Micro-Raman study of the residual stress in molecular-beam-epitaxy-grown Al xGa 1− xAs/GaAs multilayer structures

Abstract

Extensive Raman-scattering investigations in the cleaved cross-sections of molecular-beam-epitaxy-grown Al x Ga 1− x As/ GaAs multilayer structures on GaAs or silicon substrates have been carried out by micro-Raman spectroscopy. The structures of the epitaxial layers are Al 0.3Ga 0.7As/Al 0.2Ga 0.8As/Al 0.1Ga 0.9As/GaAs (type A) and Al 0.1Ga 0.9As/Al 0.2Ga 0.8As/Al 0.3Ga 0.7As/GaAs (type B). The largest residual stress was observed in the Al 0.3Ga 0.7As layer of the type B structure on GaAs substrate and the value was estimated to be about 1.5 × 10 10 dyn cm −2 in the compressive mode. It was also found that the mode of the residual stress in the substrates differed according to the epitaxial structures grown on them. A model of residual stress in Al x Ga 1− x As/ GaAs multilayers grown on GaAs or silicon substrates is proposed: namely, if a substrate exists on the Al 0.1Ga 0.9As side, compressive stress acts on the substrate, and on the Al 0.3Ga 0.7As side, tensile stress acts.