Abstract
Laser ablation of GaN thin film and GaN/Sapphire structure for the application o flight emitting diodes (LEDs) has been performed. Edge quality and surface roughness of the specimens are compared using scanning electron microscopy (SEM) and atomic force microscopy (AFM) after laser processing by the 3
harmonic Nd:YAG laser, KrF excimer laser and Ti-sapphire femtosecond laser. Dependence of laser ablation rate on the processing parameters, such as laser fluence, scanning speed and pulse repetition rate with the laser irradiation is also investigated. Device characteristics of the specimens after the laser microprocessing are also analyzed.