A fabrication of GaN micro-lens

Abstract

The group III-nitrides are very promising materials for optoelectronic devices light emitting diodes (LEDs) and laser diodes (LDs) in the UV to green wavelength region. To realize these devices, development of GaN dry etching technique is essential. While most dry etching studies have been concentrated on anisotropic, preferential etching using highly selective etch masks such as metals and/or SiO/sub 2/, we present a novel process of fabricating GaN convex micro-lenses using non-selective etching. The process was consisted of the thermal re-flowing of sacrificial photoresist (P.R) and non-selective dry etching technique. The GaN lenses could be applied to the surface of GaN-based LEDs to give directionality and improve the external quantum efficiency by reducing the amounts of total reflection which could be absorbed by defects in the crystal. Such elements also could be fabricated on the cavities of a variety of microcavity structures, such as vertical cavity surface emitting laser diodes (VCSELs), asymmetric Fabry-Perot modulators, resonant cavity LEDs, and resonant cavity photodetectors.