Semiconductor device comprising isolation trenches inducing different types of strain
View Patent ↗By forming isolation trenches of different types of intrinsic stress on the basis of separate process sequences, the strain characteristics of adjacent active semiconductor regions may be adjusted so as to obtain overall device performance. For example, highly stressed dielectric fill material including compressive and tensile stress may be appropriately provided in the respective isolation trenches in order to correspondingly adapt the charge carrier mobility of respective channel regions.
1. A semiconductor device, comprising:
a first active semiconductor region having at least one border formed by a first trench isolation structure including a first dielectric fill material having a first type of intrinsic stress, wherein said first trench isolation structure has a first trench width and said first type of intrinsic stress is one of a tensile type stress and a compressive type stress;
a second active semiconductor region having at least one border formed by a second trench isolation structure including a second dielectric fill material, said second dielectric fill material having a second type of intrinsic stress, wherein said second trench isolation structure has a second trench width, said first width is less than said second trench width, and said second type of intrinsic stress is of an opposite type from said first type of intrinsic stress; and
a third trench isolation structure having a third trench width that is greater than said first trench width, said third isolation structure comprising a third dielectric fill material having a third type of intrinsic stress.
2. The semiconductor device of claim 1 , further comprising a first transistor formed in said first active semiconductor region and a second transistor formed in said second active semiconductor region, said first and second transistors differing in at least one of conductivity type and transistor configuration.
3. The semiconductor device of claim 1 , wherein said first and second isolation trenches are oriented substantially perpendicular to each other.
4. The semiconductor device of claim 1 , wherein said third type of intrinsic stress is of a same type as and of a lesser magnitude than said first type of intrinsic stress.
5. The semiconductor device of claim 1 , wherein said third type of intrinsic stress is of a same type as and of a lesser magnitude than said second type of intrinsic stress.
6. The semiconductor device of claim 1 , wherein a magnitude of said first type of intrinsic stress is at least approximately 1 Giga Pascal.
7. The semiconductor device of claim 1 , wherein a magnitude of said second type of intrinsic stress is at least approximately 1 Giga Pascal.
8. The semiconductor device of claim 1 , wherein at least one of said first and second dielectric fill materials comprises silicon nitride.
9. The semiconductor device of claim 8 , wherein said first dielectric fill material comprises silicon dioxide.
10. The semiconductor device of claim 1 , wherein said third isolation structure is formed adjacent to both said first active semiconductor region and said second active semiconductor region, and wherein said third type of intrinsic stress is of a magnitude which is less than said first and second types of intrinsic stresses.
11. The semiconductor device of claim 10 , wherein said first and second dielectric fill materials comprise silicon nitride and said third dielectric fill material comprises silicon dioxide.
12. The semiconductor device of claim 1 , wherein said third trench isolation structure forms at least one additional border of said second active semiconductor region, and wherein said third trench isolation structure is oriented substantially perpendicular to said at least one border formed by said second trench isolation structure.
13. The semiconductor device of claim 12 , wherein said third type of intrinsic stress is of a same type as said second type of intrinsic stress.
14. The semiconductor device of claim 12 , wherein said third type of intrinsic stress is of an opposite type from said second type of intrinsic stress.