Techniques for forming optoelectronic devices
Embodiments relate to use of a particle accelerator beam to form thin films of material from a bulk substrate. In particular embodiments, a bulk substrate (e.g. donor substrate) having a top surface is exposed to a beam of accelerated particles. In certain embodiments, this bulk substrate may comprise GaN; in other embodiments this bulk substrate may comprise Si, SiC, or other materials. Then, a thin film or wafer of material is separated from the bulk substrate by performing a controlled cleaving process along a cleave region formed by particles implanted from the beam. In certain embodiments this separated material is incorporated directly into an optoelectronic device, for example a GaN film cleaved from GaN bulk material. In some embodiments, this separated material may be employed as a template for further growth of semiconductor materials (e.g. GaN) that are useful for optoelectronic devices.
1. A method comprising:
providing a GaN workpiece;
introducing a plurality of particles into a surface of the GaN workpiece to form a cleave region in the GaN workpiece;
bonding the surface of the GaN workpiece to an insulating substrate, wherein the bonding comprises applying a deposited silicon dioxide film by a spin-on technique and an aluminum nitride film prior to the introducing, wherein the substrate includes a light scattering interface comprising a dielectric filler co-planar with islands of a metal layer to enhance light extraction in light emitting diode applications;
prior to the introducing, causing the applied silicon dioxide film to undergo a thermal anneal to densify the silicon dioxide film;
applying energy to cleave a detached thickness of GaN, from a remainder of the GaN workpiece;
processing the substrate bearing the detached thickness of GaN at a temperature of about 1000° C. to grow additional GaN over the detached thickness by metal-organic chemical vapor deposition.
2. The method as in claim 1 wherein the insulating substrate comprises sapphire.
3. The method as in claim 1 wherein the insulating substrate comprises amorphous aluminum nitride.
4. The method as in claim 1 wherein the applied films undergo an etch step prior to bonding to enhance bond strength.
5. The method as in claim 1 wherein:
the insulating substrate further comprises a reflecting layer that is positioned between the detached thickness of GaN and the substrate following the application of energy, wherein the reflecting layer comprises the metal layer; and
processing the substrate to create a light emitting diode device.
6. The method as in claim 1 wherein the GaN is doped p-type or n-type.
7. The method as in claim 1 wherein the GaN is unintentionally doped.
8. The method as in claim 1 wherein the processing comprises performing polishing and/or other surface treatment.
9. The method as in claim 8 wherein the other surface treatment includes annealing.
10. The method as in claim 8 wherein the other surface treatment includes a plasma etch.
11. The method as in claim 8 wherein the other surface treatment includes a chemical etch.
12. The method as in claim 1 wherein the filler comprises the deposited silicon dioxide film.
13. The method as in claim 1 wherein the filler comprises the deposited aluminum nitride film.