Design and Fabrication of Long -Wavelength Vertical -Cavity Surface -Emitting Lasers Using Wafer Bonding Technologies
type: CreativeWork
description: Long-wavelength vertical-cavity surface-emitting lasers (VCSELs) emitting at 1.55 mum from GaInAsP/InP heterostructures are important optical sources for high-speed fiber-optic commutations. However, their development has been obstructed by the material disadvantages associated with the GaInAsP/InP distributed Bragg reflector (DBR) and the fabrication complexity of direct wafer bonding. In this work, a novel VCSEL fabrication method facilitated with new wafer bonding techniques has been developed to overcome these limitations. This process scheme provides more options on the DBR and substrate materials for long-wavelength VCSELs. In addition, the new wafer bonding techniques are less stringent on process requirements than the previous arts. Thus, the GaInAsP/InP VCSELs can be easily fabricated on lattice-mismatched substrates with high-contrast composite DBRs for a better performance, and therefore the need to grow thick epitaxial DBRs is eliminated. During the process development, substrate-independent DBRs such as polycrystalline-GaAs/Al-oxide, amorphous Si/Al-oxide, Si/Mg-oxide, and (Ga,As)/(Al,As) were investigated. New wafer bonding techniques using either spin-on glass or AuGeNiCr metal alloys as the bonding medium were developed. Using these wafer bonding techniques, the bonding interface can be formed outside the VCSEL cavity at low temperatures, reducing the mechanical and thermal impacts to the active region. In addition, processes for device formation such as ohmic contacts and chemical etching were studied and integrated. The results lead to the use of Si/Al-oxide DBRs and the metallic wafer bonding for the VCSEL fabrication. The Si/Al-oxide DBR provides a reflectance above 99.5% in six periods with a low thermal resistance and a broad stop bandwidth. The metallic wafer bonding offers a robust bonding interface, excellent thermal stability and optical reflectance. It also has a large process latitude and integration capability. Using the metallic bonding…
abstract: Long-wavelength vertical-cavity surface-emitting lasers (VCSELs) emitting at 1.55 mum from GaInAsP/InP heterostructures are important optical sources for high-speed fiber-optic commutations. However, their development has been obstructed by the material disadvantages associated with the GaInAsP/InP distributed Bragg reflector (DBR) and the fabrication complexity of direct wafer bonding. In this work, a novel VCSEL fabrication method facilitated with new wafer bonding techniques has been developed to overcome these limitations. This process scheme provides more options on the DBR and substrate materials for long-wavelength VCSELs. In addition, the new wafer bonding techniques are less stringent on process requirements than the previous arts. Thus, the GaInAsP/InP VCSELs can be easily fabricated on lattice-mismatched substrates with high-contrast composite DBRs for a better performance, and therefore the need to grow thick epitaxial DBRs is eliminated. During the process development, substrate-independent DBRs such as polycrystalline-GaAs/Al-oxide, amorphous Si/Al-oxide, Si/Mg-oxide, and (Ga,As)/(Al,As) were investigated. New wafer bonding techniques using either spin-on glass or AuGeNiCr metal alloys as the bonding medium were developed. Using these wafer bonding techniques, the bonding interface can be formed outside the VCSEL cavity at low temperatures, reducing the mechanical and thermal impacts to the active region. In addition, processes for device formation such as ohmic contacts and chemical etching were studied and integrated. The results lead to the use of Si/Al-oxide DBRs and the metallic wafer bonding for the VCSEL fabrication. The Si/Al-oxide DBR provides a reflectance above 99.5% in six periods with a low thermal resistance and a broad stop bandwidth. The metallic wafer bonding offers a robust bonding interface, excellent thermal stability and optical reflectance. It also has a large process latitude and integration capability. Using the metallic bonding…
author: Lin, Hung-Cheng
language: eng
keywords: Engineering, Electronics and Electrical
date published: 2015-09-25T20:08:08Z
date modified: 2026-07-22T22:26:14Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/80780