiconductor device of claim 1 , wherein the first material is different in dielectric constant from the second material.
20. The semiconductor device of claim 1 , wherein the first metal is hafnium, zirconium, or yttrium.
21. The semiconductor device of claim 1 , wherein
a MISFET of first conductivity type is provided in the first region, and
a MISFET of second conductivity type is provided in the second region.
22. The semiconductor device of claim 1 , wherein
a p-type MISFET is provided in the first region,
an n-type MISFET is provided in the second region, and
the second metal is lanthanum, scandium, erbium, or strontium.
23. The semiconductor device of claim 1 , wherein
a p-type MISFET is provided in the first region,
an n-type MISFET is provided in the second region,
the first material is hafnium silicate nitride, and
the second material is lanthanum oxide.
24. The semiconductor device of claim 1 , wherein
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film and a first silicon film on the first conductive film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film and a second silicon film on the second conductive film, and
the second conductive film is made of a material which is smaller in work function than the first conductive film.
25. The semiconductor device of claim 24 , wherein
the first conductive film is titanium nitride, ruthenium, or molybdenum aluminum nitride, and
the second conductive film is tantalum nitride or tantalum carbide.
26. The semiconductor device of claim 1 , wherein
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film and a first silicon film on the first conductive film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film and a second silicon film on the second conductive film,
the first conductive film and the second conductive film are made of the same material, and
the first conductive film is greater in thickness than the second conductive film.
27. The semiconductor device of claim 1 , wherein
an n-type MISFET is provided in the first region,
a p-type MISFET is provided in the second region, and
the second metal is aluminum.
28. The semiconductor device of claim 1 , wherein
an n-type MISFET is provided in the first region,
a p-type MISFET is provided in the second region,
the first material is hafnium silicate nitride, and
the second material is aluminum oxide.
29. The semiconductor device of claim 1 , wherein
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film and a first silicon film on the first conductive film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film and a second silicon film on the second conductive film, and
the second conductive film is made of a material which is greater in work function than the first conductive film.
30. A semiconductor device of claim 29 , wherein
the first conductive film is tantalum nitride or tantalum carbide, and
the second conductive film is titanium nitride, ruthenium, or molybdenum aluminum nitride.
31. The semiconductor device of claim 1 , wherein
the first gate insulating film includes a first interface layer under the first insulating film, and
the second gate insulating film includes a second interface layer under the second insulating film.
32. The semiconductor device of claim 1 , further comprising:
a first silicide layer on the first gate electrode; and
a second silicide layer on the second gate electrode.
33. The semiconductor device of claim 1 , wherein
the first metal is hafnium, zirconium, or yttrium, and
the second metal is lanthanum, scandium, erbium, or strontium.
34. The semiconductor device of claim 33 , wherein
a p-type MISFET is provided in the first region,
an n-type MISFET is provided in the second region,
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film, and
the second conductive film is made of a material which is smaller in work function than the first conductive film.
35. The semiconductor device of claim 1 , wherein
the first metal is hafnium, zirconium, or yttrium, and
the second metal is aluminum.
36. The semiconductor device of claim 35 , wherein
an n-type MISFET is provided in the first region,
a p-type MISFET is provided in the second region,
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film, and
the second conductive film is made of a material which is greater in work function than the first conductive film.
37. The semiconductor device of claim 1 , wherein
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film, and
the first conductive film and the second conductive film are made of the same material.
38. The semiconductor device of claim 1 , wherein
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film, and
the first conductive film and the second conductive film are made of different materials.
39. The semiconductor device of claim 1 , wherein
a p-type MISFET is provided in the first region,
an n-type MISFET is provided in the second region,
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film, and
the second conductive film is made of a material which is smaller in work function than the first conductive film.
40. The semiconductor device of claim 1 , wherein
an n-type MISFET is provided in the first region,
a p-type MISFET is provided in the second region,
the first gate electrode includes a first conductive film formed in contact with the first gate insulating film,
the second gate electrode includes a second conductive film formed in contact with the second gate insulating film, and
the second conductive film is made of a material which is greater in work function than the first conductive film.
41. The semiconductor device of claim 1 , wherein
the first insulating film does not contain the second metal.
42. The semiconductor device of claim 1 , further comprising:
a first extension region of first conductivity type formed extending laterally from the first gate electrode in the first region such that the first extension region overlaps with an edge of the first electrode from an underside of the first gate electrode; and
a second extension region of second conductivity type formed extending laterally from the second gate electrode in the second region such that the second extension region overlaps with an edge of the second gate electrode from an underside of the second gate electrode.
43. The semiconductor device of claim 1 , further comprising:
a first sidewall which is formed over a side face of the first gate electrode and includes an L-shaped first inner sidewall and a first outer sidewall on the first inner sidewall; and
a second sidewall which is formed over a side face of the second gate electrode and includes an L-shaped second inner sidewall and a second outer sidewall on the second inner sidewall.
44. The semiconductor device of claim 43 , wherein
the first sidewall is formed on an I-shaped first offset spacer on the side face of the first gate electrode, and
the second sidewall is formed on an I-shaped second offset spacer on the side face of the second gate electrode.
45. The semiconductor device of claim 1 , wherein
a p-type MISFET is provided in one of the first region and the second region and an n-type MISFET is provided in the other of the first region and the second region,
the p-type MISFET has an effective work function of 4.85 or larger, and
the n-type MISFET has an effective work function of 4.25 or smaller.