Rapid delamination of GaN coatings with femtosecond laser lift-off technique

In this work we present femtosecond laser lift off (LLO) technique for GaN coating separation from sapphire substrates. We demonstrate that using rapid raster scanning technique it is possible to achieve successful delamination of GaN coatings with low surface roughness without any stitching artifacts and at industrial processing rate. Several delamination regimes can be identified in femtosecond LLO: thermal decomposition, stress induced peeling. These results show that femtosecond laser LLO could surpass nanosecond LLO by the achieved quality and overall control of delamination processes.