METHOD AND STRUCTURE FOR FORMING FINFETS WITH MULTIPLE DOPING REGIONS ON A SAME CHIP

• US 20110129978A1
• Filed: 12/01/2009
• Published: 06/02/2011
• Est. Priority Date: 12/01/2009
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Cheng, Kangguo, Doris, Bruce B., Zhang, Ying
• Granted Patent: US 8,021,949 B2
• Time in Patent Office: Days
• US Class Current: 438/302
• CPC Class Codes: H01L 21/26586 characterised by the angle between the ion beam and the crystal planes or the main crystal surface
• CPC Class Codes: H01L 29/66803 with a step of doping the vertical sidewall, e.g. using tilted or multi-angled implants

Abstract

A method for fabrication of features for an integrated circuit includes patterning a first semiconductor structure on a surface of a semiconductor device, and epitaxially growing semiconductor material on opposite sides of the first semiconductor structure to form fins. A first angled ion implantation is applied to one side of the first semiconductor structure to dope a respective fin on the one side. The first semiconductor structure is selectively removed to expose the fins. Fin field effect transistors are formed using the fins.

Claims

1. A method for fabrication of features for an integrated circuit, comprising:

patterning a first semiconductor structure on a surface of a semiconductor substrate;

epitaxially growing semiconductor material on opposite sides of the first semiconductor structure to form a first fin and a second fin;

applying a first angled ion implantation to one side of the first semiconductor structure to dope the first fin on the one side without doping the second fin;

selectively removing the first semiconductor structure to expose the first fin and the second fin; and

forming fin field effect transistors using the first fin and the second fin.

2. The method as recited in claim 1, further comprising treating the first structure to permit epitaxial growth on sidewalls of the first structure.

3. The method as recited in claim 2, wherein the first semiconductor structure includes silicon and treating the first semiconductor structure includes forming porous silicon by doping and anodizing.

4. The method as recited in claim 3, wherein epitaxially growing semiconductor material includes epitaxially growing silicon on the porous silicon of the first semiconductor structure.

5. The method as recited in claim 1, further comprising applying a second angled ion implantation to an opposite side of the first semiconductor structure to dope the second without doping the first fin.

6. The method as recited in claim 5, wherein applying the first angled ion implantation includes doping the one side with a first polarity dopant and applying the second angled ion implantation includes doping the opposite side with a second polarity dopant.

7. The method as recited in claim 5, wherein applying the first angled ion implantation includes doping the one side with a first dopant density and applying the second angled ion implantation includes doping the opposite side with a second dopant density.

8. The method as recited in claim 1, wherein epitaxially growing semiconductor material includes introducing dopants during epitaxial growth of the semiconductor material.

9. The method as recited in claim 1, wherein epitaxially growing semiconductor material includes epitaxially growing the semiconductor material such that a width of the semiconductor material includes a size less than a minimum feature size achievable by a lithographic method.

10. The method as recited in claim 1, wherein the first semiconductor structure includes a material which permits direct epitaxial growth.

11. The method as recited in claim 1, wherein the first semiconductor structure includes silicon germanium.

12. A method for fabrication of features for an integrated circuit, comprising:

patterning mandrels on a surface of a semiconductor substrate;

forming spacers about a periphery of the mandrels;

applying a first angled ion implantation to introduce a first doping such that the spacers and mandrels form a blocking mask to direct the first doping into an underlying semiconductor layer on one side of the blocking mask;

applying a second angled ion implantation in an opposite direction to the first angled ion implantation to introduce a second doping such that the blocking mask directs the second doping into the underlying semiconductor layer on an opposite side of the blocking mask;

selectively removing the mandrels relative to the spacers;

patterning the underlying semiconductor layer using the spacers as an etch mask to form fins with the first doping and fins with second doping;

annealing the fins with the first doping and fins with second doping; and

forming fin field effect transistors using the fins.

13. The method as recited in claim 12, wherein the first doping includes a first polarity dopant and the second doping includes a second polarity dopant.

14. The method as recited in claim 12, wherein the first doping includes a first dopant density and the second doping includes a second dopant density.

15. The method as recited in claim 12, wherein forming spacers includes forming spacers having a feature size less than a minimum feature size achievable by a lithographic method.

16. The method as recited in claim 12, wherein the fins have a feature size less than a minimum feature size achievable by a lithographic method.