Hybrid substrate technology for high-mobility planar and multiple-gate MOSFETs
View Patent ↗A hybrid substrate having a high-mobility surface for use with planar and/or multiple-gate metal oxide semiconductor field effect transistors (MOSFETs) is provided. The hybrid substrate has a first surface portion that is optimal for n-type devices, and a second surface portion that is optimal for p-type devices. Due to proper surface and wafer flat orientations in each semiconductor layers of the hybrid substrate, all gates of the devices are oriented in the same direction and all channels are located on the high mobility surface. The present invention also provides for a method of fabricating the hybrid substrate as well as a method of integrating at least one planar or multiple-gate MOSFET thereon.
1. A hybrid substrate comprising:
an upper surface comprising a second semiconductor layer and an epitaxial semiconductor layer, wherein said second semiconductor layer has a second crystallographic orientation and the epitaxial semiconductor layer has a first crystallographic orientation that differs from the second crystallographic orientation, said first and second crystallographic orientations provide optimal carrier mobility for a specific semiconductor device;
a liner or spacer separating at least said second semiconductor layer and said epitaxial semiconductor layer;
an insulating layer located beneath said second semiconductor layer; and
a first semiconductor layer located beneath said insulating layer and said epitaxial semiconductor layer, wherein said first semiconductor layer is in direct contact with a lower portion of the epitaxial semiconductor layer, has a crystallographic orientation that is the same as the epitaxial semiconductor layer, and said first semiconductor layer and said second semiconductor layer each contain a wafer flat that is aligned to each other.
2. The hybrid substrate of claim 1 wherein said first semiconductor layer and said second semiconductor layer are comprised of Si, SiC, SiGe, SiGeC, Ge, Ge alloys, GaAs, InAs, InP, a silicon-on-insulator (SOI) layer or other III/V and II/VI compound semiconductors.
3. The hybrid substrate of claim 2 wherein said first semiconductor layer and said second semiconductor layer are comprised of Si.
4. The hybrid substrate of claim 1 wherein said first semiconductor layer is comprised of Si and said first crystallographic orientation is (110) with said wafer flat in the <110> direction and said second semiconductor layer comprises Si and said second crystallographic orientation is (100) with said wafer flat in the <100> direction.
5. The hybrid substrate of claim 1 wherein said first semiconductor layer is comprised of Si and said first crystallographic orientation is (100) with said wafer flat in the <100> direction and said second semiconductor layer comprises Si and said second crystallographic orientation is (110) with said wafer flat in the <110> direction.
6. The hybrid substrate of claim 1 wherein said epitaxial semiconductor layer comprises a Si-containing semiconductor.
7. The hybrid substrate of claim 6 wherein said Si-containing semiconductor comprises Si, strained Si, SiC, SiGeC or combinations thereof.
8. The hybrid substrate of claim 1 wherein said epitaxial semiconductor layer comprises Si with a (100) crystallographic orientation.
9. The hybrid substrate of claim 1 wherein said epitaxial semiconductor layer comprises Si with a (110) crystallographic orientation.
10. The hybrid substrate of claim 1 wherein said liner or spacer comprises an oxide, nitride, oxynitride or any combination thereof.
11. The hybrid substrate of claim 1 wherein said insulating layer comprises an oxide, nitride, oxynitride or combination thereof.
12. The hybrid substrate of claim 1 further comprises a buried oxide region within at least one of said second semiconductor layer or said epitaxial semiconductor layer.
13. The hybrid substrate of claim 1 wherein said upper surface comprises at least two device regions.
14. The hybrid substrate of claim 1 wherein said upper surface comprises a (100) crystallographic orientation and a (110) crystallographic orientation.
15. The hybrid substrate of claim 14 wherein said upper surface of said (100) crystallographic orientation comprises a n-type planar or multiple-gate MOSFET device, and said surface of said (110) crystallographic orientation comprises a p-type planar or multiple-gate MOSFET device.
16. A high-mobility structure comprising:
a hybrid substrate containing an upper surface comprising a second semiconductor layer and an epitaxial semiconductor layer, wherein said second semiconductor layer has a second crystallographic orientation and the epitaxial semiconductor layer has a first crystallographic orientation that differs from the second crystallographic orientation, said first and second crystallographic orientations provide optimal carrier mobility for a specific semiconductor device; a liner or spacer separating at least said second semiconductor layer and said epitaxial semiconductor layer; an insulating layer located beneath said second semiconductor layer; a first semiconductor layer located beneath said insulating layer and said epitaxial semiconductor layer, wherein said first semiconductor layer is in direct contact with a lower portion of the epitaxial semiconductor layer, and has a crystallographic orientation that is the same as the epitaxial semiconductor layer; and
at least one planar or multiple-gate MOSFET device present on both said second semiconductor layer and said epitaxial semiconductor layer, wherein said devices have gates that are oriented in the same direction and are present on a surface that is optimal for said MOSFET device.
17. The structure of claim 16 wherein said first semiconductor layer and said second semiconductor layer are comprised of Si, SiC, SiGe, SiGeC, Ge, Ge alloys, GaAs, InAs, InP, a silicon-on-insulator (SOI) layer or other III/v and II/VI compound semiconductors.
18. The structure of claim 17 wherein said first semiconductor layer and said second semiconductor layer are comprised of Si.
19. The structure of claim 16 wherein said first semiconductor layer is comprised of Si and said first crystallographic orientation is (110) with said wafer flat in the <110> direction and said second semiconductor layer comprises Si and a second crystallographic orientation is (100) with a wafer flat in the <100> direction.
20. The structure of claim 16 wherein said first semiconductor layer is comprised of Si and said first crystallographic orientation is (100) with a wafer flat in the <100> direction and said second semiconductor layer comprises Si and said second crystallographic orientation is (110) with a wafer flat in the <110> direction.
21. The structure of claim 16 wherein said epitaxial semiconductor layer comprises a Si-containing semiconductor.
22. The structure of claim 21 wherein said Si-containing semiconductor comprises Si, strained Si, SiC, SiGeC or combinations thereof.
23. The structure of claim 16 wherein said epitaxial semiconductor layer comprises Si with a (100) crystallographic orientation.
24. The structure of claim 16 wherein said epitaxial semiconductor layer comprises Si with a (110) crystallographic orientation.
25. The structure of claim 16 wherein said liner or spacer comprises an oxide, nitride, oxynitride or any combination thereof.
26. The structure of claim 16 wherein said insulating layer comprises an oxide, nitride, oxynitride or combination thereof.
27. The structure of claim 16 further comprises a buried oxide region within at least one of said second semiconductor layer or said epitaxial semiconductor layer.
28. The structure of claim 16 wherein said upper surface comprises at least two device regions.
29. The structure of claim 16 wherein said upper surface comprises a (100) crystallographic orientation and a (110) crystallographic orientation.
30. The structure of claim 29 wherein said upper surface of said (100) crystallographic orientation comprises a n-type planar or multiple-gate MOSFET device, and said surface of said (110) crystallographic orientation comprises a p-type planar or multiple-gate MOSFET device.