Integration of GaN thin films with dissimilar substrate materials by Pd-Inmetal bonding and laser lift-off

Gallium nitride (GaN) thin films grown on sapphire substrates were successf ully bonded and transferred onto GaAs, Si, and polymer "receptor" substrate s using a low-temperature Pd-In bond followed by a laser lift-off (LLO) pro cess to remove the sapphire growth substrate. The GaN/sapphire structures w ere joined to the receptor substrate by pressure bonding a Pd-In bilayer co ated GaN surface onto a Pd coated receptor substrate at a temperature of 20 0 degrees C. X-ray diffraction showed that the intermetallic compound PdIn3 had formed during the bonding process. LLO, using a single 600 mJ/cm(2), 3 8 ns KrF (248 nm) excimer laser pulse directed through the transparent sapp hire substrate, followed by a low-temperature heat treatment, completed the transfer of the GaN onto the "receptor" substrate. Cross-sectional scannin g electron microscopy and x-ray rocking curves showed that the film quality did not degrade significantly during the bonding and LLO process.