Prevention of subchannel leakage current in a semiconductor device with a fin structure

• US 10,403,752 B2
• Filed: 12/22/2014
• Issued: 09/03/2019
• Est. Priority Date: 12/22/2014
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Jambunathan, Karthik, Glass, Glenn A., Mohapatra, Chandra S., Murthy, Anand S., Cea, Stephen M., Ghani, Tahir
• Primary Examiner(s): Mazumder, Didarul A
• Application Number:
  US15/525,183
• Publication Number:
  US 20170330966A1
• Time in Patent Office: 1,716 Days
• Field of Search: 257241
• CPC Class Codes: H01L 29/0607 for preventing surface leakage or controlling electric field concentration
• CPC Class Codes: H01L 29/1054 with a variation of the composition, e.g. channel with strained layer for increasing the mobility
• 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 29/66803 with a step of doping the vertical sidewall, e.g. using tilted or multi-angled implants
• CPC Class Codes: H01L 29/7831 with multiple gate structure FinFETs or MuGFETs H01L29/7855, thin film transistors H01L29/78645
• 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

An embodiment includes an apparatus comprising: a fin structure on a substrate, the fin structure including fin top and bottom portions, a channel including a majority carrier, and an epitaxial (EPI) layer; an insulation layer including insulation layer top and bottom portions adjacent the fin top and bottom portions; wherein (a) the EPI layer comprises one or more of group IV and lll-V materials, (b) the fin bottom portion includes a fin bottom portion concentration of dopants of opposite polarity to the majority carrier, (c) the fin top portion includes a fin top portion concentration of the dopants less than the fin bottom portion concentration, (d) the insulation layer bottom portion includes an insulation layer bottom portion concentration of the dopants, and (e) the insulation layer top portion includes an insulation top layer portion concentration greater than the insulation bottom portion concentration. Other embodiments are described herein.

Claims

1. An apparatus comprising:

a fin structure on a substrate, the fin structure including a fin top portion, a fin bottom portion, a channel including a majority carrier, and an epitaxial (EPI) layer; and

an insulation layer including an insulation layer top portion, adjacent the fin top portion, and an insulation layer bottom portion, adjacent the fin bottom portion;

wherein the EPI layer comprises at least one of a group IV material, a group III-V material, or combinations thereof, the fin bottom portion includes a fin bottom portion concentration of dopants of opposite polarity to the majority carrier, the fin top portion includes a fin top portion concentration of the dopants less than the fin bottom portion concentration, the insulation layer bottom portion includes an insulation layer bottom portion concentration of the dopants, and the insulation layer top portion includes an insulation top layer portion concentration greater than the insulation bottom portion concentration.

2. The apparatus of claim 1 including a well within the fin bottom portion.

3. The apparatus of claim 1 wherein the EPI layer comprises the group III-V material.

4. The apparatus of claim 3 wherein the EPI layer is included in the channel and couples to a source and a drain of a transistor.

5. The apparatus of claim 3 comprising the substrate, wherein the substrate includes Si.

6. The apparatus of claim 1 wherein the fin structure is not monolithic with the substrate.

7. The apparatus of claim 6 wherein the channel is strained.

8. The apparatus of claim 7 wherein the insulation layer extends below a bottommost edge of the fin structure.

9. The apparatus of claim 1 wherein the fin structure extends above a top-most edge of the insulation layer.

10. The apparatus of claim 1 wherein the fin structure includes a fin middle portion, between the fin top and bottom portions, including a fin middle portion concentration of dopants that is less than the fin bottom portion concentration and greater than the fin top portion concentration.

11. The apparatus of claim 1, wherein:

the fin bottom portion includes a first subportion and a second subportion below the first subportion;

the first subportion includes a first subportion concentration of the dopants; and

the second subportion includes a second subportion concentration of the dopants less than the first subportion concentration.

12. The apparatus of claim 1, wherein:

the EPI layer is included in both of the fin top and bottom portions;

the EPI layer included in the fin top portion has fewer dislocations than the EPI layer included in the bottom fin portion; and

the fin structure is included in a trench having an aspect ratio (height;

width) of at least 2;

1.

13. The apparatus of claim 1, wherein the fin bottom portion includes a first material having a first energy bandgap and the fin top portion includes a second material having a second energy bandgap that is lower than the first energy bandgap.

14. The apparatus of claim 1 comprising:

an additional fin structure on the substrate, the additional fin structure including an additional fin top portion, an additional fin bottom portion, an additional channel including an additional majority carrier opposite the majority carrier, and an additional EPI layer; and

an additional insulation layer including an additional insulation layer top portion, adjacent the additional fin top portion, and an additional insulation layer bottom portion, adjacent the additional fin bottom portion;

wherein (a) the additional EPI layer comprises at least one of a group IV material, a group III-V material, or a combination thereof, (b) the additional fin bottom portion includes an additional fin bottom portion concentration of additional dopants of opposite polarity to the additional majority carrier, (c) the additional fin top portion includes an additional fin top portion concentration of the additional dopants less than the additional fin bottom portion concentration, (d) the additional insulation layer bottom portion includes an additional insulation layer bottom portion concentration of the additional dopants, and (e) the additional insulation layer top portion includes an additional insulation top layer portion concentration greater than the additional insulation bottom portion concentration.

15. The apparatus of claim 1, wherein the fin top portion is included in an upper half of the fin structure, the fin bottom portion is included in a lower half of the fin structure, the insulation layer top portion is included in a top half of the insulation layer, and the insulation bottom portion is included in a bottom half of the insulation layer.

16. An apparatus comprising:

a fin structure on a substrate, the fin structure including a fin top portion, a fin bottom portion, a channel including a majority carrier, and an epitaxial (EPI) layer; and

an insulation layer including an insulation layer top portion that is adjacent to and directly contacting the fin top portion, and an insulation layer bottom portion that is adjacent to and directly contacting the fin bottom portion;

wherein;

the EPI layer comprises at least one of a group IV material, a group III-V material, or a combination thereof, the fin bottom portion includes a fin bottom portion concentration of dopants of opposite polarity to the majority carrier, the fin top portion includes a fin top portion concentration of the dopants less than the fin bottom portion concentration.

17. The apparatus of claim 16 including a well within the fin bottom portion and wherein the insulation layer top and bottom portions are each within 20 nm of the fin structure.

18. The apparatus of claim 16 wherein the fin structure extends above a top-most edge of the insulation layer.