Process for transferring films
A process of transferring a layer of a first material from a first substrate, having defects in a zone close to the surface, onto a host substrate made of a second material includes a step of thinning the first substrate in order to form a first thinned substrate, an ion or atom implantation in the first substrate in order to form an implantation plane therein, delimiting the layer to be transferred, and a transfer of the layer onto the host substrate by fracturing the substrate along the implantation plane.
1. A process for forming a layer on a host substrate, the process comprising:
a) depositing a monocrystalline layer onto a deposition substrate to form a deposited layer, comprising a superficial portion having a first defect density, the defects comprising crystalline defects or composition homogeneity defects, and a buried portion, having fewer defects than the superficial portion;
b) thinning the deposited layer by removing the superficial portion and allowing the buried portion to remain to form a thinned layer, wherein thinning the deposited layer comprises removing at least 500 nm of material from the monocrystalline layer, and wherein the thinned layer has a second defect density that is less than the first defect density;
c) implanting ions or atoms in the deposition substrate after thinning the deposited layer to form an implantation zone;
d) transferring the thinned layer onto the host substrate;
and
e) fracturing the deposition substrate along the implantation zone.
2. The process according to claim 1 further comprising, before step c), or before step d), a step of forming at least one intermediate layer.
3. The process according to claim 2 , wherein forming at least one intermediate layer comprises forming one of more layers of silicon oxide, silicon nitride, or aluminum oxide.
4. The process according to claim 1 , wherein implanting ions or atoms comprises implanting a dose between 1×10 16 cm −2 and 4×10 17 cm −2 .
5. The process according to claim 1 , wherein the host substrate comprises one of glass, garnet, sapphire, diamond or ceramic.
6. The process according to claim 1 , wherein the host substrate further includes a layer to assist with bonding.
7. The process according to claim 1 , wherein the deposited layer has a thickness greater than 1 μm before step b), and the thinned layer has a thickness below 1 μm after step b).
8. The process according to claim 1 , wherein depositing a monocrystalline layer comprises epitaxial growth of the layer on the deposition substrate.
9. The process according to claim 1 , wherein depositing a monocrystalline layer comprises one of liquid phase epitaxy, deposition by laser ablation of a target, cathode sputtering, or ion beam sputtering.
10. The process according to claim 1 , wherein the material of the deposited layer comprises garnet.
11. The process according to claim 1 , wherein the material of the deposited layer comprises ferromagnetic garnet doped with bismuth.
12. The process according to claim 10 or 11 , wherein the deposition substrate comprises GGG, NdGG or SGGG.
13. The process according to claim 1 , wherein transferring the thinned layer comprises direct or molecular bonding.
14. The process according to claim 1 , wherein the host substrate includes one or more optical components.
15. The process according to claim 1 , wherein the host substrate includes one or more waveguides.
16. The process according to claim 1 , wherein the host substrate comprises a layer of III-V semiconductor material or glass having a variation in ion concentration.
17. A process for forming a layer of garnet on a host substrate, the process comprising:
a) depositing a monocrystalline layer of garnet onto a deposition substrate to form a deposited layer comprising a superficial portion having a first defect density, the defects comprising crystalline defects or composition homogeneity defects, and a buried portion having fewer defects than the superficial portion;
b) thinning the deposited layer, such that a superficial portion of material having a thickness at least 500 nm is removed, and allowing the buried portion to remain, forming a thinned layer, wherein the thinned layer has a second defect density that is less than the first defect density;
c) implanting ions or atoms in the deposition substrate after thinning the deposited layer to form an implantation zone;
d) transferring the thinned layer onto the host substrate, the host substrate comprising glass, garnet, sapphire, diamond, or ceramic;
and
e) fracturing the deposition substrate along the implantation zone.
18. A process for forming a layer on a host substrate, the process comprising:
a) depositing a monocrystalline layer onto a deposition substrate to form a deposited layer, comprising a superficial portion having a first defect density, the defects comprising crystalline defects or composition homogeneity defects, and a buried portion, having fewer defects than the superficial portion;
b) thinning the deposited layer by removing the superficial portion and allowing the buried portion to remain to form a thinned layer, wherein the thinned layer has a thickness of less than about 1 micron and a second defect density that is less than the first defect density;
c) implanting ions or atoms in the deposition substrate after thinning the deposited layer to form an implantation zone;
d) transferring the thinned layer onto the host substrate;
and
e) fracturing the deposition substrate along the implantation zone.
19. The process according to claim 18 , wherein the deposited layer has a thickness greater than 1 μm before step b), and the thinned layer has a thickness below 1 μm after step b).
20. The process according to claim 18 , wherein transferring the thinned layer comprises direct or molecular bonding.
21. The process according to claim 18 , wherein thinning the deposited layer comprises removing at least 500 nm of material from the monocrystalline layer.