Demonstration of atmospheric plasma activated direct bonding of N-polar GaN and β-Ga2O3 (001) substrates.

Direct wafer bonding of β-Ga₂O₃ and N-polar GaN at a low temperature was achieved by acid treatment and atmospheric plasma activation. The β-Ga₂O₃/GaN surfaces were atomically bonded without any loss in crystalline quality at the interface. The impact of post-annealing temperature on the quality of bonding interfaces was investigated. Post-annealing at temperatures higher than 700 °C increases the area of voids at bonded interfaces probably due to the difference in the coefficient of thermal expansion. The integration of β-Ga₂O₃ on the GaN substrate achieved in this work is one of the promising approaches to combine the material merits of both GaN and Ga₂O₃ targeting the fabrication of novel GaN/β-Ga₂O₃ high-frequency and high-power electronics as well as optoelectronic devices. [ABSTRACT FROM AUTHOR]