FINFET WITH SELF-ALIGNED PUNCHTHROUGH STOPPER

• US 20140061794A1
• Filed: 08/29/2012
• Published: 03/06/2014
• Est. Priority Date: 08/29/2012
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Cheng, Kangguo, Haran, Balasubramanian S., Ponoth, Shom, Standaert, Theodorus E., Yamashita, Tenko
• Granted Patent: US 8,932,918 B2
• Time in Patent Office: Days
• US Class Current: 257/347
• CPC Class Codes: H01L 29/0653 adjoining the input or output region of a field-effect device, e.g. the source or drain region
• CPC Class Codes: H01L 29/1083 with an inactive supplementary region, e.g. for preventing punch-through, improving capacity effect or leakage current
• CPC Class Codes: H01L 29/161 including two or more of the elements provided for in group H01L29/16 , e.g. alloys H01L29/1604 takes precedence
• CPC Class Codes: H01L 29/165 in different semiconductor regions , e.g. heterojunctions
• CPC Class Codes: H01L 29/66803 with a step of doping the vertical sidewall, e.g. using tilted or multi-angled implants
• CPC Class Codes: H01L 29/7848 the means being located in the source/drain region, e.g. SiGe source and drain
• CPC Class Codes: H01L 29/7849 the means being provided under the channel
• CPC Class Codes: H01L 29/7851 with the body tied to the substrate

Abstract

A finFET with self-aligned punchthrough stopper and methods of manufacture are disclosed. The method includes forming spacers on sidewalls of a gate structure and fin structures of a finFET device. The method further includes forming a punchthrough stopper on exposed sidewalls of the fin structures, below the spacers. The method further includes diffusing dopants from the punchthrough stopper into the fin structures. The method further includes forming source and drain regions adjacent to the gate structure and fin structures.

Claims

1. A method, comprising:

forming spacers on sidewalls of a gate structure and fin structures of a finFET device;

forming a punchthrough stopper on exposed sidewalls of the fin structures, below the spacers;

diffusing dopants from the punchthrough stopper into the fin structures; and

forming source and drain regions adjacent to the gate structure and fin structures.

2. The method of claim 1, wherein the forming the punchthrough stopper comprises growing epitaxial material on the exposed sidewalls of the fin structures.

3. The method of claim 2, wherein the growing comprises an in-situ doping process.

4. The method of claim 3, wherein the epitaxial material is a strain material.

5. The method of claim 3, wherein the forming the punchthrough stopper further comprises exposing the sidewalls of the fin structures by recessing an underlying shallow trench isolation region, adjacent to the fin structures.

6. The method of claim 1, wherein the diffusing the dopants comprises an annealing process following an in situ deposition process of material forming the punchthrough stopper.

7. The method of claim 1, wherein the spacers are formed by a deposition of nitride material on the sidewalls of the gate structure and the fin structures.

8. The method of claim 7, further comprising removing the spacers from the fin structures, followed by forming the source and drain regions.

9. The method of claim 8, wherein the source and drain regions are formed by an in-situ doping process, followed by an annealing process.

10. The method of claim 1, wherein the fin structures are formed from BULK material.

11. The method of claim 1, wherein the source and drain regions are formed on shallow trench isolation structures which were partially etched to expose the sidewalls of the fin structures, prior to the forming of the punchthrough stoppers.

12. The method of claim 1, wherein the gate structure is formed in a gate-first process.

13. The method of claim 1, wherein the gate structure is formed in a gate-last process.

14. A method, comprising:

forming fin structures from at least a BULK substrate;

forming a gate structure on the fin structures and the BULK substrate;

forming shallow trench isolation structures on sidewalls of the fin structures and surfaces of the BULK substrate;

forming sidewall spacers on the sidewalls of the fin structures and sidewalls of the gate structure;

recessing the shallow trench isolation structures to exposed sidewalls of the fin structures, below the sidewall spacers;

forming punchthrough stoppers on the exposed sidewalls of the fin structures and the shallow trench isolation structures;

diffusing dopants of the punchthrough stoppers into the fin structures; and

forming source and drain regions over the punchthrough stoppers.

15. The method of claim 14, wherein the forming the punchthrough stoppers comprises growing epitaxial material on the exposed sidewalls of the fin structures with an in-situ doping process.

16. The method of claim 15, wherein the epitaxial material is a strain material.

17. The method of claim 14, wherein the diffusing the dopants comprises an annealing process following an in situ deposition process of material forming the punchthrough stopper.

18. The method of claim 14, wherein the source and drain regions are formed by an in-situ doping process, followed by an annealing process.

19. The method of claim 14, wherein the fin structures are formed from BULK material and the source and drain regions are formed from a doped strain material.

20. A structure, comprising:

a set of fins;

a gate structure directly on the set of fins;

a punchthrough stopper material on sidewalls of the set of fins, wherein a dopant of the punchthrough stopper material is under the set of fins; and

source and drain material directly on the punchthrough stopper material and adjacent to the gate and set of fins.