Methods for making substrates and substrates formed therefrom

Abstract

A method for making substrates for use in optics, electronics, or opto-electronics. The method may include transferring a seed layer onto a receiving support and depositing a useful layer onto the seed layer. The thermal expansion coefficient of the receiving support may be identical to or slightly larger than the thermal expansion coefficient of the useful layer and the thermal expansion coefficient of the seed layer may be substantially equal to the thermal expansion coefficient of the receiving support.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be better understood by reference to the following drawings, wherein like references numerals represent like elements. The drawings are merely exemplary to illustrate certain features that may be used singularly or in combination with other features and the present invention should not be limited to the embodiments shown.

FIG. 1 is a schematic illustration of the steps of an exemplary embodiment of a method for making a substrate; and

FIG. 2 is a schematic illustration of the steps of an alternative exemplary embodiment of a method for making a substrate.

Claims

1. A method for making substrates comprising: providing a donor substrate and a receiving substrate, wherein the receiving substrate has a thermal expansion coefficient;operably connecting the donor substrate to the receiving substrate;forming a seed layer on the receiving substrate, wherein the seed layer has a surface and a thermal expansion coefficient; andepitaxy of a useful layer on the seed layer, wherein the useful layer has a thermal expansion coefficient;wherein the thermal expansion coefficient of the receiving substrate is equal to or greater than the thermal expansion coefficient of the useful layer, andwherein the thermal expansion coefficient of the seed layer is about the same as the thermal expansion coefficient of the receiving substrate so that the seed layer and the receiving support expand in substantially the same way to avoid stressing or deforming the seed layer.

2. The method of claim 1 wherein the seed layer forms a surface portion of the donor substrate, the method further comprising forming a weakened area in the donor substrate beneath the seed layer and detaching the donor substrate from the seed layer at the weakened area so that the seed layer remains operably connected to the receiving substrate.

3. The method of claim 2, wherein the step of forming a weakened area comprises implanting atomic species into the donor substrate.

4. The method of claim 1, wherein the step of operably connecting the donor substrate to the receiving substrate includes forming a bonding layer between the seed layer and the receiving substrate.

5. The method of claim 4 further comprising preparing the surface of the seed layer, wherein the preparation step is selected from at least one of the group consisting of polishing, annealing, sacrificial oxidation interface operations and etching.

6. The method of claim 4 further comprising providing a supporting substrate of a material selected from the group consisting of a semi-conductor, metal, plastic and glass, and operably connecting the useful layer to the supporting substrate.

7. The method of claim 6 further comprising detaching the seed layer, the useful layer and the supporting substrate from the receiving substrate and subsequently removing the seed layer from the useful layer and the supporting substrate.

8. The method of claim 7 wherein the step of detaching comprises performing at least one of the operations selected from the groups consisting of heat treatment, application of stresses, irradiation and etching.

9. The method of claim 6, wherein the step of operably connecting the useful layer to the supporting substrate comprises forming a bonding layer between the useful layer and the supporting substrate, wherein the bonding layer is selected from the group consisting of insulating layers, organic layers, metal interfaces and seals.

10. The method of claim 10 further comprising burying a structure in the second bonding layer.

11. The method of claim 1 further comprising forming the seed layer from a material for which the thermal expansion coefficient is (1+ε) times the thermal expansion coefficient of the receiving substrate, and forming the useful layer from a material for which the thermal expansion coefficient is greater than or equal to (1±ε′) times the thermal expansion coefficient of the receiving substrate.

12. The method of claim 1 which further comprises forming at least one of the seed layer and the receiving substrate from a material selected from the group consisting of silicon, germanium, silicon carbide, GaN, AlN and sapphire, and optionally where the chemical composition of the seed layer and that of the receiving substrate are identical.

13. The method of claim 1 further comprising detaching the seed layer and the useful layer from the receiving substrate by performing at least one of the operations selected from the group consisting of heat treatment, application of mechanical, thermal or electrostatic stresses, irradiation and etching.

14. The method of claim 22 further comprising performing an operation selected from the group consisting of dry, wet, gas, chemical and plasma etching or irradiation using a laser.

15. The method of claim 1 further comprising removing the seed layer from the useful layer.

16. The method of claim 1 further comprising reusing the receiving substrate to make another substrate.

17. The method of claim 1, wherein the step of forming the seed layer comprises thinning the donor substrate after bringing the donor substrate into contact with the receiving substrate.

18. A method for making substrates comprising: providing a donor substrate and a receiving support;forming a seed layer from the donor substrate;transferring the seed layer onto the receiving support;forming a useful layer on the seed layer;wherein the thermal expansion coefficient of the receiving support is equal to or greater than the thermal expansion coefficient of the useful layer, andwherein the thermal expansion coefficient of the seed layer is about equal to the thermal expansion coefficient of the receiving support.

19. The method of claim 18 wherein forming the seed layer comprises inserting atomic species into the donor substrate and forming a weakened area beneath the seed layer.

20. The method of claim 18 wherein forming a useful layer comprises epitaxy of the useful layer on the seed layer.

21. The method of claim 18 wherein transferring the seed layer to the receiving support comprises bonding the donor substrate to the receiving support and detaching the seed layer and the useful layer from the receiving support.

22. The method of claim 21 further comprising removing the seed layer from the useful layer and transferring the useful layer onto a supporting substrate.

23. A substrate comprising: a receiving support having a thermal expansion coefficient;a seed layer having a thermal expansion coefficient, wherein the seed layer is operably connected to the receiving support; anda useful layer having a thermal expansion coefficient, the useful layer being operably connected to the seed layer;wherein the thermal expansion coefficient of the receiving support is greater than or equal to the thermal expansion coefficient of the useful layer, andwherein the thermal expansion coefficient of the seed layer is about equal to the thermal expansion coefficient of the receiving support so that the seed layer and the receiving support expand in substantially the same way to avoid stressing or deforming the seed layer.

24. The substrate of claim 23, wherein the seed layer is made of a material for which the thermal expansion coefficient is equal to (1+ε) times the thermal expansion coefficient of the receiving support.

25. The substrate of claim 23 wherein the useful layer is made of a material for which the thermal expansion coefficient is greater than or equal to (1±ε′) times the thermal expansion coefficient of the receiving support.

26. The substrate of claim 23, wherein the at least one of the seed layer and the receiving support is made of a material selected from the group consisting of silicon, germanium, silicon carbide, GaN, AlN and sapphire and optionally where the chemical composition of the seed layer and that of the receiving substrate are identical.

27. The substrate of claim 23 further comprising a supporting substrate comprising a material selected from the group consisting of semiconductors, plastic, glass and metal, and optionally including a bonding layer connecting the supporting substrate and the useful layer.

28. The substrate of claim 27 further comprising a structure buried in the bonding layer.

29. The substrate of claim 23 further comprising a bonding layer connecting the seed layer and the receiving support, wherein the bonding layer is comprised of a material selected from the group consisting of insulating layers, organic layers, metal interfaces and sealing layers.

30. The substrate of claim 23, wherein the seed layer and the useful layer has a thickness of at least 50 μm.