Free-standing a-plane GaN substrates grown by HVPE

A-plane free-standing GaN was grown on a-plane GaN templates by HVPE. A-plane GaN templates were grown on r-plane sapphire by MOCVD with multilayer high-low-high temperature AlN buffer layers. A regrowth method was used for growing GaN through HVPE. First, GaN was grown on a-plane GaN templates, followed by separating the a-plane GaN film from r-plane sapphire using LLO. Then, the GaN films were regrown using HVPE. The resulting free-standing GaN contained some voids, which causes to release the stress.