High-Efficiency Vertical Cavity Surface Emitting Laser Fabrication

Background

Vertical cavity surface emitting lasers (VCSELs) are a promising technology for applications in virtual and augmented reality (VR/AR) hardware. However, the tensile strain between the AlN and GaN layers of these devices prevents intuitive fabrication of distributed Bragg’s reflectors (DBR) for a resonant cavity. This obstacle results in reduced device efficiency and hinders the mass manufacture of VCSELs. Lattice-matched AlInN/GaN DBRs, nano-porous DBRs, and double dielectric DBRs via various overgrowth or film transfer strategies are all solutions to this obstacle, though each carry their own disadvantages.

Description

Researchers at the University of California, Santa Barbara have addressed the efficiency barrier in VCSELs by leveraging epitaxial lateral overgrowth (ELO) and a novel approach to foreign substrate removal. This technology produces crack-free, long lifetime devices with high crystal quality and significantly reduced defect densities and stacking faults compared to devices made directly on a native substrate. This approach is applicable to devices on Si, SiC, and sapphire substrates, regardless of their crystal orientation, and uses liftoff methods that do not damage the device. If a long resonant cavity is desired, this invention can also be applied to devices with curved mirrors.

Advantages

• Produces highly efficient, crack free, long lifetime VCSELs
• Simplifies fabrication process with flexible substrate requirements and damage free liftoff techniques
• Improves crystalline quality with reduced stacking faults and dislocation density

Applications

• VSCELs
• AR/VR

Patent Status