Ultra-thin, high quality strained silicon-on-insulator formed by elastic strain transfer
View Patent ↗A method of forming a semiconductor structure comprising a first strained semiconductor layer over an insulating layer is provided in which the first strained semiconductor layer is relatively thin (less than about 500 Å) and has a low defect density (stacking faults and threading defects). The method of the present invention begins with forming a stress-providing layer, such a SiGe alloy layer over a structure comprising a first semiconductor layer that is located atop an insulating layer. The stress-providing layer and the first semiconductor layer are then patterned into at least one island and thereafter the structure containing the at least one island is heated to a temperature that causes strain transfer from the stress-providing layer to the first semiconductor layer. After strain transfer, the stress-providing layer is removed from the structure to form a first strained semiconductor island layer directly atop said insulating layer.
1. A semiconductor structure comprising:
at least a first strained semiconductor island layer located atop an insulating layer, said first strained semiconductor island layer having a threading defect (TD) density of about 10 5 defects/cm 2 or less and a stacking fault density of about 1000 defects/cm 2 or less, said first strained semiconductor island layer having a thickness of less than about 500 Å.
2. The semiconductor structure of claim 1 wherein said first strained semiconductor island layer comprises Si, SiC, SiGe, SiGeC, Ge, GaAs, InAs, InP or other III/V and II/VI compound semiconductors.
3. The semiconductor structure of claim 1 wherein said insulating layer is a buried insulating layer of a preformed silicon-on-insulator substrate.
4. The semiconductor structure of claim 1 wherein said first strained semiconductor island layer has a tensile stress.
5. The semiconductor structure of claim 1 said first strained semiconductor island layer has a compressive stress.
6. The semiconductor structure of claim 1 wherein said insulating layer is doped with a dopant species.
7. The semiconductor structure of claim 1 wherein said first strained semiconductor island layer comprises Si that is enriched in one of its isotopes.
8. The semiconductor structure of claim 1 further comprises at least one other strained semiconductor island layer on said insulating layer, said at least one other strained semiconductor island layer having a different strain value than said first strained semiconductor island layer.
9. The semiconductor structure of claim 8 wherein said first strained semiconductor island layer has a tensile stress and said at least one other strained semiconductor island layer has a compressive stress.
10. The semiconductor structure of claim 8 wherein said first strained semiconductor island layer has a compressive stress and said at least one other strained semiconductor island layer has a tensile stress.
11. The semiconductor structure of claim 10 wherein said dopant species comprises B.