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A method for manufacturing a free-standing substrate made of a semiconductor material. A first assembly is provided and it includes a relatively thinner nucleation layer of a first material, a support of a second material, and a removable bonding interface defined between facing surfaces of the nucl

A method for manufacturing a free-standing substrate made of a semiconductor material. A first assembly is provided and it includes a relatively thinner nucleation layer of a first material, a support of a second material, and a removable bonding interface defined between facing surfaces of the nucleation layer and support. A substrate of a relatively thicker layer of a third material is grown, by epitaph on the nucleation layer, to form a second assembly with the substrate attaining a sufficient thickness to be free-standing. The third material is preferably a monocrystalline material. Also, the removable character of the bonding interface is preserved with at least the substrate being heated to an epitaxial growth temperature. The coefficients of thermal expansion of the second and third materials are selected to be different from each other by a thermal expansion differential, determined as a function of the epitaxial growth temperature or subsequent application of external mechanical stresses, such that, as the second assembly cools from the epitaxial growth temperature, stresses are induced in the removable bonding interface to facilitate detachment of the nucleation layer from the substrate.

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What is claimed is: 1. A method for manufacturing a free-standing substrate made of a semiconductor material, which comprises: providing a first assembly by bonding of a nucleation layer of a first material to a support of a second material at a bonding interface being defined and located between f

What is claimed is: 1. A method for manufacturing a free-standing substrate made of a semiconductor material, which comprises: providing a first assembly by bonding of a nucleation layer of a first material to a support of a second material at a bonding interface being defined and located between facing surfaces of the nucleation layer and the support, wherein the nucleation layer is applied onto the support by direct bonding with molecular adhesion; growing, by epitaxy on the nucleation layer, a substrate of a layer of a third material to form a second assembly with the substrate attaining a sufficient thickness to be free-standing, with at least the substrate being heated to an epitaxial growth temperature, wherein the third material is a wide bandgap material; and selecting the coefficients of thermal expansion of the second and third materials to be different from each other by a thermal expansion differential, determined as a function of the epitaxial growth temperature or subsequent application of external mechanical stresses, such that, as the second assembly cools from the epitaxial growth temperature, stresses are induced in the bonding interface to facilitate detachment of the nucleation layer and the substrate from the support. 2. The method of claim 1, wherein the wide bandgap material is silicon carbide. 3. The method according to claim 1, wherein the coefficients of thermal expansion of the second and third materials are selected to be sufficiently different from each other so that the nucleation layer and substrate become detached as the second assembly cools to ambient from the epitaxial growth temperature. 4. The method according to claim 1, which further comprises applying a thermal treatment to raise stresses at the bonding interface to assist in the detachment of the nucleation layer and the substrate. 5. The method according to claim 1, which further comprises applying an external stress to assist in the detachment of the nucleation layer and the substrate by increasing the stress between the materials at the bonding interface. 6. The method according to claim 1, wherein the substrate is a monocrystalline material deposited at least in part by hydride vapor phase epitaxy (HPVE). 7. The method according to claim 1, wherein removal of the bonding interface is facilitated by effecting a treatment for augmenting the roughness of the facing surface of at least one of the nucleation layer or the support. 8. The method according to claim 7, wherein the treatment for augmenting surface roughness is carried out by chemical attack or etching. 9. The method according to claim 1, wherein removal of the bonding interface is facilitated by effecting a treatment for decreasing hydrophilicity of the facing surface of at least one of the nucleation layer or the support. 10. The method according to claim 1, wherein the epitaxial growing of the second material includes initially providing a fine nucleation layer on the nucleation layer in order to improve the crystal quality of the deposited third material of the substrate. 11. The method according to claim 10, wherein the tine nucleation layer is provided by metal organic chemical vapor deposition (MOCVD) epitaxy or by molecular beam (MBE) epitaxy. 12. The method according to claim 1, which further comprises eliminating the nucleation layer after detachment so that the substrate becomes a free-standing structure. 13. The method according to claim 1, which further comprises, prior to bonding the nucleation layer onto the support, forming the nucleation layer by implantation of an atomic species into a source substrate to a defined depth to form an embrittled zone that defines a boundary of the nucleation layer in the source substrate. 14. The method according to claim 13, wherein the source substrate comprises a monocrystalline or polycrystalline wide bandgap material. 15. The method according to claim 14, wherein the wide bandgap material of the source substrate is gallium nitride (GaN) or aluminum nitride (AIN). 16. The method according to claim 1, which further comprises detaching the nucleation layer and the substrate from the support. 17. The method according to claim 16, which further comprises eliminating the nucleation layer after detachment so that the substrate becomes a free-standing structure. 18. A method for manufacturing a free-standing substrate made of a semiconductor material, which comprises: providing a first assembly by bonding of a nucleation layer of a first material to at least one intermediate bonding layer present on a support of a second material at a bonding interface being defined and located between facing surfaces of the nucleation layer and the intermediate bonding layer of the support, wherein the nucleation layer is applied onto the intermediate bonding layer of the support by direct bonding with molecular adhesion; growing, by epitaxy on the nucleation layer, a substrate of a layer of a third material to form a second assembly with the substrate attaining a sufficient thickness to be free-standing, with at least the substrate being heated to an epitaxial growth temperature, wherein the third material is a wide bandgap material; and selecting the coefficients of thermal expansion of the second and third materials to be different from each other by a thermal expansion differential, determined as a function of the epitaxial growth temperature or subsequent application of external mechanical stresses, such that, as the second assembly cools from the epitaxial growth temperature, stresses are induced in the bonding interface to facilitate detachment of the nucleation layer and the substrate from the intermediate bonding layer and the support. 19. The method according to claim 18, wherein the intermediate bonding layer is positioned adjacent the nucleation layer and a second intermediate bonding layer is positioned adjacent the support. 20. The method according to claim 19, wherein at least one of the intermediate bonding layers is a layer of silicon oxide or silicon nitride. 21. A method for manufacturing a free-standing substrate made of a semiconductor material, which comprises: forming a nucleation layer by implantation of an atomic species into a source substrate to a defined depth to form an embrittled zone that defines a boundary of the nucleation layer from a remainder of the source substrate; providing a first assembly by bonding the nucleation layer of a first material to a support of a second material, at a bonding interface being defined and located between facing surfaces of the nucleation layer and the support; detaching the nucleation layer at the embrittled zone to remove the remainder of the source substrate and provide the nucleation layer bonded to the support; growing, by epitaxy on the nucleation layer, a substrate of a layer of a third material to form a second assembly with the substrate attaining a sufficient thickness to be free-standing, with at least the substrate being heated to an epitaxial growth temperature; and selecting the coefficients of thermal expansion of the second and third materials to be different from each other by a thermal expansion differential, determined as a function of the epitaxial growth temperature or subsequent application of external mechanical stresses, such that, as the second assembly cools from the epitaxial growth temperature, stresses are induced in the bonding interface to facilitate detachment of the nucleation layer and the substrate from the support. 22. The method according to claim 21, wherein the third material has a band gap value above 1.5 eV.