3d Gan Leds - Technologies And Analytics

3D GaN structures attract a lot of attention since they are expected to open up new routes to solid state-based high power light engines. In this paper we present different technologies employed by the Institute of Semiconductor Technology at TU Braunschweig to manufacture 3D GaN structures with a core-shell geometry or an axially embedded light emitting structure. Especially the core-shell design offers a dramatically enhanced active area per chip, since the active area is scaling with the height of the 3D structures. New metrological approaches to analyze these nanostructures are necessary, as conventional "planar" techniques cannot be applied. By combining high resolution scanning electron microscopy with electrical and optical measurements we could achieve insight into these structures. Besides the optical characterization of ensembles and single structures we also present a way to model the paths of light emitted by single microLEDs inside an ordered pattern of LED structures.