Cross-coupling of gate conductor line and active region in semiconductor devices

• US 8,853,700 B2
• Filed: 08/10/2011
• Issued: 10/07/2014
• Est. Priority Date: 08/10/2011
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Sardesai, Viraj Y., Wong, Robert C.
• Primary Examiner(s): Tran, Tan N
• Assistant Examiner(s): Wilson, Scott R
• Application Number:
  US13/207,102
• Publication Number:
  US 20130037864A1
• Time in Patent Office: 1,154 Days
• Field of Search: None
• US Class Current: 257/66
• CPC Class Codes: H01L 21/76895 Local interconnects; Local pads, as exemplified by patent document EP0896365
• CPC Class Codes: H01L 27/0211 adapted for requirements of temperature
• CPC Class Codes: H01L 27/092 complementary MIS field-effect transistors
• 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 29/66545 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: H10B 10/12 comprising a MOSFET load element
• CPC Class Codes: Y10S 257/903 FET configuration adapted for use as static memory cell
• CPC Class Codes: Y10S 257/904 with passive components,, e.g. polysilicon resistors

Abstract

Cross-coupling between a gate conductor and an active region of a semiconductor substrate is provided by forming a gate dielectric layer on the semiconductor substrate and lithographically patterning the gate dielectric layer to form opening therein over a portion of the active region at which electrical contact with the gate conductor is desired. After implanting electrical dopants, a gate conductor layer is deposited and patterned. A remaining portion of the gate conductor layer includes an integral conductor structure, which includes a first portion overlying a gate dielectric over an active region and a second portion contacting the semiconductor material of the same active region or a different active region. The gate dielectric layer can be deposited within gate cavities in planarization dielectric material layer in a replacement gate scheme, or can be deposited on planar surfaces of active regions and/or shallow trench isolation structures in a gate first processing scheme.

Claims

1. A semiconductor structure comprising:

a gate dielectric contacting a portion of an active region comprising a semiconductor material and located in a substrate;

a gate conductor of unitary construction comprising a first gate conductor portion that overlies said gate dielectric and a second gate conductor portion that contacts a semiconductor surface, wherein said semiconductor surface is selected from a surface of said active region and a surface of another active region located in said substrate; and

a gate spacer laterally contacting, and surrounding, said gate conductor, wherein an edge of a bottommost surface of said gate conductor coincides with an inner periphery of a bottom surface of said gate spacer and another edge of said bottommost surface of said gate conductor coincides with an edge of a bottom surface of said gate dielectric.

2. The semiconductor structure of claim 1, wherein said gate dielectric includes a horizontal portion and a vertical portion, said horizontal portion having a bottom surface that contacts said portion of said active region, and said vertical portion extends above a top surface of said horizontal portion.

3. The semiconductor structure of claim 2, wherein an outer sidewall of said vertical portion and a sidewall of said gate conductor are within a same vertical plane.

4. The semiconductor structure of claim 1, wherein said semiconductor surface is said surface of said another active region, and said gate dielectric contacts a top surface of a shallow trench isolation structure that laterally contacts said active region and said another active region.

5. The semiconductor structure of claim 1, wherein said gate dielectric comprises a dielectric material including at least one metal and oxygen, and has a dielectric constant greater than 8.0.

6. The semiconductor structure of claim 5, wherein said gate conductor comprises a metallic material that contacts said gate dielectric

7. The semiconductor structure of claim 1, wherein said gate dielectric includes a dielectric material that is a compound of said semiconductor material and at least one of oxygen and nitrogen.

8. The semiconductor structure of claim 1, wherein said semiconductor surface is said surface of said another active region, and said gate conductor contacts a top surface of a shallow trench isolation structure that laterally contacts said active region and said another active region.

9. The semiconductor structure of claim 1, wherein said semiconductor structure comprises a static random access memory (SRAM) cell, said second gate conductor portion contacts said surface of said another active region, said active region is a drain region of an n-type field effect transistor in said SRAM cell, and said another active region is a drain region of a p-type field effect transistor in said SRAM cell.

10. The semiconductor structure of claim 9, further comprising:

another gate dielectric contacting a portion of a drain of another n-type field effect transistor in said SRAM cell; and

another gate conductor of unitary construction overlying said another gate dielectric and contacting a drain of another p-type field effect transistor in said SRAM cell.

11. The semiconductor structure of claim 1, wherein said edge of said bottommost surface of said gate conductor coincides with a bottom edge of a vertical interface between said gate spacer and said gate electrode.

12. The semiconductor structure of claim 1, wherein said inner periphery of a bottom surface of said gate spacer is located below a horizontal plane including a top surface of said gate dielectric.

13. The semiconductor structure of claim 1, further comprising a shallow trench isolation structure located in said substrate, wherein an edge of said gate dielectric overlies, and is adjoined to, a topmost surface of said shallow trench isolation structure.

14. The semiconductor structure of claim 13, wherein a bottom edge of a vertical interface between said gate conductor and gate spacer is on said surface of said active region.

15. The semiconductor structure of claim 14, wherein said bottom edge of said vertical interface contiguously extends at least from one sidewall of said active region to another sidewall of said active region.

16. The semiconductor structure of claim 13, wherein a top edge of an interface between said active region and said shallow trench isolation structure is on a bottommost surface of said gate conductor.

17. The semiconductor structure of claim 1, wherein a portion of said gate conductor in contact with said semiconductor surface has a first width, another portion of said gate conductor that is not in contact with said semiconductor surface has a second width, and said first width is greater than said second width.

18. The semiconductor structure of claim 17, wherein said first width is greater than said second width by twice a thickness of a vertical portion of said gate dielectric.

19. The semiconductor structure of claim 1, wherein said semiconductor surface is within a same horizontal plane as a bottom surface of said gate dielectric.