US6774015B1
Expired / Lapsed
US
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Strained silicon-on-insulator (SSOI) and method to form the same
Assignee: International Business Machines Corp
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Filing: 2002-12-19
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Granted: 2004-08-10
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Expires: 2022-12-19
Abstract
Abstract A method for fabricating a strained Si layer on insulator, a structure of the strained Si layer on insulator, and electronic systems comprising such layers are disclosed. The method comprises the steps of forming epitaxially a relaxed SiGe layer on top of a Si layer on insulator; transforming the crystalline Si layer and the lower portion of the crystalline relaxed SiGe layer into an amorphous material state by ion implantation; and re-crystallizing the amorphous material from the crystalline top portion of the SiGe layer. The larger lattice constant of the SiGe seed layer forces a tensile strain in the Si layer.
Inventors
- 👤 Guy Moshe Cohen
- 👤 Silke Hildegard Christiansen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:05
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/20; H10P90/00; H10P90/19; H10P90/1904; H10P90/1906; H10P90/1908; H10D; H10D86/00; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2905; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P14/38; H10P14/3802; H10P14/3822; H10W; H10W10/00; H10W10/10; H10W10/181
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
185 words
A method for tensilely straining a Si layer on an insulator, comprising the steps of: taking a silicon-on-insulator wafer, said wafer comprising a buried insulator layer sandwiched between a Si substrate and a monocrystalline Si layer, said Si layer having a first lattice constant; forming an epitaxial relaxed SiGe layer on top of said Si layer; converting said Si layer and a bottom portion of said SiGe layer into an amorphous state by an ion implantation, wherein said bottom portion of said SiGe layer is sharing a first interface with said Si layer; and re-crystallizing said bottom portion of said SiGe layer and said Si layer by solid phase epitaxy, said solid phase epitaxy seeding from a second interface between a crystalline top portion of said SiGe layer and said amorphous bottom portion of said SiGe layer, wherein at said second interface said top portion of said SiGe layer having a second lattice constant, said second lattice constant being larger than said first lattice constant, whereby upon re-crystallization said Si layer is forced to comply with said second lattice constant and acquires a tensile strain.
Claim 2
Independent Claim
185 words
A method for tensilely straining a Si layer on an insulator, comprising the steps of: taking a silicon-on-insulator wafer, said wafer comprising a buried insulator layer sandwiched between a Si substrate and a monocrystalline Si layer, said Si layer having a first lattice constant; forming an epitaxial relaxed SiGe layer on top of said Si layer; converting said Si layer and a bottom portion of said SiGe layer into an amorphous state by an ion implantation, wherein said bottom portion of said SiGe layer is sharing a first interface with said Si layer; and re-crystallizing said bottom portion of said SiGe layer and said Si layer by solid phase epitaxy, said solid phase epitaxy seeding from a second interface between a crystalline top portion of said SiGe layer and said amorphous bottom portion of said SiGe layer, wherein at said second interface said top portion of said SiGe layer having a second lattice constant, said second lattice constant being larger than said first lattice constant, whereby upon re-crystallization said Si layer is forced to comply with said second lattice constant and acquires a tensile strain.
Claim 3
Dependent Claim
22 words
The method of claim 1 , wherein said Si layer is chosen to be between about 1 nm and 100 nm thick.
Claim 4
Dependent Claim
22 words
The method of claim 2 , wherein said Si layer is chosen to be between about 2 nm and 50 nm thick.
Claim 5
Dependent Claim
19 words
The method of claim 1 , wherein in said ion implantation an implanted species is chosen to be Si.
Claim 6
Dependent Claim
19 words
The method of claim 1 , wherein in said ion implantation an implanted species is chosen to be Ge.
Claim 7
Dependent Claim
23 words
The method of claim 1 , wherein said relaxed SiGe layer is formed to a thickness between about 20 nm and 3000 nm.
Claim 8
Dependent Claim
18 words
The method of claim 1 , wherein said buried insulator layer is chosen to be SiO 2 .
Claim 9
Independent Claim
206 words
A method for fabricating a tensilely strained Si layer on an insulator, comprising the steps of: taking a silicon-on-insulator wafer, said wafer comprising a buried insulator layer sandwiched between a Si substrate and a monocrystalline Si layer, said Si layer having a first lattice constant; forming an epitaxial relaxed SiGe layer on top of said Si layer; converting said Si layer and a bottom portion of said SiGe layer into an amorphous state by an ion implantation, wherein said bottom portion of said SiGe layer is sharing a first interface with said Si layer; re-crystallizing said bottom portion of said SiGe layer and said Si layer by solid phase epitaxy, said solid phase epitaxy seeding from a second interface between a crystalline top portion of said SiGe layer and said amorphous bottom portion of said SiGe layer, wherein at said second interface said top portion of said SiGe layer having a second lattice constant, said second lattice constant being larger than said first lattice constant, whereby upon re-crystallization said Si layer is forced to comply with said second lattice constant and acquires a tensile strain; and removing said SiGe layer, whereby said silicon-on-insulator wafer has been transformed into a wafer comprising said tensilely strained Si layer.
Claim 10
Independent Claim
206 words
A method for fabricating a tensilely strained Si layer on an insulator, comprising the steps of: taking a silicon-on-insulator wafer, said wafer comprising a buried insulator layer sandwiched between a Si substrate and a monocrystalline Si layer, said Si layer having a first lattice constant; forming an epitaxial relaxed SiGe layer on top of said Si layer; converting said Si layer and a bottom portion of said SiGe layer into an amorphous state by an ion implantation, wherein said bottom portion of said SiGe layer is sharing a first interface with said Si layer; re-crystallizing said bottom portion of said SiGe layer and said Si layer by solid phase epitaxy, said solid phase epitaxy seeding from a second interface between a crystalline top portion of said SiGe layer and said amorphous bottom portion of said SiGe layer, wherein at said second interface said top portion of said SiGe layer having a second lattice constant, said second lattice constant being larger than said first lattice constant, whereby upon re-crystallization said Si layer is forced to comply with said second lattice constant and acquires a tensile strain; and removing said SiGe layer, whereby said silicon-on-insulator wafer has been transformed into a wafer comprising said tensilely strained Si layer.
Claim 11
Dependent Claim
22 words
The method of claim 8 , wherein said Si layer is chosen to be between about 1 nm and 100 nm thick.
Claim 12
Dependent Claim
22 words
The method of claim 9 , wherein said Si layer is chosen to be between about 2 nm and 50 nm thick.
Claim 13
Dependent Claim
19 words
The method of claim 8 , wherein in said ion implantation an implanted species is chosen to be Si.
Claim 14
Dependent Claim
19 words
The method of claim 8 , wherein in said ion implantation an implanted species is chosen to be Ge.
Claim 15
Dependent Claim
18 words
The method of claim 8 , wherein said buried insulator layer is chosen to be SiO 2 .
Claim 16
Dependent Claim
18 words
The method of claim 8 , wherein said relaxed SiGe layer is formed by a step grading process.
Claim 17
Dependent Claim
19 words
The method of claim 8 , wherein said relaxed SiGe layer is formed by an implant and anneal process.
Claim 18
Dependent Claim
23 words
The method of claim 8 , wherein said relaxed SiGe layer is formed to a thickness between about 20 nm and 3000 nm.
Claim 19
Dependent Claim
71 words
The method of claim 8 , further comprising the steps of: repeating at least once the converting and the re-crystallizing steps in a manner that with each repetition at said second interface said second lattice constant is increasing with each repetition, whereby said tensile strain in said Si layer also increases with each repetition; and terminating said repeating when said tensile strain in said Si layer has reached a predetermined value.
Claim 20
Independent Claim
269 words
A method for fabricating a tensilely strained Si layer on an insulator, comprising the steps of: taking a silicon-on-insulator wafer, said wafer comprising a buried SiO 2 layer sandwiched between a Si substrate and a monocrystalline Si layer, said Si layer having a first lattice constant; forming an epitaxial relaxed SiGe layer on top of said Si layer; converting said Si layer and a bottom portion of said SiGe layer into an amorphous state by an ion implantation, wherein said bottom portion of said SiGe layer is sharing a first interface with said Si layer; re-crystallizing said bottom portion of said SiGe layer and said Si layer by solid phase epitaxy, said solid phase epitaxy seeding from a second interface between a crystalline top portion of said SiGe layer and said amorphous bottom portion of said SiGe layer, wherein at said second interface said top portion of said SiGe layer having a larger lattice constant than said first lattice constant, whereby upon re-crystallization said Si layer is forced to comply with said larger lattice constant and acquires a tensile strain; removing said SiGe layer, whereby a silicon-on-insulator wafer has been provided anew, with said Si layer tensilely strained by having said first lattice constant increased; repeating at least once the growing, converting, re-crystallizing and removing steps with said provided anew silicon-on-insulator wafer, in a manner that at said second interface said second lattice constant is increasing with each repetition, whereby said tensile strain in said Si layer also increases with each repetition; and terminating said repeating when said tensile strain in said Si layer has reached a predetermined value.
Claim 21
Independent Claim
269 words
A method for fabricating a tensilely strained Si layer on an insulator, comprising the steps of: taking a silicon-on-insulator wafer, said wafer comprising a buried SiO 2 layer sandwiched between a Si substrate and a monocrystalline Si layer, said Si layer having a first lattice constant; forming an epitaxial relaxed SiGe layer on top of said Si layer; converting said Si layer and a bottom portion of said SiGe layer into an amorphous state by an ion implantation, wherein said bottom portion of said SiGe layer is sharing a first interface with said Si layer; re-crystallizing said bottom portion of said SiGe layer and said Si layer by solid phase epitaxy, said solid phase epitaxy seeding from a second interface between a crystalline top portion of said SiGe layer and said amorphous bottom portion of said SiGe layer, wherein at said second interface said top portion of said SiGe layer having a larger lattice constant than said first lattice constant, whereby upon re-crystallization said Si layer is forced to comply with said larger lattice constant and acquires a tensile strain; removing said SiGe layer, whereby a silicon-on-insulator wafer has been provided anew, with said Si layer tensilely strained by having said first lattice constant increased; repeating at least once the growing, converting, re-crystallizing and removing steps with said provided anew silicon-on-insulator wafer, in a manner that at said second interface said second lattice constant is increasing with each repetition, whereby said tensile strain in said Si layer also increases with each repetition; and terminating said repeating when said tensile strain in said Si layer has reached a predetermined value.
Claim 22
Independent Claim
192 words
A method for modifying a strain state in a first crystalline layer on a support platform, comprising the steps of: taking said first crystalline layer on said support platform, said first crystalline layer having a first lattice constant; forming an epitaxial relaxed second crystalline layer on top of said first crystalline layer; converting said first crystalline layer and a bottom portion of said second crystalline layer into an amorphous state by an ion implantation, wherein said bottom portion of said second crystalline layer is sharing a first interface with said first crystalline layer; and re-crystallizing said bottom portion of said second crystalline layer and said first crystalline layer by solid phase epitaxy, said solid phase epitaxy seeding from a second interface between a crystalline top portion of said second crystalline layer and said amorphous bottom portion of said second crystalline layer, wherein at said second interface said top portion of said second crystalline layer having a second lattice constant, said second lattice constant differing from said first lattice constant, whereby upon re-crystallization said first crystalline layer by being forced to comply with said second lattice constant has its said strain state modified.
Claim 23
Independent Claim
192 words
A method for modifying a strain state in a first crystalline layer on a support platform, comprising the steps of: taking said first crystalline layer on said support platform, said first crystalline layer having a first lattice constant; forming an epitaxial relaxed second crystalline layer on top of said first crystalline layer; converting said first crystalline layer and a bottom portion of said second crystalline layer into an amorphous state by an ion implantation, wherein said bottom portion of said second crystalline layer is sharing a first interface with said first crystalline layer; and re-crystallizing said bottom portion of said second crystalline layer and said first crystalline layer by solid phase epitaxy, said solid phase epitaxy seeding from a second interface between a crystalline top portion of said second crystalline layer and said amorphous bottom portion of said second crystalline layer, wherein at said second interface said top portion of said second crystalline layer having a second lattice constant, said second lattice constant differing from said first lattice constant, whereby upon re-crystallization said first crystalline layer by being forced to comply with said second lattice constant has its said strain state modified.
Claim 24
Dependent Claim
30 words
The method for modifying a strain state of claim 19 , further comprising the step of: removing said second crystalline layer from said first crystalline layer, following said re-crystallizing step.
Claim 25
Dependent Claim
30 words
The method for modifying a strain state of claim 19 , wherein said support platform is comprising an amorphous material, wherein said amorphous material interfacing with said first crystalline layer.
References Cited (Backward Citations)
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