23‐1: Invited Paper: Roll‐to‐Roll Manufacturing of GaN‐based LED Sheets for MicroLED Display Application

Abstract

iBeam Materials is developing a revolutionary new technology to fabricate large‐area inexpensive sheets of GaN‐based LEDs and devices directly on large‐area metal foils. This new technology is based on using ion‐beam crystal alignment to fabricate templates for epitaxial GaN films on flexible metal foil, that are lattice‐matched, as well as thermally highly conductive and thermally matched to GaN. The ion beam assisted deposition (IBAD) texturing process is used to prepare biaxially aligned films as templates for GaN epitaxy. Epitaxial GaN films have been grown on these engineered flexible metal substrates. We have achieved GaN films of several microns in thickness on polycrystalline metal foils that have typical threading dislocation densities of 4 – 8 x 108/cm2. We then used these epitaxial GaN films on IBAD/polycrystalline metal foil as templates to deposit epitaxial multi‐quantum well light emitting diode (LED) InGaN structures. InGaN LED devices were successfully fabricated and patterned into MicroLED arrays on metal foil. We observe photoluminescence from these LED structures with 70% of the intensity compared to LEDs fabricated on sapphire. We discuss how these LED devices could be manufactured using a roll‐to‐roll process and cost reductions that result from this. Large‐area LED sheets can then be used to monolithically integrate MicroLEDs into paper‐thin and flexible displays.