Optoelectronic device with dielectric layer and method of manufacture
An optoelectronic device and a method for fabricating the optoelectronic device are disclosed. The optoelectronic device comprises a p-n structure, a patterned dielectric layer comprising a dielectric material and a metal layer disposed on the dielectric layer. The metal layer makes one or more contact to the p-n structure through the patterned dielectric layer. The dielectric material may be chemically resistant to acids and may provide adhesion to the p-n structure and the metal layer. The method for fabricating an optoelectronic device comprises providing a p-n structure, providing a dielectric layer on the p-n structure and providing a metal layer on the dielectric layer and then lifting the device off the substrate, such that after the lift off the p-n structure is closer than the patterned dielectric layer to a front side of the device; wherein the device comprises the p-n structure, the patterned dielectric layer, and the metal layer.
1. A method for fabricating an optoelectronic device, the method comprising:
providing a p-n structure on a substrate;
patterning a dielectric layer on the p-n structure, the patterned dielectric layer is patterned to form a plurality of apertures, and each aperture extends through the patterned dielectric layer and to the p-n structure; and
disposing a metal layer on the dielectric layer, the patterned dielectric layer provides adhesion to the p-n structure and the metal layer;
wherein the metal layer as deposited makes electrical contact to the p-n structure at a plurality of locations, the metal layer including a plurality of metallic reflector protrusions each of which extends from the metal layer into a respective aperture from the plurality of apertures to fill the respective aperture, and the plurality of metallic reflector protrusions provide the plurality of locations at which the metal layer has electrical contact to the p-n structure; and
then lifting the optoelectronic device off the substrate, such that after the lift off the p-n structure is closer than the patterned dielectric layer to a front side of the optoelectronic device which is to face incident light, wherein the optoelectronic device comprises the p-n structure, the patterned dielectric layer, and the metal layer.
2. The method of claim 1 , wherein the p-n structure comprises a Group III-V semiconductor layer.
3. The method of claim 1 , wherein the p-n structure comprises a physically textured surface.
4. The method of claim 1 , further comprising:
disposing, after the lifting of the optoelectronic device off the substrate, metallic contacts to the front side of the optoelectronic device, positioned such that the metallic contacts to the front side of the optoelectronic device and the plurality of locations at which the metal layer makes contact to the p-n structure are offset to prevent short circuits.
5. The method of claim 1 , wherein the patterned dielectric layer comprises dielectric materials that are resistant to etching by hydrochloric acid, sulfuric acid, or hydrofluoric acid during an epitaxial lift off (ELO) process for the lifting the optoelectronic device off the substrate.
6. The method of claim 5 , wherein the dielectric materials are organic materials comprising any of polyolefin, polycarbonate, polyester, epoxy, fluoropolymer, derivatives thereof and combinations thereof.
7. The method of claim 5 , wherein the dielectric materials are inorganic comprising any of arsenic trisulfide, arsenic selenide, a-alumina (sapphire), magnesium fluoride, derivatives thereof and combinations thereof.
8. The method of claim 1 , wherein the dielectric layer is provided for patterning by using any of spin coating, dip coating, spray coating, physical vapor deposition (PVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), powder coating, sol gel, ion-beam assisted chemical vapor deposition (IBRD CVD), chemical bath deposition, inkjet printing, screen printing and lamination.
9. The method of claim 1 , wherein the patterning of the dielectric layer is done by using any of wet etching, dry etching, disposing the dielectric layer using inkjet printing, photolithography, shadow masking, imprint lithography, laser ablation and screen printing.
10. The method of claim 1 , further comprising optical texturing of the patterned dielectric layer.
11. The method of claim 10 , wherein the optical texturing is accomplished by disposing particles from the group consisting of alumina, titania, silica, derivatives thereof and combinations thereof; wherein the particles are disposed any of between the p-n structure and the dielectric layer, within the dielectric layer, between the dielectric layer and the metal layer or a combination thereof.
12. The method of claim 1 , further comprising physical texturing of a surface of the patterned dielectric layer.
13. The optoelectronic device of claim 12 , wherein the physical texturing of the surface of the patterned dielectric layer is achieved by any of etching, exposure to a plasma, particle blasting, mechanical imprinting, laser ablation, and a combination thereof, and wherein when the etching is used the etching is a wet etch or a dry etch.
14. The method of claim 1 , wherein the metal layer further comprises a metallic reflector layer from which the metallic reflector protrusions extend.
15. The method of claim 14 , wherein the metallic reflector layer comprises a metal selected from the group consisting of silver, gold, aluminum, nickel, copper, platinum, palladium, molybdenum, tungsten, titanium, chromium, alloys thereof, derivatives thereof, and combinations thereof.
16. The method of claim 1 , wherein the metallic reflector protrusions comprise a metal selected from the group consisting of silver, gold, aluminum, nickel, copper, platinum, palladium, molybdenum, tungsten, titanium, chromium, alloys thereof, derivatives thereof, and combinations thereof.
17. The method of claim 1 , wherein the p-n structure comprises multiple p-n junctions.