Replacement gate structure for enhancing conductivity

• US 9,450,072 B2
• Filed: 10/21/2014
• Issued: 09/20/2016
• Est. Priority Date: 06/18/2014
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: GlobalFoundries, Inc.
• Inventors: Chou, Anthony I., Kumar, Arvind, Lee, Sungjae
• Primary Examiner(s): Toledo, Fernando L
• Assistant Examiner(s): Newton, Valerie N
• Application Number:
  US14/519,615
• Publication Number:
  US 20150372109A1
• Time in Patent Office: 700 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02107 Forming insulating materials on a substrate
• CPC Class Codes: H01L 21/28132 conducting part of electrode is difined by a sidewall spacer or a similar technique, e.g. oxidation under mask, plating
• CPC Class Codes: H01L 21/28158 Making the insulator
• CPC Class Codes: H01L 21/283 Deposition of conductive or insulating materials for electrodes conducting electric current
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/3205 Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers manufacture of electrodes H01L21/28
• CPC Class Codes: H01L 21/32133 by chemical means only
• CPC Class Codes: H01L 21/32139 using masks
• CPC Class Codes: H01L 21/823431 with a particular manufacturing method of transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 21/82345 gate conductors with different gate conductor materials or different gate conductor implants, e.g. dual gate structures
• CPC Class Codes: H01L 21/823821 with a particular manufacturing method of transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 21/823842 gate conductors with different gate conductor materials or different gate conductor implants, e.g. dual gate structures
• CPC Class Codes: H01L 21/845 including field-effect transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 27/0886 including transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 27/1211 combined with field-effect transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 29/401 Multistep manufacturing processes
• CPC Class Codes: H01L 29/4232 with insulated gate
• CPC Class Codes: H01L 29/42356 Disposition, e.g. buried gate electrode H01L29/42324 and H01L29/4234 take precedence
• CPC Class Codes: H01L 29/4238 characterised by the surface lay-out
• CPC Class Codes: H01L 29/4958 with a multiple layer structure
• CPC Class Codes: H01L 29/51 : Insulating materials associated therewith for MIS structures on thin film semiconductor H01L29/4908
• CPC Class Codes: H01L 29/517 : the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/518 : the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: H01L 29/66545 : using a dummy, i.e. replacement gate in a process wherein at least a part of the final gate is self aligned to the dummy gate
• CPC Class Codes: H01L 29/66795 : with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 29/6681 : using dummy structures having essentially the same shape as the semiconductor body, e.g. to provide stability
• CPC Class Codes: H01L 29/785 : having a channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET

Abstract

After formation of a gate cavity straddling at least one semiconductor material portion, a gate dielectric layer and at least one work function material layer is formed over the gate dielectric layer. The at least one work function material layer and the gate dielectric layer are patterned such that remaining portions of the at least one work function material layer are present only in proximity to the at least one semiconductor material portion. A conductive material having a greater conductivity than the at least one work function material layer is deposited in remaining portions of the gate cavity. The conductive material portion within a replacement gate structure has the full width of the replacement gate structure in regions from which the at least one work function material layer and the gate dielectric layer are removed.

Claims

1. A method of forming a semiconductor structure comprising:

forming a planarization dielectric layer over a semiconductor material portion provided on a substrate;

forming a gate cavity within a planarization dielectric layer, said gate cavity straddling said semiconductor material portion;

forming a stack of a gate dielectric layer and a work function material layer in said gate cavity;

patterning said stack of said gate dielectric layer and said work function material layer, wherein portions of a topmost surface of said substrate and sidewalls of said planarization dielectric layer are physically exposed after patterning said stack; and

forming a conductive material portion on a remaining portion of said work function material layer and directly on said physically exposed portions of sidewalls of said planarization dielectric layer and said top surface of said substrate.

2. The method of claim 1, further comprising:

forming a disposable gate structure straddling said semiconductor material portion, wherein said planarization dielectric layer is formed on said disposable gate structure; and

removing said disposable gate structure selective to said planarization dielectric layer and to said semiconductor material portion, wherein said gate cavity is formed in a volume from which said disposable gate structure is removed.

3. The method of claim 2, wherein said removal of said disposable gate structure selective to said planarization delectric layer and said semiconductor material portion comprises a recess etch.

4. The method of claim 1, wherein said conductive material portion is formed by depositing a conductive material and removing said deposited conductive material from above a horizontal plane including a top surface of said planarization dielectric layer by a planarization process.

5. The method of claim 1, wherein said patterning of said stack of said gate dielectric layer and said work function material layer is performed by:

applying a photoresist layer over said work function material layer in said gate cavity;

lithographically patterning said photoresist layer; and

removing physically exposed portions of said work function material layer employing said patterned photoresist layer as an etch mask.

6. The method of claim 5, further comprising removing physically exposed portions of said gate dielectric layer after removal of said physically exposed portions of said work function material layer.

7. The method of claim 1, wherein said conductive material portion has a higher conductivity than said work function material layer.

8. The method of claim 1, further comprising:

forming another work function material layer on said work function material layer; and

patterning said another work function material layer, wherein a patterned portion of said another work function material layer, a patterned portion of said work function material layer, and a patterned portion of said gate dielectric layer include sidewalls that are vertically coincident among one another.

9. The method of claim 1, wherein said semiconductor material portion is a semiconductor fin.

10. The method of claim 1, wherein said substrate comprises an insulator layer and a handle substrate.

11. The method of claim 1, wherein said semiconductor material portion is doped with a p-type dopant or an n-type dopant.

12. The method of claim 1, wherein said gate dielectric layer comprises an oxide or an oxynitride of a semiconductor material.

13. The method of claim 12, wherein said gate dielectric layer is selected from silicon oxide, silicon oxynitride, an oxide of a silicon-germanium alloy, and an oxynitride of a silicon-germanium alloy.

14. The method of claim 1, wherein said gate dielectric layer comprises a high-k dielectric material.

15. The method of claim 1, wherein said gate dielectric layer is in continuous and direct contact with an entire exposed surface of surface of said semiconductor material portion.

16. The method of claim 15, wherein said work function material layer is formed directly on an outer surface of said gate dielectric layer.