Structural investigation of metalorganic chemical-vapor-deposition-grown InGaAs layers on misoriented GaAs substrates

InGaAs layers were grown by metalorganic chemical vapor deposition (MOCVD) using linearly graded buffer layers on exactly oriented and misoriented GaA s(001) substrates toward [100]. The material quality was determined by opti cal microscopy, X-ray diffraction, atomic force microscopy and transmission electron microscopy investigation: A smooth surface was difficult to obtai n on exactly oriented substrates. Layers on misoriented substrates showed s moother surface morphology and reduced linewidth of X-ray rocking curves th an those on exactly oriented substrates. The radius of curvature of the sam ple for the tilted substrate was larger than that for the untilted substrat e. These findings suggest that the introduction of dislocations is enhanced and the misfit dislocation distribution in the graded buffer layers become s uniform with the use of the misoriented substrates.