Process for the transfer of a thin layer formed in a substrate with vacancy clusters
View Patent ↗Methods for forming semiconductor structures comprising a layer transferred from a donor substrate are provided in which the resulting structure has improved quality with respect to defects and resulting structures therefrom. For example, a semiconductor-on-insulator (SeOI) structure can be formed by a method comprising:—providing a donor substrate having a first density of vacancy clusters;—providing an insulating layer; —transferring a thin layer from the donor substrate to a support substrate with the insulating layer thereon;—curing the transferred thin layer to reduce the first density of vacancy clusters to a second density; and being characterized in that the step of providing an insulating layer comprises providing an oxygen barrier layer to be in contact with the transferred thin layer, the oxygen barrier layer limiting diffusion of oxygen toward the thin layer during the curing.
1. A method for forming a semiconductor-on-insulator structure comprising:
transferring a thin layer from a donor substrate to a support substrate;
providing an oxygen barrier layer between the thin layer of the donor substrate and the support substrate;
curing the transferred thin layer to reduce a density of vacancy clusters in the transferred thin layer from a first density of vacancy clusters to a second density of vacancy clusters; and
limiting diffusion of oxygen into the thin layer from an insulating layer on the support substrate using the oxygen barrier layer during the curing.
2. A method according to claim 1 , further comprising:
forming the insulating layer to comprise the oxygen barrier layer; and
providing the insulating layer on the support substrate before transferring the thin layer from the donor substrate to the support substrate.
3. A method according to claim 1 , further comprising:
forming the insulating layer to comprise a buried layer; and
providing the buried layer between the support substrate and the oxygen barrier layer.
4. A method according to claim 3 , further comprising providing the buried layer on a surface of the support substrate.
5. A method according to claim 3 , further comprising thermally oxidizing a surface of the support substrate to form the buried layer.
6. A method according to claim 3 , further comprising depositing the buried layer on a surface of the support substrate.
7. A method according to claim 3 , further comprising:
providing the buried layer on the support substrate;
providing the oxygen barrier layer on the buried layer; and
transferring the thin layer from the donor substrate onto the oxygen barrier layer after providing the oxygen barrier layer on the buried layer.
8. A method according to claim 3 , further comprising providing the oxygen barrier layer on the donor substrate prior to transferring the thin layer from the donor substrate to the support substrate.
9. A method according to claim 8 , further comprising transferring the oxygen barrier layer from the donor substrate to the support substrate together with the thin layer.
10. A method according to claim 9 , further comprising providing the buried layer on the support substrate prior to transferring the thin layer from the donor substrate to the support substrate together with the thin layer.
11. A method according to claim 8 , further comprising providing the buried layer on the oxygen barrier layer prior to transferring the thin layer from the donor substrate to the support substrate.
12. A method according to claim 11 , further comprising transferring the oxygen barrier layer and the buried layer from the donor substrate to the support substrate together with the thin layer.
13. A method according to claim 1 , further comprising forming the oxygen barrier layer by depositing a silicon nitride layer.
14. A method according to claim 13 , further comprising employing a Plasma Enhanced Chemical Vapor Deposition (PECVD) process to deposit the silicon nitride layer.
15. A method according to claim 1 , wherein curing the transferred thin layer comprises thermally annealing the thin layer after transferring the thin layer from the donor substrate to the support substrate.
16. A method according to claim 15 , further comprising providing the thin layer in a non-oxidizing atmosphere while thermally annealing the thin layer.
17. A method according to claim 16 , further comprising providing the thin layer in an atmosphere of at least one of pure hydrogen, pure argon and a mixture of hydrogen and argon while thermally annealing the thin layer.
18. A method according to claim 17 , wherein thermally annealing the thin layer comprises rapid thermal processing (RTP).
19. A method according to claim 16 , wherein thermally annealing comprises smoothing annealing performed under an atmosphere comprising hydrogen and hydrochloric acid.
20. A method according to claim 1 , further comprising:
providing a zone of weakness in the donor substrate to define the thin layer;
combining the donor substrate, the insulating layer and support substrate together; and
detaching the thin layer from the donor substrate at the zone of weakness.
21. A method according to claim 1 , further comprising:
pulling an ingot at a rate of at least 0.75 mm/min.; and
cutting the ingot to form the donor substrate.
22. A method according to claim 21 , further comprising:
forming the donor substrate to have a density of vacancies larger than 0.14 μm that is less than 0.01/cm 2 ;
wherein curing the transferred thin layer comprises reducing a density of vacancies larger than 0.14 μm in the transferred layer to a density of 0.075/cm 2 or less.
23. A method according to claim 21 , further comprising:
forming the donor substrate to have a density of vacancies larger than 0.2 μm that is greater than 1.5/cm 2 ;
wherein curing the transferred thin layer comprises reducing a density of vacancies larger than 0.2 μm in the transferred layer to a density of 0.075/cm 2 or less.
24. A method according to claim 1 , further comprising detaching an additional thin layer from the donor substrate for forming circuitry therein.