FABRICATION OF GAN AND III-NITRIDE ALLOYS FREESTANDING EPILAYERS MEMBRANES USING A NONBONDING LASER LIFT-OFF TECHNIQUE

摘要

Using a laser lift-off (LLO) nonbonding technique, freestanding 4-layer GaN/AlGaN heterostructure membranes have been formed. A 4x4 mm mask was attached to the area at the center of the most-upper AlGaN layer was attached using a nonbonding material such as vacuum grease. A microscopic slide attached by an adhesive provided support for the structure during the laser lift-off without bonding to the layers. The vacuum grease and the mask isolated the adhesive from the structure at the center. The microscopic slide served as a temporarily nonbonding handle substrate. Laser lift-off of the sapphire substrate from the heterostructures was performed. The remaining adhesive served as a supporting frame for the structure making a free-standing 4-layer GaN/AGaN heterostructure membrane. Other frameless freestanding membranes can be fabricated for a variety of applications including further Ill-nitride growth, heterogeneous integration, packaging of micro systems, and thin film patterns.