Focused ion beam nano patterning for fabrications of III-nitride light emitting diodes

Abstract

Photonic device structures often require nano scale lithography techniques for their device fabrication. The techniques are electron beam lithography and FIB(focused ion beam) pattering. Focused ion beam etching has been used as a nanolithography tool for the creation of these nanostructures without mask. We obtain nano scale mesa patterns on InGaN/GaN LED(light emitting diodes) wafer using focused ion beam and characterized. The InGaN/GaN LED wafer was grown by molecular organic vapor deposition (MOCVD). To reduce the surface damage during FIB patterning, we used a dielectric mask layer and wet etching to eliminate re-deposition of sputtering materials and Ga+ ion implantations and ion damage layer during FIB patterning, and finally, removed SiO₂ with wet etching. A metal thin layer was deposited by an ion beam sputter to avoid charging effects during FIB patterning. We obtain a 2-Dimensional patterning for the fabrication of the high brightness LEDs. This FIB pattering technique can be applied to nanofabrication optoelectronic devices.