Development of selective lateral photoelectrochemical etching of InGaN/GaN for lift-off applications

The authors have developed a wet band gap-selective photoelectrochemical etching process to produce deep undercuts (similar to 500 mum) into InGaN/GaN heterostructures. These undercuts were used in a lift-off process which successfully transferred device-scale (100 mum diameter, 5 mum thick) disks from their underlying sapphire substrates to another substrate. Experiments were conducted using a lamp-and-filter arrangement, employing n-type and p-type GaN pieces as filters. Polishing was conducted to smooth the resulting substrate-transferred GaN disks. (C) 2001 American Institute of Physics.