SAMCO is presenting a paper at the International Conference on Compound Semiconductor Manufacturing Technology (CS MANTECH 2012) titled "Chlorine-Based ICP Etching for Improving the Luminance Efficiency in Nitride LEDs."

Abstract:
In this research, formation of fine cone-shaped patterns called PSS (Patterned Sapphire Substrate), and reverse-taper etching of GaN sidewalls were carried out using chlorine-based ICP-RIE (Inductively Coupled Plasma -Reactive Ion Etching) in order to improve the external luminance efficiency of GaN-LED (Gallium Nitride - Light Emitting Diodes). Dry etching systems with a special ICP coil called SSTC (Symmetrically Shielded Tornado Coil) [1] are suited for the formation of PSS, and by controlling parameters such as the flow rates of Cl2, BCl3, and Ar, process pressure, ICP RF power, and bias electrode RF power, a cone profile with a curved surface can be formed without forming micro trenches. Also it was confirmed that an etching rate of 100 nm/min, and a selectivity of 1.3 over photo resist (PR) were achieved. Furthermore, reverse-taper etching of GaN was carried out with the same system, and smooth, 70° sidewalls were obtained employing a Ni mask.