Self-separated freestanding GaN grown on patterned substrate by Hydride Vapor Phase Epitaxy

A freestanding Gallium Nitride bulk is obtained without using laser lift-off technology. Two techniques such as mask-less ELOG and air-bridge structure are applied on patterned substrate. A self-separated result is successfully demonstrated by using mask-less ELOG and air-bridge structure. Due to the thermal coefficient of expansion (TCE) mismatch between the GaN layer and the non-native (foreign) substrate, separation happens during cooling down after HVPE growth. Both two structures successfully help to lift GaN off the substrate. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)