Semiconductor device
View Patent ↗A semiconductor device 100 comprises a silicon substrate 102 , an N-type MOSFET 118 including a high concentration-high dielectric constant film 108 b formed on the silicon substrate 102 and a polycrystalline silicon film 114 , and a P-type MOSFET 120 including a low concentration-high dielectric constant film 108 a and a polycrystalline silicon film 114 formed on the semiconductor substrate 102 to be juxtaposed to the N-type MOSFET 118 . The low concentration-high dielectric constant film 108 a and the high concentration-high dielectric constant film 108 b are composed of a material containing one or more element (s) selected from a group consisting of Hf and Zr. The concentration of the above-described metallic element contained in the low concentration-high dielectric constant film 108 a is lower than that contained in the high concentration-high dielectric constant film 108 b.
1. A semiconductor device, comprising:
a semiconductor substrate;
an N-type MOSFET including:
a first gate insulating film, formed on said semiconductor substrate, and composed of a first high dielectric constant film including one or more metallic element(s) selected from a group consisting of Hf and Zr; and
a first gate electrode, disposed on said first gate insulating film to contact with said first high dielectric constant film, and composed of a polycrystalline silicon film; and
a P-type MOSFET including:
a second gate insulating film, formed on said semiconductor substrate to be juxtaposed to said N-type MOSFET, and composed of a second high dielectric constant film containing one or more metallic element (s) selected from a group consisting of Hf and Zr; and
a second gate electrode, disposed on said second gate insulating film to contact with said second high dielectric constant film, and composed of a polycrystalline silicon film,
wherein a concentration of said metallic element in said second high dielectric constant film is lower than a concentration of said metallic element in said first high dielectric constant film.
2. The semiconductor device according to claim 1 , wherein a concentration of said metallic element at least at an interface contacting with said polycrystalline silicon film in said second high dielectric constant film is lower than a concentration of said metallic element at an interface contacting with said polycrystalline silicon film in said first high dielectric constant film.
3. The semiconductor device according to claim 2 , wherein an average concentration of said metallic element in said second high dielectric constant film is lower than an average concentration of said metallic element in said first high dielectric constant film.
4. The semiconductor device according to claim 2 , wherein said first gate insulating film of said N-type MOSFET further includes a silicon oxide film provided between said semiconductor substrate and said first high dielectric constant film, and wherein said second gate insulating film of said P-type MOSFET further includes a silicon oxide film provided between said semiconductor substrate and said second high dielectric constant film.
5. The semiconductor device according to claim 2 , wherein, in said first gate electrode of said N-type MOSFET, said polycrystalline silicon film includes an N-type impurity, and wherein, in said second gate electrode of said P-type MOSFET, said polycrystalline silicon film includes a P-type impurity.
6. The semiconductor device according to claim 1 , wherein an average concentration of said metallic element in said second high dielectric constant film is lower than an average concentration of said metallic element in said first high dielectric constant film.
7. The semiconductor device according to claim 6 , wherein said first gate insulating film of said N-type MOSFET further includes a silicon oxide film provided between said semiconductor substrate and said first high dielectric constant film, and wherein said second gate insulating film of said P-type MOSFET further includes a silicon oxide film provided between said semiconductor substrate and said second high dielectric constant film.
8. The semiconductor device according to claim 6 , wherein, in said first gate electrode of said N-type MOSFET, said polycrystalline silicon film includes an N-type impurity, and wherein, in said second gate electrode of said P-type MOSFET, said polycrystalline silicon film includes a P-type impurity.
9. The semiconductor device according to claim 1 , wherein said first dielectric constant film is a single layer.
10. The semiconductor device according to claim 1 , wherein said second dielectric constant film is a single layer.