Method of forming a semiconductor device and structure thereof
View Patent ↗In one embodiment, a method for forming a semiconductor device is described. A semiconductor substrate has a first portion and a second portion. A first dielectric layer formed over the first portion of the semiconductor substrate and a second dielectric layer is formed over the second portion of the semiconductor substrate. A cap that may include silicon, such as polysilicon, is formed over the first dielectric layer. A first electrode layer is formed over the cap and a second electrode layer is formed over the second dielectric.
1. A method for forming a semiconductor device comprising:
providing a semiconductor substrate having a first portion and a second portion;
forming a first dielectric layer over the first portion of the semiconductor substrate;
forming a second dielectric layer over the second portion of the semiconductor substrate;
forming a cap over the first dielectric;
forming a first gate electrode layer over the cap; and
forming a second gate electrode layer over the second dielectric layer, but not over the first gate electrode layer.
2. The method of claim 1 , wherein forming the first dielectric layer and forming the second dielectric layer comprise forming different dielectric materials.
3. The method of claim 1 , wherein forming the first dielectric layer and forming the second dielectric layer comprise forming the same dielectric material.
4. The method of claim 1 , wherein the forming the first dielectric layer comprises forming a field oxide.
5. The method of claim 1 , wherein forming the first dielectric layer comprises forming a gate dielectric.
6. The method of claim 1 , wherein forming the second dielectric layer comprises forming a dielectric layer with a high dielectric constant.
7. The method of claim 1 , wherein forming the second dielectric layer comprises forming a stack of at least two dielectric layers, wherein at least one of the at least two dielectric layers has a dielectric constant greater than approximately 4.
8. The method of claim 1 , wherein forming the cap comprises forming a polysilicon cap.
9. The method of claim 1 , wherein
the semiconductor substrate further comprises a third portion; and
the method further comprises:
forming a third dielectric layer over the third portion;
forming the second gate electrode layer over the third dielectric layer; and
forming a third gate electrode layer over the second gate electrode layer.
10. The method of claim 9 , wherein forming the third dielectric layer and forming the second dielectric layer comprise forming the same dielectric material.
11. The method of claim 9 , wherein forming the third dielectric layer and forming the second dielectric layer comprise forming different dielectric materials.
12. The method of claim 1 , wherein
the semiconductor substrate further comprises a fourth portion; and
the method further comprises:
forming an isolation region in the fourth portion;
forming the cap over the fourth portion; and
forming the second gate electrode layer over the cap.
13. A method for forming a semiconductor device comprising:
providing a semiconductor substrate having a first portion and a second portion;
forming a first dielectric over the first portion of the semiconductor substrate, wherein the first dielectric has a high dielectric constant;
forming a second dielectric over the second portion of the semiconductor substrate;
forming a cap over the second dielectric, wherein the cap comprises silicon;
forming a first gate electrode over the first dielectric, wherein the first gate electrode comprises metal; and
forming a second gate electrode over the cap but not over the first gate electrode, wherein the second gate electrode comprises silicon.
14. The method of claim 13 , wherein forming the first dielectric and forming the second dielectric comprise forming different dielectric materials.
15. The method of claim 13 , wherein forming the first dielectric and forming the second dielectric comprise forming the same dielectric material.
16. The method of claim 13 , wherein forming the first dielectric comprises forming a gate dielectric.
17. The method of claim 13 , wherein forming the first dielectric, wherein the first dielectric has the high dielectric constant comprise forming the first dielectric, wherein the first dielectric has a dielectric constant greater than approximately 4.
18. A semiconductor device comprising:
a semiconductor substrate comprising a first portion and a second portion;
a first dielectric layer over the first portion;
a cap over the first dielectric layer;
a first gate electrode layer over the cap;
a second dielectric layer over the second portion; and
a second gate electrode layer over the second dielectric layer wherein the first gate electrode layer and the second gate electrode layer do not overlie each other.
19. The semiconductor device of claim 18 , wherein
the cap comprises polysilicon;
the first gate electrode layer is different than the second gate electrode layer; and
and the first dielectric layer is different than the second dielectric layer.
20. The semiconductor device of claim 19 , wherein the second dielectric layer has a dielectric constant greater than approximately 4.
21. The method of claim 13 , wherein:
the forming the first gate electrode further comprises forming the first gate electrode after forming the cap; and
the forming the second gate electrode further comprises forming the second gate electrode after forming the first gate electrode.