The anisotropic distribution of dislocations and tilts in metamorphic GaInAs/AlInAs buffers grown on GaAs substrates with miscut angles toward (1 1 1)A

• Metamorphic GaInAs/AlInAs buffers are anisotropic in the two <1 1 0> directions.
• Higher dislocation density type in the two <1 1 0> directions depends on miscuts.
• A modified model was proposed to quantify the value of tilts.

The metamorphic GaInAs/AlInAs buffers grown by metal organic chemical vapor deposition (MOCVD) on GaAs substrates with miscut angles toward (1 1 1)A exhibit anisotropic properties in the two 〈1 1 0〉 directions. A higher dislocation density is observed along [1 1 0] direction for samples with substrate miscuts of 2° and 7°, while along [1 −1 0] direction for samples with a substrate miscut of 15°. The different nucleation energies and glide velocities of α and β dislocations contribute to the anisotropic dislocation distribution for the 2° and 7° samples, however, the unequal resolved shear stress (RSS) distribution between different slip systems introduced by the miscut is responsible for the 15° sample. A modified model is proposed to determine the tilt angle of epilayer with respect to the substrates, and the results show that different tilt angles in the two 〈1 1 0〉 directions is mainly attributed to the different strain relaxation in two 〈1 1 0〉 directions caused by the miscut toward (1 1 1)A.