FETs and methods for forming the same

• US 9,818,878 B2
• Filed: 05/11/2016
• Issued: 11/14/2017
• Est. Priority Date: 02/27/2013
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Huang, Yu-Lien, Fan, Chun-Hsiang, Lee, Tung Ying, Liu, Chi-Wen
• Primary Examiner(s): Erdem, Fazli
• Application Number:
  US15/152,357
• Publication Number:
  US 20160254384A1
• Time in Patent Office: 552 Days
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/122 Single quantum well structures single heterojunctions, couples of materials H01L29/165, H01L29/205, H01L29/225, H01L29/267
• CPC Class Codes: H01L 29/165 in different semiconductor regions , e.g. heterojunctions
• 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 29/66666 Vertical transistors H01L29/66712, H01L29/66742 take precedence
• 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 29/66977 Quantum effect devices, e.g. using quantum reflection, diffraction or interference effects, i.e. Bragg- or Aharonov-Bohm effects
• CPC Class Codes: H01L 29/7827 Vertical transistors H01L29/7802, H01L29/78642 take precedence
• CPC Class Codes: H01L 29/7853 the body having a non-rectangular crossection

Abstract

FETs and methods for forming FETs are disclosed. A structure comprises a substrate, a gate dielectric and a gate electrode. The substrate comprises a fin, and the fin comprises an epitaxial channel region. The epitaxial channel has a major surface portion of an exterior surface. The major surface portion comprising at least one lattice shift, and the at least one lattice shift comprises an inward or outward shift relative to a center of the fin. The gate dielectric is on the major surface portion of the exterior surface. The gate electrode is on the gate dielectric.

Claims

1. A structure comprising:

a substrate comprising a fin, the fin comprising an epitaxial channel region, the epitaxial channel region having a major surface portion of an exterior surface, the major surface portion comprising at least one lattice shift, wherein the at least one lattice shift comprises an inward or outward shift relative to a center of the fin;

a gate dielectric on the major surface portion of the exterior surface; and

a gate electrode on the gate dielectric.

2. The structure of claim 1, wherein the epitaxial channel region comprises a quantum well along the exterior surface.

3. The structure of claim 1, wherein the gate dielectric substantially surrounds the epitaxial channel region.

4. The structure of claim 1, wherein the substrate has a substrate major surface, the major surface portion having a deviation angle from a normal to the substrate major surface exceeding 2 degrees.

5. The structure of claim 1, wherein the major surface portion has a defined crystalline surface orientation.

6. The structure of claim 1, wherein the major surface portion comprises a plurality of lattice shifts, the lattice shifts comprising a plurality of inward shifts.

7. A structure comprising:

a substrate having a major surface;

a transistor structure on the substrate and extending in a direction normal to the major surface, the transistor structure comprising a first source/drain region, a channel region, and a second source/drain region, the channel region being on the first source/drain region in the direction normal to the major surface, the second source/drain region being on the channel region in the direction normal to the major surface, the channel region having a sidewall surface, a deviation angle of the sidewall surface from the direction normal to the major surface exceeding 2 degrees; and

a gate structure surrounding the channel region in a plane perpendicular to the direction normal to the major surface.

8. The structure of claim 7, wherein the sidewall surface has a defined crystalline surface orientation.

9. The structure of claim 8, wherein the defined crystalline surface orientation is a (991) surface, a (881) surface, a (771) surface, a (661) surface, a (551) surface, a (441) surface, a (331) surface, or a (221) surface.

10. The structure of claim 7, wherein the channel region has a circular cross section in the plane perpendicular to the direction normal to the major surface.

11. The structure of claim 7, wherein the channel region has a rectangular cross section in the plane perpendicular to the direction normal to the major surface.

12. The structure of claim 7, wherein the sidewall surface comprises a lattice shift of at least two lattice spacings.

13. The structure of claim 7, wherein the sidewall surface comprises a plurality of lattice shifts, respective distances between neighboring lattice shifts being between 2 atoms and 20 atoms along a direction perpendicular to the lattice shifts.

14. A structure comprising:

a fin on a substrate;

a first source/drain region and a second source/drain region in the fin, a portion of the fin being disposed between the first source/drain region and the second source/drain region, an upper part of the portion of the fin having a V-shaped recess;

a channel region over the V-shaped recess;

a void between the upper part of the portion of the fin and the channel region;

a gate dielectric in the void; and

a gate electrode in the void.

15. The structure of claim 14, wherein the gate dielectric and the gate electrode surround the channel region.

16. The structure of claim 14, wherein the channel region comprises a quantum well.

17. The structure of claim 14, wherein the channel region has a major surface portion of an exterior surface, the major surface portion comprising at least one lattice shift, wherein the at least one lattice shift comprises an inward or outward shift relative to a center of the fin.

18. The structure of claim 17, wherein the major surface portion comprises a plurality of lattice shifts, the lattice shifts comprising a plurality of inward shifts and a plurality of outward shifts.

19. The structure of claim 17, wherein the major surface portion comprises a plurality of lattice shifts, respective distances between neighboring lattice shifts being between 2 atoms and 20 atoms along a direction perpendicular to the lattice shifts.

20. The structure of claim 17, wherein the at least one lattice shift comprises at least two lattice spacings.