Process for fabricating a structure for epitaxy without an exclusion zone
A process for fabricating a composite structure for epitaxy, including at least one crystalline growth seed layer of semiconductor material on a support substrate, with the support substrate and the crystalline growth seed layer each having, on the periphery of their bonding face, a chamfer or an edge rounding zone. The process includes at least one step of wafer bonding the crystalline growth seed layer directly onto the support substrate and at least one step of thinning the crystalline growth seed layer. After thinning, the crystalline growth seed layer has a diameter identical to its initial diameter.
1. A multilayer structure comprising a composite structure that has a support substrate,
wherein the support substrate has a chamfer or edge rounding on each of its two surfaces that are uniform about the periphery of the support substrate, and
a crystalline growth seed layer of semiconductor material bonded to the support substrate
wherein the crystalline growth seed layer has:
a chamfer or edge rounding on at least one of its two surfaces, that is uniform about the periphery of the crystalline growth seed layer substrate,
a thickness of 5 μm to 100 μm, a defect density of less than 10 9 /cm 2 on its surface, and
a diameter that is the same as that of the support substrate.
2. The multilayer structure as claimed in claim 1 , which further comprises a layer of semiconductor material formed by epitaxial growth on the crystalline growth seed layer.
3. The multilayer structure as claimed in claim 2 , which further comprises a nucleation layer of semiconductor material formed by epitaxial growth between the layer of semiconductor material formed by epitaxial growth and the crystalline growth seed layer.
4. The multilayer structure as claimed in claim 3 , wherein the nucleation layer has a thickness of between 10 nm and 10 micrometers.
5. The multilayer structure as claimed in claim 3 , wherein the material of the crystalline seed layer has a thermal expansion coefficient that is close to that of the support substrate.
6. The multilayer structure as claimed in claim 2 , wherein the layer of semiconductor material has a thickness of at least 100 μm or wherein the layer of semiconductor material and the crystalline growth seed layer together have a thickness of at least 100 μm.
7. The multilayer structure as claimed in claim 2 , wherein the layer of semiconductor material has a diameter that is the same as that of the crystalline growth seed layer and that of the support substrate.
8. The multilayer structure as claimed in claim 2 , wherein layer of semiconductor material is a GaN layer or a binary, ternary or quaternary Group III/N material, or a Group III/V material or a Group IV material.
9. The multilayer structure as claimed in claim 1 , wherein the support substrate is a material of: polycrystalline AIN, single-crystal or polycrystalline GaN, single-crystal or polycrystalline SiC, sapphire, a ceramic, or a metal alloy, and wherein the chamfer of the support substrate or the crystalline growth seed layer or both conform to SEMI™ standards.
10. The multilayer structure as claimed in claim 1 , wherein the crystalline growth seed layer of semiconductor material is a material of: single-crystal Si, single-crystal SiC, single-crystal sapphire, or binary, ternary or quaternary Group III/V or Group III/N material.
11. The multilayer structure as claimed in claim 1 , which further comprises a bonding layer between the support substrate and the crystalline growth seed layer of semiconductor material.
12. The multilayer structure as claimed in claim 1 , wherein the bonding layer is an oxide, diamond, AIN or a silicon nitride layer.