Methods for fabricating compound material wafers

1. A method for preparing a reconditioned donor substrate for recycling as an initial donor substrate, which comprises:

providing a remainder substrate from an initial donor substrate wherein the remainder substrate has a detachment surface where at least one transfer layer was detached and an opposite surface; and

depositing an additional layer onto the opposite surface of the remainder substrate to increase its thickness to be approximately the same as that of the initial donor substrate to form a reconditioned substrate for recycling as a donor substrate depositing a protective layer on the detachment surface prior to depositing the additional layer onto the opposite surface of the reminder substrate.

2. The method of claim 1 , wherein the protective layer is made of an oxide material or a nitride material.

3. The method of claim 1 , which further comprises removing the protective layer prior to recycling the reconditioned substrate as the donor substrate.

4. The method of claim 1 , which further comprises polishing or cleaning the opposite surface of the remainder substrate before depositing the additional layer onto it.

5. The method of claim 1 , wherein the remainder substrate is made of at least one of gallium nitride, silicon carbide, germanium, aluminum nitride, or diamond.

6. The method of claim 1 , wherein the depositing of the additional layer onto the opposite surface of the remainder substrate is performed by homoepitaxy.

7. The method of claim 6 , wherein the homoepitaxial additional layer is deposited by at least one of a metal organic chemical vapor deposition method, a hybrid vapor phase epitaxy method, or a molecular beam epitaxy method.

8. The method of claim 6 , wherein the homoepitaxial additional layer has a dislocation density of less than about 1×10 7 per cm 2 .

9. The method of claim 6 , wherein the additional layer has a better crystalline quality than that of the remainder substrate.

10. The method of claim 6 , wherein the additional layer has a lower crystalline quality than that of the remainder substrate.

11. The method of claim 6 , wherein the additional layer has a thickness from about 10 to 100 micrometers.

12. The method of claim 1 wherein the reminder substrate is provided by

providing a donor substrate having a weakened zone therein that defines the transfer layer;

detaching the donor substrate at the weakened zone to transfer the transfer layer onto another substrate, thus providing the remainder substrate having a surface where the transfer layer was detached.