A New Method for Lift-off of III-Nitride Semiconductors for Heterogeneous Integration
Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 3 Research Link, Singapore, 117602, Singapore
Nanoscale Research Letters 2010, 5:1051-1056 doi:10.1007/s11671-010-9601-6Published: 22 April 2010
The release and transfer of GaN epilayers to other substrates is of interest for a variety of applications, including heterogeneous integration of silicon logic devices, III–V power devices and optical devices. We have developed a simple wet chemical etching method to release high-quality epitaxial III-nitride films from their substrates. This method builds on a nanoepitaxial lateral overgrowth (NELO) process that provides III-Nitride films with low dislocation densities. NELO is accomplished using a nanoporous mask layer patterned on GaN substrates. Chemical removal of the SiO2 layer after growth of III-Nitride overlayers causes fracture at the interface between the GaN film and the original GaN substrate, resulting in free-standing GaN films with nanostructured surfaces on one side. These layers can be transferred to other substrates, and the nano-structured surface can be used in photonic devices, or planarized for power devices.