Metamorphic molecular beam epitaxy growth and selective wet etching for epitaxial layer lift-off of AlAsSb toward optical waveguides with high optical confinement

Abstract In this study, we performed epitaxial layer lift-off (ELO) of AlAs 0.37 Sb 0.63 layer toward realizing AlAs 0.37 Sb 0.63 /In 0.75 Ga 0.25 As systems on SiO 2 . This will enable high optical confinement in the AlAs 0.37 Sb 0.63 /In 0.75 Ga 0.25 As systems to be achieved owing to the large refractive index contrast ( Δ n ∼ 1.6 ) . ELO consists of two processes: the first is adhesive wafer bonding using positive photoresist and the second is two-step selective wet etching. Metamorphic molecular beam epitaxy was used to grow selective etching layers between the substrate and the AlAs 0.37 Sb 0.63 . We confirmed that the metamorphic growth did not degrade the crystal quality and ELO was successful. Therefore, ELO improves optical confinement of AlAs 0.37 Sb 0.63 and will be able to improve performance of all optical intersubband switches using the AlAs 0.37 Sb 0.63 /In 0.75 Ga 0.25 As systems.