III-nitride thin film liftoff using electrochemical etching

Abstract

We report a selective electrochemical etching-based liftoff technique for III-nitride thin films using a heavily Si-doped sacrificial layer. This method enables the detachment of the millimeter-sized III-nitride thin films with tunable thickness from arbitrary substrates, achieving minimal damage and sub-nanometer liftoff surface roughness, offering more flexibility than traditional liftoff methods such as laser liftoff. Structure and optical characterization confirm the preservation of the crystal quality throughout the process. Notably, InGaN-based blue μLEDs were lifted off and transferred onto Si substrates, maintaining excellent optoelectronic properties, showing great potential in mass transfer of nitride-based μLEDs for micro-display. This proof-of-concept demonstration highlights a scalable, low-damage pathway for heterogeneous integration of III-nitride materials onto diverse platforms for advanced optoelectronic applications.