Method to form stacked germanium nanowires and stacked III-V nanowires
View Patent ↗A first sacrificial gate structure is formed over a first fin stack and a second sacrificial gate structure is formed over a second fin stack. The first and second fin stacks include alternating layers of a III-V compound semiconductor material portion and a germanium material portion. Source/drain structures are formed adjacent the first and second sacrificial gate structures. The first sacrificial structure is removed to provide a first gate cavity. Exposed III-V compound semiconductor portions in the first gate cavity are removed to suspend a portion of each germanium material portion. A first functional gate structure is formed in the first gate cavity. The second sacrificial structure is removed to provide a second gate cavity. Exposed germanium material portions are removed to suspend a portion of each III-V compound semiconductor material portion of the second fin stack. A second functional gate structure is formed in the second gate cavity.
1. A method of forming a semiconductor structure, said method comprising:
forming a first sacrificial gate structure straddling over a portion of a first fin stack and a second sacrificial gate structure straddling over a portion of a second fin stack, wherein said first and second fin stacks comprise alternating layers of a III-V compound semiconductor material portion and a germanium material portion;
forming a first source/drain structure on other portions of said first fin stack and adjacent said first sacrificial gate structure and a second source/drain structure on other portions of said second fin stack and adjacent said second sacrificial gate structure;
removing said first sacrificial structure selective to said second sacrificial gate structure to provide a first gate cavity;
removing each exposed III-V compound semiconductor portion of said first fin stack in said first gate cavity to provide suspended germanium nanowires that comprise a portion of each germanium material portion of said first fin stack;
forming a first functional gate structure in said first gate cavity and surrounding each suspended germanium nanowire;
removing said second sacrificial structure selective to said first functional gate structure to provide a second gate cavity;
removing each exposed germanium material portion of said second fin stack in said second gate cavity to provide suspended III-V compound semiconductor nanowires that comprise a portion of each III-V compound semiconductor material portion of said second fin stack; and
forming a second functional gate structure in said second gate cavity and surrounding each suspended III-V compound semiconductor nanowire.
2. The method of claim 1 , wherein said first fin stack is formed on a first portion of a germanium layer and said second fin stack is formed on a second portion of said germanium layer and wherein said first and second fin stacks comprise alternating layers, of from bottom to top, of said III-V compound semiconductor material portion and said germanium material portion.
3. The method of claim 2 , wherein during said removing each exposed germanium material portion in said second device region, a recessed region is provided in said germanium layer, and wherein a lower portion of said second functional gate structure fills said recessed region.
4. The method of claim 1 , wherein said first fin stack is formed on a first portion of a III-V compound semiconductor layer and said second fin stack is formed on a second portion of said III-V compound semiconductor layer and wherein said first and second fin stacks comprise alternating layers, of from bottom to top, of said germanium material portion and said III-V compound semiconductor material portion.
5. The method of claim 4 , wherein during said removing each exposed III-V compound semiconductor portion in said first device region, a recessed region is provided in said III-V compound semiconductor layer, and wherein a lower portion of said first functional gate structure fills said recessed region.
6. The method of claim 1 , wherein said first fin stack and said second fin stack are formed by:
providing a material stack comprising alternating layers of a III-V compound semiconductor material and a germanium material; and
patterning said material stack.
7. The method of claim 6 , wherein said providing said material stack comprises epitaxial deposition said alternating layers of said III-V compound semiconductor material and said germanium material.
8. The method of claim 6 , wherein said patterning comprises a sidewall image transfer process.
9. The method of claim 1 , further comprising forming a dielectric spacer on sidewall surfaces of said first sacrificial gate structure and said second sacrificial gate structure prior to forming said first and second source/drain structures.
10. The method of claim 1 , wherein said first source/drain structure and said second source/drain structure are formed utilizing at least an epitaxial growth process.
11. A method of forming a semiconductor structure, said method comprising:
forming a first sacrificial gate structure straddling over a portion of a first fin stack and a second sacrificial gate structure straddling over a portion of a second fin stack, wherein said first and second fin stacks comprise alternating layers of a III-V compound semiconductor material portion and a germanium material portion;
forming a first source/drain structure on other portions of said first fin stack and adjacent said first sacrificial gate structure and a second source/drain structure on other portions of said second fin stack and adjacent said second sacrificial gate structure;
removing said second sacrificial structure selective to said first sacrificial gate structure to provide a second gate cavity;
removing each exposed germanium material portion of said second fin stack in said second gate cavity to provide suspended III-V compound semiconductor nanowires that comprise a portion of each III-V compound semiconductor material portion of said second fin stack;
forming a second functional gate structure in said second gate cavity and surrounding each suspended III-V compound semiconductor nanowire;
removing said first sacrificial structure selective to said second functional gate structure to provide a first gate cavity;
removing each exposed III-V compound semiconductor portion of said first fin stack in said first gate cavity to provide suspended germanium nanowires that comprise a portion of each germanium material portion of said first fin stack; and
forming a first functional gate structure in said first gate cavity and surrounding each suspended germanium nanowire.
12. The method of claim 11 , wherein said first fin stack is formed on a first portion of a germanium layer and said second fin stack is formed on a second portion of said germanium layer and wherein said first and second fin stacks comprise alternating layers, of from bottom to top, of said III-V compound semiconductor material portion and said germanium material portion.
13. The method of claim 12 , wherein during said removing each exposed germanium material portion in said second device region, a recessed region is provided in said germanium layer, and wherein a lower portion of said second functional gate structure fills said recessed region.
14. The method of claim 11 , wherein said first fin stack is formed on a first portion of a III-V compound semiconductor layer and said second fin stack is formed on a second portion of said III-V compound semiconductor layer and wherein said first and second fin stacks comprise alternating layers, of from bottom to top, of said germanium material portion and said III-V compound semiconductor material portion.
15. The method of claim 14 , wherein during said removing each exposed III-V compound semiconductor portion in said first device region, a recessed region is provided in said III-V compound semiconductor layer, and wherein a lower portion of said first functional gate structure fills said recessed region.
16. The method of claim 11 , wherein said first fin stack and said second fin stack are formed by
providing a material stack comprising alternating layers of a III-V compound semiconductor material and a germanium material; and
patterning said material stack.
17. The method of claim 16 , wherein said providing said material stack comprises epitaxial deposition said alternating layers of said III-V compound semiconductor material and said germanium material.
18. The method of claim 16 , wherein said patterning comprises a sidewall image transfer process.
19. The method of claim 11 , further comprising forming a dielectric spacer on sidewall surfaces of said first sacrificial gate structure and said second sacrificial gate structure prior to forming said first and second source/drain structures.
20. The method of claim 11 , wherein said first source/drain structure and said second source/drain structure are formed utilizing at least an epitaxial growth process.