Method for fabricating a semiconductor on insulator type substrate

1. A method for fabricating a semiconductor on insulator type substrate, which comprises:

forming an epitaxial layer of semiconducting material on a face of donor substrate that contains oxygen precipitates having a density of less than 10 10 /cm 3 or a mean size of less than 500 nm,

forming an oxide layer on either the donor substrate or a receiver substrate,

implanting atomic species in the donor substrate to form a weakened zone in the epitaxial layer,

bonding the donor and receiver substrates together to provide the oxide layer present at the bonding interface between the substrates,

fracturing the donor substrate in the weakened zone to transfer a layer of the donor substrate to the receiver substrate with the transferred layer including at least part of the epitaxial layer, and

recycling the remainder of the donor substrate as a receiver substrate for fabrication of a second semiconductor on insulator type substrate.

2. The method according to claim 1 , wherein the remainder of the donor substrate which is recycled as the receiver substrate includes at least part of the epitaxial layer.

3. The method according to claim 2 , wherein the epitaxial layer on the recycled receiver substrate has a thickness that is greater than 100 nm.

4. The method according to claim 1 , which further comprises conducting a thermal treatment of the donor substrate before the forming of the eptiaxial layer thereon.

5. The method according to claim 1 , wherein the epitaxial layer is a layer of silicon having a thickness of between 0.5 and 8 μm.

6. The method according to claim 1 , wherein the donor substrate comprises 2 to 40 ppm of diluted oxygen.

7. The method according to claim 1 , wherein the donor substrate comprises nitrogen atoms.

8. The method according to claim 7 , wherein the nitrogen atoms have a density that is less than 10 15 atoms/cm 3 .

9. The method according to claim 1 , wherein the donor substrate comprises a polycrystalline silicon layer or an oxide layer on a rear face opposite the face that includes the epitaxial layer.

10. The method according to claim 1 , wherein the recycling of the remainder of the donor substrate includes polishing of two faces of the remainder or of a side edge thereof.

11. The method according to claim 1 , wherein the recycling of the remainder of the donor substrate includes chemical mechanical polishing of a face of the remainder that includes the fractured weakened zone.

12. The method according to claim 1 , wherein the epitaxied layer comprises silicon, germanium or SiGe.

13. In a method for recycling a donor substrate after transfer of a layer to a receiver substrate to form a first semiconductor on insulator type substrate, with the recycled donor substrate being used as receiver substrate for forming a second semiconductor on insulator type substrate, the improvement which comprises:

selecting a donor substrate that contains oxygen precipitates having a density of less than 10 10 /cm 3 or a mean size of less than 500 nm,

providing an epitaxial layer of semiconducting material on the donor substrate, and

forming a weakened zone in the epitaxial layer during an implantation step.

14. The method of claim 13 , wherein the recycled donor substrate includes at least part of the epitaxial layer.

15. The method of claim 14 , wherein the epitaxial layer on the recycled donor substrate has a thickness that is greater than 100 nm.