Structure and formation method of FinFET device
Structures and formation methods of a semiconductor device structure are provided. The semiconductor device structure includes a semiconductor substrate and a fin structure over the semiconductor substrate. The semiconductor device structure also includes a gate stack over a portion of the fin structure, and the fin structure includes an intermediate portion under the gate stack and upper portions besides the intermediate portion. The semiconductor device structure further includes a contact layer over the fin structure. The contact layer includes a metal material, and the upper portions of the fin structure also include the metal material.
1. A semiconductor device structure, comprising:
a semiconductor substrate;
a fin structure over the semiconductor substrate;
a gate stack over the fin structure, wherein the fin structure includes an intermediate portion under the gate stack, upper portions besides the intermediate portion, and a lower portion below the upper portions and the intermediate portion;
a contact layer over the fin structure, wherein the contact layer comprises a metal material, and the upper portions of the fin structure also comprise the metal material; and
a carbon-containing layer between the semiconductor substrate and the fin structure, wherein the carbon-containing layer surrounds the lower portion of the fin structure.
2. The semiconductor device structure as claimed in claim 1 , wherein the metal material comprises tin, lead, or a combination thereof.
3. The semiconductor device structure as claimed in claim 1 , wherein a concentration of the metal material in each of the upper portions gradually decreases along a direction away from an interface between the fin structure and the contact layer.
4. The semiconductor device structure as claimed in claim 1 , wherein the fin structure comprises germanium.
5. The semiconductor device structure as claimed in claim 4 , wherein the contact layer further comprises germanium.
6. The semiconductor device structure as claimed in claim 5 , wherein a concentration of germanium in the contact layer gradually decreases along a direction away from an interface between the fin structure and the contact layer.
7. The semiconductor device structure as claimed in claim 1 , wherein the lower portion of the fin structure further comprises carbon.
8. The semiconductor device structure as claimed in claim 7 , wherein a concentration of carbon in the lower portion gradually decreases along a direction away from an interface between the fin structure and the carbon-containing layer.
9. The semiconductor device structure as claimed in claim 1 , further comprising a semiconductor blocking layer between the intermediate portion of the fin structure and the gate stack.
10. The semiconductor device structure as claimed in claim 1 , wherein the contact layer surrounds the upper portions of the fin structure.
11. A semiconductor device structure, comprising:
a semiconductor substrate;
a germanium-containing fin structure over the semiconductor substrate;
a metal gate stack over a portion of the germanium-containing fin structure; and
a carbon-containing layer between the semiconductor substrate and the germanium-containing fin structure, wherein the carbon-containing layer surrounds a lower portion of the germanium-containing fin structure.
12. The semiconductor device structure as claimed in claim 11 , further comprising a contact layer over the germanium-containing fin structure, wherein the contact layer comprises a metal material, and another portion of the germanium-containing fin structure that is under the contact layer also comprises the metal material.
13. The semiconductor device structure as claimed in claim 12 , wherein the metal material comprises tin, lead, or a combination thereof.
14. The semiconductor device structure as claimed in claim 11 , further comprising:
a dielectric layer over the contact layer; and
a conductive contact in the dielectric layer and is in electrical contact with the contact layer.
15. The semiconductor device structure as claimed in claim 11 , further comprising a semiconductor blocking layer between the germanium-containing fin structure and the metal gate stack, wherein the semiconductor blocking layer comprises a semiconductor material.
16. A method for forming a semiconductor device structure, comprising:
forming a carbon-containing layer over a semiconductor substrate;
forming a fin structure over the semiconductor substrate, wherein the carbon-containing layer surrounds a lower portion of the fin structure;
forming a gate stack over the fin structure;
forming a contact layer over the fin structure, wherein the contact layer comprises a metal material; and
driving a portion of the metal material from the contact layer into the fin structure.
17. The method for forming a semiconductor device structure as claimed in claim 16 , wherein the formation of the carbon-containing layer over the semiconductor substrate is performed before the fin structure is formed.
18. The method for forming a semiconductor device structure as claimed in claim 16 , wherein the portion of the metal material is driven into the fin structure using a thermal operation.
19. The method for forming a semiconductor device structure as claimed in claim 16 , further comprising forming a semiconductor blocking layer over the fin structure before the gate stack is formed.
20. The method for forming a semiconductor device structure as claimed in claim 19 , further comprising:
oxidizing a portion of the semiconductor blocking layer not covered by the gate stack; and
removing the oxidized portion of the semiconductor blocking layer before the contact layer is formed.