Methods of fabricating integrated optoelectronic devices
View Patent ↗This disclosure concerns methods for fabrication of integrated high speed optoelectronic devices. In one example of such a method, a device region that includes a top surface and a bottom surface is formed on a top surface of a substrate. The device region may take the form of an optical emitter, such as a VCSEL, or a detector, such as a photodiode. Next, an isolation region is formed that is configured such that the device region is surrounded by the isolation region. A superstrate is then disposed on the top surface of the device region. Finally, a micro-optical device, such as a lens, is placed on a top surface of the superstrate.
1. A method for fabricating an optoelectronic device, comprising:
forming, upon a top surface of a substrate, a device region that includes a top surface and a bottom surface;
forming an isolation region configured such that the device region is surrounded by the isolation region;
providing a superstrate on the top surface of the device region, the superstrate including a top surface; and
disposing a micro-optical device on the top surface of the superstrate.
2. The method as recited in claim 1 , wherein forming the device region comprises depositing a plurality of epitaxial layers.
3. The method as recited in claim 1 , wherein the device region is formed using MOCVD.
4. The method as recited in claim 1 , wherein the device region comprises one of: an optical emitter; or, an optical detector.
5. The method as recited in claim 1 , wherein the isolation region is formed by ion implantation of a portion of the device region and wherein formation of the isolation region includes definition of an active region.
6. The method as recited in claim 1 , wherein provision of a superstrate on the top surface of the device region comprises one of: formation of a superstrate on the top surface of the device region; or, attachment of a superstrate wafer to the top surface of the device region.
7. The method as recited in claim 1 , wherein the superstrate comprises a material that is optically transparent with regard to a wavelength associated with the device region.
8. The method as recited in claim 1 , wherein the micro-optical device comprises one of: a collimating lens; a focusing lens; and, a refractive lens.
9. The method as recited in claim 1 , further comprising bonding an integrated circuit to the bottom surface of the device region.
10. A method for fabricating an optoelectronic device, comprising:
forming, upon a top surface of a substrate, a device region that includes a top surface and a bottom surface;
forming, by ion implantation of a portion of the device region, a top isolation region configured such that the device region is surrounded by the top isolation region;
forming a p-type contact metal that extends across an unimplanted region of the device region and onto the surrounding top isolation region;
providing a superstrate on the top surface of the device region, the superstrate including a top surface;
removing the substrate;
forming, by ion implantation of a portion of the device region, a bottom isolation region configured and arranged to electrically isolate contacts of the device region;
forming an n-type contact metal that extends across an unimplanted region of the device region and onto the bottom isolation region;
forming a thru-epi via by etching an exposed surface of the device region through to the p-type contact metal;
forming a thru-epi metal such that the thru-epi metal traverses through the thru-epi via and contacts the p-type contact metal;
forming a first bond pad on the bottom isolation region, and forming a second bond pad on the n-type contact metal;
disposing a micro-optical device on the top surface of the superstrate; and
bonding an integrated circuit to the bottom surface of the device region.
11. The method as recited in claim 10 , wherein forming the device region comprises:
forming an n-type epilayer on the top surface of the substrate;
forming an active layer on the n-type epilayer; and
forming a p-type epilayer on the active layer.
12. The method as recited in claim 11 , wherein formation of the top isolation region is performed by hydrogen implantation of the p-type epilayer; and, a portion of the n-type epilayer.
13. The method as recited in claim 10 , wherein the p-contact metal is formed using E-beam deposition.
14. The method as recited in claim 10 , further comprising formation of emitter/illumination window in the p-contact metal.
15. The method as recited in claim 10 , wherein the superstrate is adhered to the device region with an optically transparent adhesive.
16. The method as recited in claim 10 , wherein the n-contact metal is formed using E-beam deposition.
17. The method as recited in claim 10 , wherein the thru-epi via is formed by RIE.
18. The method as recited in claim 10 , wherein forming a thru-epi metal comprises electro-plating gold.
19. The method as recited in claim 10 , wherein the bond pads are bump bonded to matching pads of the integrated circuit.
20. A method for fabricating an optoelectronic device, comprising:
forming, upon a top surface of a substrate, a device region;
forming an isolation region configured such that the device region is surrounded by the isolation region;
forming a contact layer on the device region;
providing a superstrate on a top surface of the device region and the contact layer; and
disposing a micro-optical device on a top surface of the superstrate.