Bond and release layer transfer process
Embodiments transfer thin layers of material utilized in electronic devices (e.g., GaN for optoelectronic devices), from a donor to a handle substrate. Certain embodiments employ bond-and-release system(s) where release occurs along a cleave plane formed by implantation of particles into the donor. Some embodiments may rely upon release by converting components from solid to liquid under carefully controlled thermal conditions (e.g., solder-based materials and/or thermal decomposition of Indium-containing materials). Some embodiments utilize laser-induced film release processes using epitaxially grown or implanted regions as an optically absorptive region. A single bond-and-release sequence may involve processing an exposed N-face of GaN material. Multiple bond-and-release sequences (involving processing an exposed Ga-face of GaN material) may be employed in series, for example utilizing a temporary handle substrate as an intermediary. Particular embodiments form template blanks of high quality GaN suitable for manufacturing High Brightness-Light Emitting Diode (HB-LED) devices.
1. A method comprising:
providing a donor comprising GaN and having a cleave plane formed by implanted particles wherein a GaN film is above the cleave plane;
bonding the donor to a transfer substrate utilizing a bond-and-release system in a first state, wherein a reflector layer comprising deposited aluminum metal is disposed between the GaN film and the bond-and-release system;
using a thermal cleave process to separate the donor along the cleave plane to produce the transfer substrate including said GaN film;
bonding the transfer substrate including GaN to a permanent handle; and
changing a component of the bond-and-release system into a second state to release the permanent handle including the GaN from the transfer substrate.
2. A method as in claim 1 wherein the component of the bond-and-release system comprises indium.
3. A method as in claim 1 wherein the transfer substrate comprises aluminum nitride or mullite.
4. A method as in claim 1 wherein the permanent substrate comprises mullite or aluminum nitride.
5. A method as in claim 1 wherein the coefficient of thermal expansion (CTE) of the transfer substrate within the temperature range of 30-400° C. is chosen to be within +/−0.75ppm/° C. of the CTE of the GaN bond surface.
6. A method as in claim 1 wherein the component of the bond-and-release system is changed by thermal decomposition by applying energy through the transfer substrate.
7. A method as in claim 1 wherein the component of the bond-and-release system undergoes a phase change by applying energy through the transfer substrate.
8. A method as in claim 1 further comprising providing a release layer on the transfer substrate.
9. A method as in claim 1 further comprising providing a release layer on the donor substrate.
10. A method as in claim 1 further comprising providing a release layer comprising InN.
11. A method as in claim 1 further comprising providing an adhesion layer on the transfer substrate.
12. A method as in claim 1 wherein the thermal cleave process is a global heating process.
13. A method as in claim 1 wherein the thermal cleave process is a beam process.
14. A method as in claim 13 wherein the beam process is a laser beam.
15. A method as in claim 14 wherein the laser beam is a pulsed laser with a center wavelength between 250 nm to 850 nm.
16. A method as in claim 14 wherein the laser beam has a pulse width between 100 fsec and 100 nsec.
17. A method comprising:
providing a donor comprising GaN and having a cleave plane formed by implanted particles wherein a GaN film is above the cleave plane;
bonding the donor to a handle substrate including a reflector layer comprising deposited aluminum metal;
using a thermal cleave process to separate the donor along the cleave plane to produce a transfer substrate including said GaN film, wherein the thermal cleave process is a beam process and the beam process is a laser beam, and wherein the laser beam has a pulse width between 100 fsec and 100 nsec.
18. A method as in claim 17 wherein the handle substrate comprises mullite or aluminum nitride.
19. A method as in claim 17 wherein the coefficient of thermal expansion (CTE) of the handle substrate within the temperature range of 30-400° C. is chosen to be within +/−0.75ppm/° C. of the CTE of the GaN bond surface.
20. A method as in claim 17 wherein the thermal cleave process further comprises a global heating process.
21. A method as in claim 17 wherein the laser beam is a pulsed laser with a center wavelength between 250 nm to 850 nm.
22. A method as in claim 17 wherein the transfer substrate comprises aluminum nitride or mullite.
23. A method as in claim 17 wherein the coefficient of thermal expansion (CTE) of the transfer substrate within the temperature range of 30-400° C. is chosen to be within +/−0.75ppm/° C. of the CTE of the GaN bond surface.
24. A method as in claim 17 further comprising providing a release layer on the transfer substrate.
25. A method as in claim 17 further comprising providing a release layer comprising InN.
26. A method as in claim 17 further comprising providing an adhesion layer on the transfer substrate.