부산대학교 도서관

We investigated the Al₂O₃ patterning process for GaN (Gallium Nitride)-based LED (Light Emitting Diode) fabrication using PSS (Patterned Sapphire Substrate). PSS is one of the methods to enhance the internal quantum and extraction efficiency. Reflectance of Al₂O₃ surface is calculated. Condition of Al₂O₃ surface is shaped flat, half sphere and cone. It is confirmed irradiance that patterned substrate is increased 7.84 % than flat substrate. Therefore, we needed patterned substrate for improved illumination than flat substrate. And we studied height of cone pattern that 1, 2 and 3 ㎛. Although height is not effected the whole irradiance, it is increased irradiance in substrate center. It is resulted positive effects narrowed angle of illumination. We confirmed some results that Al₂O₃ surface can be fabricated various pattern. But when 2 inch Al₂O₃ substrate is patterned for etch mask, conventional photo-lithography has many problems. So, it is fabricated etch mask using UV imprint lithography. It is made Al₂O₃, PDMS and SU-8 mold for embossing process. These results will be many useful information in LED industrial and research.